Bump version numbers for 1.1.6 release.

Display new contacts at the top of the contact list

Closes #1501

See merge request briar/briar!1063

.idea/codeStyles/Project.xml

@@ -39,31 +39,6 @@
     <JetCodeStyleSettings>
       <option name="CODE_STYLE_DEFAULTS" value="KOTLIN_OFFICIAL" />
     </JetCodeStyleSettings>
-    <Objective-C-extensions>
-      <file>
-        <option name="com.jetbrains.cidr.lang.util.OCDeclarationKind" value="Import" />
-        <option name="com.jetbrains.cidr.lang.util.OCDeclarationKind" value="Macro" />
-        <option name="com.jetbrains.cidr.lang.util.OCDeclarationKind" value="Typedef" />
-        <option name="com.jetbrains.cidr.lang.util.OCDeclarationKind" value="Enum" />
-        <option name="com.jetbrains.cidr.lang.util.OCDeclarationKind" value="Constant" />
-        <option name="com.jetbrains.cidr.lang.util.OCDeclarationKind" value="Global" />
-        <option name="com.jetbrains.cidr.lang.util.OCDeclarationKind" value="Struct" />
-        <option name="com.jetbrains.cidr.lang.util.OCDeclarationKind" value="FunctionPredecl" />
-        <option name="com.jetbrains.cidr.lang.util.OCDeclarationKind" value="Function" />
-      </file>
-      <class>
-        <option name="com.jetbrains.cidr.lang.util.OCDeclarationKind" value="Property" />
-        <option name="com.jetbrains.cidr.lang.util.OCDeclarationKind" value="Synthesize" />
-        <option name="com.jetbrains.cidr.lang.util.OCDeclarationKind" value="InitMethod" />
-        <option name="com.jetbrains.cidr.lang.util.OCDeclarationKind" value="StaticMethod" />
-        <option name="com.jetbrains.cidr.lang.util.OCDeclarationKind" value="InstanceMethod" />
-        <option name="com.jetbrains.cidr.lang.util.OCDeclarationKind" value="DeallocMethod" />
-      </class>
-      <extensions>
-        <pair source="cpp" header="h" fileNamingConvention="NONE" />
-        <pair source="c" header="h" fileNamingConvention="NONE" />
-      </extensions>
-    </Objective-C-extensions>
     <XML>
       <option name="XML_LEGACY_SETTINGS_IMPORTED" value="true" />
     </XML>

bramble-android/build.gradle

@@ -11,8 +11,8 @@ android {
 	defaultConfig {
 		minSdkVersion 14
 		targetSdkVersion 26
-		versionCode 10105
-		versionName "1.1.5"
+		versionCode 10106
+		versionName "1.1.6"
 		consumerProguardFiles 'proguard-rules.txt'
 
 		testInstrumentationRunner "android.support.test.runner.AndroidJUnitRunner"
@@ -30,8 +30,8 @@ configurations {
 
 dependencies {
 	implementation project(path: ':bramble-core', configuration: 'default')
-	tor 'org.briarproject:tor-android:0.3.4.8@zip'
-	tor 'org.briarproject:obfs4proxy-android:0.0.7@zip'
+	tor 'org.briarproject:tor-android:0.3.5.8@zip'
+	tor 'org.briarproject:obfs4proxy-android:0.0.9@zip'
 
 	annotationProcessor 'com.google.dagger:dagger-compiler:2.19'
 

bramble-android/src/main/java/org/briarproject/bramble/account/AndroidAccountManager.java

@@ -12,11 +12,15 @@ import org.briarproject.bramble.api.identity.IdentityManager;
 import org.briarproject.bramble.util.IoUtils;
 
 import java.io.File;
+import java.util.HashSet;
+import java.util.Set;
 import java.util.logging.Logger;
 
 import javax.annotation.Nullable;
 import javax.inject.Inject;
 
+import static android.os.Build.VERSION.SDK_INT;
+
 class AndroidAccountManager extends AccountManagerImpl
 		implements AccountManager {
 
@@ -89,20 +93,42 @@ class AndroidAccountManager extends AccountManagerImpl
 				LOG.warning("Could not clear shared preferences");
 		}
 		// Delete files, except lib and shared_prefs directories
+		Set<File> files = new HashSet<>();
 		File dataDir = new File(appContext.getApplicationInfo().dataDir);
-		File[] children = dataDir.listFiles();
-		if (children == null) {
+		@Nullable
+		File[] fileArray = dataDir.listFiles();
+		if (fileArray == null) {
 			LOG.warning("Could not list files in app data dir");
 		} else {
-			for (File child : children) {
-				String name = child.getName();
+			for (File file : fileArray) {
+				String name = file.getName();
 				if (!name.equals("lib") && !name.equals("shared_prefs")) {
-					IoUtils.deleteFileOrDir(child);
+					files.add(file);
 				}
 			}
 		}
+		files.add(appContext.getFilesDir());
+		files.add(appContext.getCacheDir());
+		addIfNotNull(files, appContext.getExternalCacheDir());
+		if (SDK_INT >= 19) {
+			for (File file : appContext.getExternalCacheDirs()) {
+				addIfNotNull(files, file);
+			}
+		}
+		if (SDK_INT >= 21) {
+			for (File file : appContext.getExternalMediaDirs()) {
+				addIfNotNull(files, file);
+			}
+		}
+		for (File file : files) {
+			IoUtils.deleteFileOrDir(file);
+		}
 		// Recreate the cache dir as some OpenGL drivers expect it to exist
-		if (!new File(dataDir, "cache").mkdir())
+		if (!new File(dataDir, "cache").mkdirs())
 			LOG.warning("Could not recreate cache dir");
 	}
+
+	private void addIfNotNull(Set<File> files, @Nullable File file) {
+		if (file != null) files.add(file);
+	}
 }

bramble-android/src/main/java/org/briarproject/bramble/battery/AndroidBatteryManager.java

@@ -19,9 +19,7 @@ import javax.inject.Inject;
 import static android.content.Intent.ACTION_BATTERY_CHANGED;
 import static android.content.Intent.ACTION_POWER_CONNECTED;
 import static android.content.Intent.ACTION_POWER_DISCONNECTED;
-import static android.os.BatteryManager.BATTERY_STATUS_CHARGING;
-import static android.os.BatteryManager.BATTERY_STATUS_FULL;
-import static android.os.BatteryManager.EXTRA_STATUS;
+import static android.os.BatteryManager.EXTRA_PLUGGED;
 import static java.util.logging.Level.INFO;
 import static java.util.logging.Logger.getLogger;
 
@@ -48,9 +46,8 @@ class AndroidBatteryManager implements BatteryManager, Service {
 		IntentFilter filter = new IntentFilter(ACTION_BATTERY_CHANGED);
 		Intent i = appContext.registerReceiver(null, filter);
 		if (i == null) return false;
-		int status = i.getIntExtra(EXTRA_STATUS, -1);
-		return status == BATTERY_STATUS_CHARGING ||
-				status == BATTERY_STATUS_FULL;
+		int status = i.getIntExtra(EXTRA_PLUGGED, 0);
+		return status != 0;
 	}
 
 	@Override

bramble-android/src/test/java/org/briarproject/bramble/account/AndroidAccountManagerTest.java

@@ -112,6 +112,8 @@ public class AndroidAccountManagerTest extends BrambleMockTestCase {
 		// Other directories should be deleted
 		File potatoDir = new File(testDir, ".potato");
 		File potatoFile = new File(potatoDir, "file");
+		File filesDir = new File(testDir, "filesDir");
+		File externalCacheDir = new File(testDir, "externalCacheDir");
 
 		context.checking(new Expectations() {{
 			oneOf(prefs).edit();
@@ -128,6 +130,12 @@ public class AndroidAccountManagerTest extends BrambleMockTestCase {
 			will(returnValue(true));
 			oneOf(app).getApplicationInfo();
 			will(returnValue(applicationInfo));
+			oneOf(app).getFilesDir();
+			will(returnValue(filesDir));
+			oneOf(app).getCacheDir();
+			will(returnValue(cacheDir));
+			oneOf(app).getExternalCacheDir();
+			will(returnValue(externalCacheDir));
 		}});
 
 		assertTrue(dbDir.mkdirs());
@@ -140,6 +148,8 @@ public class AndroidAccountManagerTest extends BrambleMockTestCase {
 		assertTrue(cacheFile.createNewFile());
 		assertTrue(potatoDir.mkdirs());
 		assertTrue(potatoFile.createNewFile());
+		assertTrue(filesDir.mkdirs());
+		assertTrue(externalCacheDir.mkdirs());
 
 		accountManager.deleteAccount();
 
@@ -153,6 +163,8 @@ public class AndroidAccountManagerTest extends BrambleMockTestCase {
 		assertFalse(cacheFile.exists());
 		assertFalse(potatoDir.exists());
 		assertFalse(potatoFile.exists());
+		assertFalse(filesDir.exists());
+		assertFalse(externalCacheDir.exists());
 	}
 
 	@After

bramble-android/witness.gradle

@@ -1,46 +1,45 @@
 dependencyVerification {
     verify = [
         'cglib:cglib:3.2.0:cglib-3.2.0.jar:adb13bab79712ad6bdf1bd59f2a3918018a8016e722e8a357065afb9e6690861',
-        'com.android.tools.analytics-library:protos:26.2.1:protos-26.2.1.jar:2f371f5b1f551e85ab08be4d6a2873471b3d44afd1ebf6aa3298f3b796bf691f',
-        'com.android.tools.analytics-library:shared:26.2.1:shared-26.2.1.jar:4c1e4e705fa4d45f23aaea230557f6508155012d9c296337787c1d7b26a97f5a',
-        'com.android.tools.analytics-library:tracker:26.2.1:tracker-26.2.1.jar:4a624ecc976539f755ddb0bb8dfc2dd3d08326cfec59a098dbd70f701ca7fb75',
-        'com.android.tools.build:aapt2:3.2.1-4818971:aapt2-3.2.1-4818971-linux.jar:f431b6f96c91a2c155144b091a9c97d9805c589fe8efc9c930b6cd346cb60a1e',
-        'com.android.tools.build:apksig:3.2.1:apksig-3.2.1.jar:2b46f2feffea66037aab29e4261b2433c190194a6ef97b958511eb157f2ccba5',
-        'com.android.tools.build:apkzlib:3.2.1:apkzlib-3.2.1.jar:c39ad0313905932431fe81c8899c2cf39a4d92ad6c4edcaa4b25432f461452aa',
-        'com.android.tools.build:builder-model:3.2.1:builder-model-3.2.1.jar:a9f68e6abcec122f9cb5ad352d3f05a3eb03acbcdca95e4d25c16310c2c965ff',
-        'com.android.tools.build:builder-test-api:3.2.1:builder-test-api-3.2.1.jar:533ac6c2b5884bb54967a33791f2628dfdfac7981af39417a333b43d4379b6be',
-        'com.android.tools.build:builder:3.2.1:builder-3.2.1.jar:aedcbfd115dbe91d09b4113e66ef50589b558d0aa3b2f133b1d867c9b87fae83',
-        'com.android.tools.build:gradle-api:3.2.1:gradle-api-3.2.1.jar:57cf0ac5ac1dca8afdb3f62b94265e776e7dcfa641cc3844fb53a05193de208d',
-        'com.android.tools.build:manifest-merger:26.2.1:manifest-merger-26.2.1.jar:8830573263361035d38cfdcb51e2db94029c93865b21334f5fbf8a27984281a6',
-        'com.android.tools.ddms:ddmlib:26.2.1:ddmlib-26.2.1.jar:a4bf0a29a19980bf27269465cc782064656750b77c26728f82f9e148b705218b',
-        'com.android.tools.external.com-intellij:intellij-core:26.2.1:intellij-core-26.2.1.jar:4925ad1892c2687cb1a63427d440ef519c8c59215fefe0dc5d541d5d411fcafe',
-        'com.android.tools.external.com-intellij:kotlin-compiler:26.2.1:kotlin-compiler-26.2.1.jar:daa064fd708f340ee25fb9823c4c74104ac77f1370b76d907eb9ae6daec0a2ae',
-        'com.android.tools.external.org-jetbrains:uast:26.2.1:uast-26.2.1.jar:f10f7258d2ab9189562cc0f9ad838c0378fdba439229173390a99de02ebac75b',
-        'com.android.tools.layoutlib:layoutlib-api:26.2.1:layoutlib-api-26.2.1.jar:ddbf4fca123733fa011595b1cc1f4ac2937ed327b60990711fafc33c775c2ade',
-        'com.android.tools.lint:lint-api:26.2.1:lint-api-26.2.1.jar:3b57e739de567b98bc9ab56c2c0ee66fc026b4adf5843e8f9804ca0666a6f66e',
-        'com.android.tools.lint:lint-checks:26.2.1:lint-checks-26.2.1.jar:c86f4cc9aaee722ee4ad70062f7b5af91e9b041914af27adc09f545ab0fb3bc6',
-        'com.android.tools.lint:lint-gradle-api:26.2.1:lint-gradle-api-26.2.1.jar:2283e7af32e301565f2a797e531f0fc8c648077d457afb3ffdddbee638976c2f',
-        'com.android.tools.lint:lint-gradle:26.2.1:lint-gradle-26.2.1.jar:8fd90b2f3ec788cbb9801c07ab3e1ea2255aa31a6093157d7ea0ff13d0315ecb',
-        'com.android.tools.lint:lint-kotlin:26.2.1:lint-kotlin-26.2.1.jar:7a6a5d2b18f69cf1b900d857c2632b4c683713c533295933b8b759f8cab4a877',
-        'com.android.tools.lint:lint:26.2.1:lint-26.2.1.jar:7848b82ae988b90dee259ae7c7e86e05cbf52db6cd21c8bbd38ce7df08f3f8c5',
-        'com.android.tools:annotations:26.2.1:annotations-26.2.1.jar:7391c6a1e080174b96e64ceb078dadd31ce4d8a2d2fee0ec65be202126f90f24',
-        'com.android.tools:common:26.2.1:common-26.2.1.jar:a50aab2d6411ff68f4004a87c7e93d87d8e980a0ec3b352246549897ea2d78e5',
-        'com.android.tools:dvlib:26.2.1:dvlib-26.2.1.jar:72a83bf2839b1df9b1fbf67ba45d1bfb9f966cd774da4320c762b2be8f1688aa',
-        'com.android.tools:repository:26.2.1:repository-26.2.1.jar:fa74dae09103faef703df38550ad8fa244c5b6d1bf90d6198be932292b3d9cc1',
-        'com.android.tools:sdk-common:26.2.1:sdk-common-26.2.1.jar:759d4b292ca69a35cf961fca377b54158fc6c88108978006999442e80a011cf4',
-        'com.android.tools:sdklib:26.2.1:sdklib-26.2.1.jar:248df7ad5eac4aeb6f96c394c76760de4b7b89ac056e54d0c21a739368b91b45',
+        'com.android.tools.analytics-library:protos:26.3.2:protos-26.3.2.jar:50238fb4298b297217b184b9cd93c14f83536fcee829eb0ca850bdb5b53251f0',
+        'com.android.tools.analytics-library:shared:26.3.2:shared-26.3.2.jar:ddd80dcf21905018b7c0583ba72b7282f446084d4952422609a09fbf8237ef71',
+        'com.android.tools.analytics-library:tracker:26.3.2:tracker-26.3.2.jar:28c575d2d1af003e96d7b375a668ee10b2673a2dd0f6438750aa8c3b42e7d0ad',
+        'com.android.tools.build:aapt2:3.3.2-5309881:aapt2-3.3.2-5309881-linux.jar:9beead7e8b1057359049f450538aadcd3eb2a5bc3fbdd5e3296cb8fdc2a22412',
+        'com.android.tools.build:apksig:3.3.2:apksig-3.3.2.jar:84c4aaa20127c6c1fe6bdd334b3f5df71f54ad080be9029c8a10f43b6a908acd',
+        'com.android.tools.build:apkzlib:3.3.2:apkzlib-3.3.2.jar:d34e523278e5dff565eba3ef3c089d515b2b5cc7b47dc77e2f3465e5e47176ac',
+        'com.android.tools.build:builder-model:3.3.2:builder-model-3.3.2.jar:055e3db0ecee9e06b9f024034999a29cd92cb1885207b37542126bd8bcc57f46',
+        'com.android.tools.build:builder-test-api:3.3.2:builder-test-api-3.3.2.jar:0b2e4cd7615bbcad14a3c91fe45ae26693508d06e40ba06c5968b8bc24416618',
+        'com.android.tools.build:builder:3.3.2:builder-3.3.2.jar:65649704da7aef0487235fd326f0f2e99ed5cf958e80f204496e6e08a42bd9f5',
+        'com.android.tools.build:gradle-api:3.3.2:gradle-api-3.3.2.jar:3cbd47e41bb70330dd72ec2c9fe51e6173554b484a03829b5a2de9e00841e040',
+        'com.android.tools.build:manifest-merger:26.3.2:manifest-merger-26.3.2.jar:05c4a6d8b02fb9f08744876477d0a68547c03a8a9069b1f086684fa04af97c33',
+        'com.android.tools.ddms:ddmlib:26.3.2:ddmlib-26.3.2.jar:d248da8a563d6e46d2c7ebbf371a4877e00510f4ca763c0bb272d5a281bf8b85',
+        'com.android.tools.external.com-intellij:intellij-core:26.3.2:intellij-core-26.3.2.jar:6c5ecc968230e9f4dcd0fef28885379feace1f0cd8130de6f61d649c86139bf3',
+        'com.android.tools.external.com-intellij:kotlin-compiler:26.3.2:kotlin-compiler-26.3.2.jar:1007d9b07ccb49cd8eaf30fda10ed4681d4714f2f9ab2ecda39b4e539cc51bbe',
+        'com.android.tools.external.org-jetbrains:uast:26.3.2:uast-26.3.2.jar:5d1833e562ea4f38a89708dfde695f0a162cbd39d003d3dde818c3fdc2b05317',
+        'com.android.tools.layoutlib:layoutlib-api:26.3.2:layoutlib-api-26.3.2.jar:d7e61e874ab95f5c350dd38b6a95b5c9dbe0083a02001884264cdb390cb255b8',
+        'com.android.tools.lint:lint-api:26.3.2:lint-api-26.3.2.jar:5867dfd7fb4a4e161a816a5d29d045f9b542d34594c00a1efec46fb4cd0e1033',
+        'com.android.tools.lint:lint-checks:26.3.2:lint-checks-26.3.2.jar:4b163b9c93790d2771e92ba8de58a0d9e0671ffcf2ccef3cf496efd442e27517',
+        'com.android.tools.lint:lint-gradle-api:26.3.2:lint-gradle-api-26.3.2.jar:54cb282e0c054f9bed3f51302ce08b003c8ab7961dfd5a4f6de26c23cc23062f',
+        'com.android.tools.lint:lint-gradle:26.3.2:lint-gradle-26.3.2.jar:bb139615f4ce97d42cc394b9389b49b76a6eb85be6785a5d272991543b519013',
+        'com.android.tools.lint:lint:26.3.2:lint-26.3.2.jar:ef7b369f8a56a92ccb0f4c1c357666b9339e4a711a9d84747d446441746cfe4e',
+        'com.android.tools:annotations:26.3.2:annotations-26.3.2.jar:5bcce8e98b6a2f5ccf13ebcefd8f734e0b35f8b19e456575665631442ce1f7a1',
+        'com.android.tools:common:26.3.2:common-26.3.2.jar:d9f8e7f0669e9a701568e3db6a87c89cf12d8fa6811c9991e969f950215ecfac',
+        'com.android.tools:dvlib:26.3.2:dvlib-26.3.2.jar:d84aad56161c7773579303d69714ded6897c64c6ddfd7d456e453231e4dfe811',
+        'com.android.tools:repository:26.3.2:repository-26.3.2.jar:da611eeb06e9ab8750d25b9e2901e10db8e5ec6304eb4c8b7103d39e0921ea40',
+        'com.android.tools:sdk-common:26.3.2:sdk-common-26.3.2.jar:82823a3bf25e64fac33a286490f0cf5ac50c2cdb3c540149b030896bb44bf96c',
+        'com.android.tools:sdklib:26.3.2:sdklib-26.3.2.jar:424d15492af67321900963238646d27495ab60de2a5b19e6a416963bc5d6932b',
         'com.google.code.findbugs:jsr305:1.3.9:jsr305-1.3.9.jar:905721a0eea90a81534abb7ee6ef4ea2e5e645fa1def0a5cd88402df1b46c9ed',
+        'com.google.code.findbugs:jsr305:3.0.2:jsr305-3.0.2.jar:766ad2a0783f2687962c8ad74ceecc38a28b9f72a2d085ee438b7813e928d0c7',
         'com.google.code.gson:gson:2.8.0:gson-2.8.0.jar:c6221763bd79c4f1c3dc7f750b5f29a0bb38b367b81314c4f71896e340c40825',
         'com.google.dagger:dagger-compiler:2.19:dagger-compiler-2.19.jar:27a4b202a2de908182edb261f8c0a264e08e5e4733d7514bc7fbf0d31da5c0fc',
         'com.google.dagger:dagger-producers:2.19:dagger-producers-2.19.jar:a17663abe0fc38b676026950907d4c5f5e2bf338375415861eaff6e3bdb0b768',
         'com.google.dagger:dagger-spi:2.19:dagger-spi-2.19.jar:e7a6379d82c841f6aac2866948ad1eed716528707814602842a8d844ce04e2e1',
         'com.google.dagger:dagger:2.19:dagger-2.19.jar:514b6f1e0727c6572e1d65cb27e4ae668b7aeaeb93a29515182965265b609939',
-        'com.google.errorprone:error_prone_annotations:2.0.18:error_prone_annotations-2.0.18.jar:cb4cfad870bf563a07199f3ebea5763f0dec440fcda0b318640b1feaa788656b',
         'com.google.errorprone:error_prone_annotations:2.1.3:error_prone_annotations-2.1.3.jar:03d0329547c13da9e17c634d1049ea2ead093925e290567e1a364fd6b1fc7ff8',
         'com.google.errorprone:javac-shaded:9-dev-r4023-3:javac-shaded-9-dev-r4023-3.jar:65bfccf60986c47fbc17c9ebab0be626afc41741e0a6ec7109e0768817a36f30',
         'com.google.googlejavaformat:google-java-format:1.5:google-java-format-1.5.jar:aa19ad7850fb85178aa22f2fddb163b84d6ce4d0035872f30d4408195ca1144e',
-        'com.google.guava:guava:23.0:guava-23.0.jar:7baa80df284117e5b945b19b98d367a85ea7b7801bd358ff657946c3bd1b6596',
         'com.google.guava:guava:25.0-jre:guava-25.0-jre.jar:3fd4341776428c7e0e5c18a7c10de129475b69ab9d30aeafbb5c277bb6074fa9',
+        'com.google.guava:guava:26.0-jre:guava-26.0-jre.jar:a0e9cabad665bc20bcd2b01f108e5fc03f756e13aea80abaadb9f407033bea2c',
         'com.google.j2objc:j2objc-annotations:1.1:j2objc-annotations-1.1.jar:40ceb7157feb263949e0f503fe5f71689333a621021aa20ce0d0acee3badaa0f',
         'com.google.jimfs:jimfs:1.1:jimfs-1.1.jar:c4828e28d7c0a930af9387510b3bada7daa5c04d7c25a75c7b8b081f1c257ddd',
         'com.google.protobuf:protobuf-java:3.4.0:protobuf-java-3.4.0.jar:dce7e66b32456a1b1198da0caff3a8acb71548658391e798c79369241e6490a4',
@@ -68,21 +67,22 @@ dependencyVerification {
         'org.beanshell:bsh:1.3.0:bsh-1.3.0.jar:9b04edc75d19db54f1b4e8b5355e9364384c6cf71eb0a1b9724c159d779879f8',
         'org.bouncycastle:bcpkix-jdk15on:1.56:bcpkix-jdk15on-1.56.jar:7043dee4e9e7175e93e0b36f45b1ec1ecb893c5f755667e8b916eb8dd201c6ca',
         'org.bouncycastle:bcprov-jdk15on:1.56:bcprov-jdk15on-1.56.jar:963e1ee14f808ffb99897d848ddcdb28fa91ddda867eb18d303e82728f878349',
-        'org.briarproject:obfs4proxy-android:0.0.7:obfs4proxy-android-0.0.7.zip:abdfb5d889d848de9bf214f9276abbf454808a505b870819eccc9a9e985bf617',
-        'org.briarproject:tor-android:0.3.4.8:tor-android-0.3.4.8.zip:989a0352d9d8d8172cd6c2137654e165e5d2beb10ed1211bab3814e224ad1926',
+        'org.briarproject:obfs4proxy-android:0.0.9:obfs4proxy-android-0.0.9.zip:9b7e9181535ea8d8bbe8ae6338e08cf4c5fc1e357a779393e0ce49586d459ae0',
+        'org.briarproject:tor-android:0.3.5.8:tor-android-0.3.5.8.zip:42a13a6f185be1a62f42e3f30ce66a3c099ac5ec890a65e7593111b65b44a54a',
         'org.checkerframework:checker-compat-qual:2.5.3:checker-compat-qual-2.5.3.jar:d76b9afea61c7c082908023f0cbc1427fab9abd2df915c8b8a3e7a509bccbc6d',
-        'org.codehaus.groovy:groovy-all:2.4.12:groovy-all-2.4.12.jar:6a56af4bd48903d56bec62821876cadefafd007360cc6bd0d8f7aa8d72b38be4',
+        'org.checkerframework:checker-qual:2.5.2:checker-qual-2.5.2.jar:64b02691c8b9d4e7700f8ee2e742dce7ea2c6e81e662b7522c9ee3bf568c040a',
+        'org.codehaus.groovy:groovy-all:2.4.15:groovy-all-2.4.15.jar:51d6c4e71782e85674239189499854359d380fb75e1a703756e3aaa5b98a5af0',
         'org.codehaus.mojo:animal-sniffer-annotations:1.14:animal-sniffer-annotations-1.14.jar:2068320bd6bad744c3673ab048f67e30bef8f518996fa380033556600669905d',
         'org.glassfish.jaxb:jaxb-core:2.2.11:jaxb-core-2.2.11.jar:37bcaee8ebb04362c8352a5bf6221b86967ecdab5164c696b10b9a2bb587b2aa',
         'org.glassfish.jaxb:jaxb-runtime:2.2.11:jaxb-runtime-2.2.11.jar:a874f2351cfba8e2946be3002d10c18a6da8f21b52ba2acf52f2b85d5520ed70',
         'org.glassfish.jaxb:txw2:2.2.11:txw2-2.2.11.jar:272a3ccad45a4511351920cd2a8633c53cab8d5220c7a92954da5526bb5eafea',
         'org.hamcrest:hamcrest-core:1.3:hamcrest-core-1.3.jar:66fdef91e9739348df7a096aa384a5685f4e875584cce89386a7a47251c4d8e9',
         'org.hamcrest:hamcrest-library:1.3:hamcrest-library-1.3.jar:711d64522f9ec410983bd310934296da134be4254a125080a0416ec178dfad1c',
-        'org.jetbrains.kotlin:kotlin-reflect:1.2.0:kotlin-reflect-1.2.0.jar:4f48a872bad6e4d9c053f4ad610d11e4012ad7e58dc19a03dd5eb811f36069dd',
-        'org.jetbrains.kotlin:kotlin-stdlib-common:1.2.71:kotlin-stdlib-common-1.2.71.jar:63999687ff2fce8a592dd180ffbbf8f1d21c26b4044c55cdc74ff3cf3b3cf328',
-        'org.jetbrains.kotlin:kotlin-stdlib-jdk7:1.2.71:kotlin-stdlib-jdk7-1.2.71.jar:b136bd61b240e07d4d92ce00d3bd1dbf584400a7bf5f220c2f3cd22446858082',
-        'org.jetbrains.kotlin:kotlin-stdlib-jdk8:1.2.71:kotlin-stdlib-jdk8-1.2.71.jar:ac3c8abf47790b64b4f7e2509a53f0c145e061ac1612a597520535d199946ea9',
-        'org.jetbrains.kotlin:kotlin-stdlib:1.2.71:kotlin-stdlib-1.2.71.jar:4c895c270b87f5fec2a2796e1d89c15407ee821de961527c28588bb46afbc68b',
+        'org.jetbrains.kotlin:kotlin-reflect:1.3.21:kotlin-reflect-1.3.21.jar:a3065c822633191e0a3e3ee12a29bec234fc4b2864a6bb87ef48cce3e9e0c26a',
+        'org.jetbrains.kotlin:kotlin-stdlib-common:1.3.21:kotlin-stdlib-common-1.3.21.jar:cea61f7b611895e64f58569a9757fc0ab0d582f107211e1930e0ce2a0add52a7',
+        'org.jetbrains.kotlin:kotlin-stdlib-jdk7:1.3.21:kotlin-stdlib-jdk7-1.3.21.jar:a87875604fd42140da6938ae4d35ee61081f4482536efc6d2615b8b626a198af',
+        'org.jetbrains.kotlin:kotlin-stdlib-jdk8:1.3.21:kotlin-stdlib-jdk8-1.3.21.jar:5823ed66ac122a1c55442ebca5a209a843ccd87f562edc31a787f3d2e47f74d4',
+        'org.jetbrains.kotlin:kotlin-stdlib:1.3.21:kotlin-stdlib-1.3.21.jar:38ba2370d9f06f50433e06b2ca775b94473c2e2785f410926079ab793c72b034',
         'org.jetbrains.trove4j:trove4j:20160824:trove4j-20160824.jar:1917871c8deb468307a584680c87a44572f5a8b0b98c6d397fc0f5f86596dbe7',
         'org.jetbrains:annotations:13.0:annotations-13.0.jar:ace2a10dc8e2d5fd34925ecac03e4988b2c0f851650c94b8cef49ba1bd111478',
         'org.jmock:jmock-junit4:2.8.2:jmock-junit4-2.8.2.jar:f7ee4df4f7bd7b7f1cafad3b99eb74d579f109d5992ff625347352edb55e674c',

bramble-api/src/main/java/org/briarproject/bramble/api/contact/ContactExchangeListener.java

@@ -1,20 +0,0 @@
-package org.briarproject.bramble.api.contact;
-
-import org.briarproject.bramble.api.identity.Author;
-import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
-
-@NotNullByDefault
-public interface ContactExchangeListener {
-
-	void contactExchangeSucceeded(Author remoteAuthor);
-
-	/**
-	 * The exchange failed because the contact already exists.
-	 */
-	void duplicateContact(Author remoteAuthor);
-
-	/**
-	 * A general failure.
-	 */
-	void contactExchangeFailed();
-}

bramble-api/src/main/java/org/briarproject/bramble/api/contact/ContactExchangeTask.java

@@ -41,8 +41,7 @@ public interface ContactExchangeTask {
 	/**
 	 * Exchanges contact information with a remote peer.
 	 */
-	void startExchange(ContactExchangeListener listener,
-			LocalAuthor localAuthor, SecretKey masterSecret,
+	void startExchange(LocalAuthor localAuthor, SecretKey masterSecret,
 			DuplexTransportConnection conn, TransportId transportId,
 			boolean alice);
 }

bramble-api/src/main/java/org/briarproject/bramble/api/contact/ContactManager.java

@@ -13,6 +13,8 @@ import java.util.Collection;
 
 import javax.annotation.Nullable;
 
+import static org.briarproject.bramble.api.contact.PendingContact.PendingContactState.FAILED;
+
 @NotNullByDefault
 public interface ContactManager {
 
@@ -52,6 +54,35 @@ public interface ContactManager {
 			long timestamp, boolean alice, boolean verified, boolean active)
 			throws DbException;
 
+	/**
+	 * Returns the static link that needs to be sent to the contact to be added.
+	 */
+	String getRemoteContactLink();
+
+	/**
+	 * Returns true if the given link is syntactically valid.
+	 */
+	boolean isValidRemoteContactLink(String link);
+
+	/**
+	 * Requests a new contact to be added via the given {@code link}.
+	 *
+	 * @param link The link received from the contact we want to add.
+	 * @param alias The alias the user has given this contact.
+	 * @return A PendingContact representing the contact to be added.
+	 */
+	PendingContact addRemoteContactRequest(String link, String alias);
+
+	/**
+	 * Returns a list of {@link PendingContact}s.
+	 */
+	Collection<PendingContact> getPendingContacts();
+
+	/**
+	 * Removes a {@link PendingContact} that is in state {@link FAILED}.
+	 */
+	void removePendingContact(PendingContact pendingContact);
+
 	/**
 	 * Returns the contact with the given ID.
 	 */

bramble-api/src/main/java/org/briarproject/bramble/api/contact/PendingContact.java

@@ -0,0 +1,54 @@
+package org.briarproject.bramble.api.contact;
+
+import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
+
+import javax.annotation.concurrent.Immutable;
+
+@Immutable
+@NotNullByDefault
+public class PendingContact {
+
+	public enum PendingContactState {
+		WAITING_FOR_CONNECTION,
+		CONNECTED,
+		ADDING_CONTACT,
+		FAILED
+	}
+
+	private final PendingContactId id;
+	private final String alias;
+	private final PendingContactState state;
+	private final long timestamp;
+
+	public PendingContact(PendingContactId id, String alias,
+			PendingContactState state, long timestamp) {
+		this.id = id;
+		this.alias = alias;
+		this.state = state;
+		this.timestamp = timestamp;
+	}
+
+	public String getAlias() {
+		return alias;
+	}
+
+	public PendingContactState getState() {
+		return state;
+	}
+
+	public long getTimestamp() {
+		return timestamp;
+	}
+
+	@Override
+	public int hashCode() {
+		return id.hashCode();
+	}
+
+	@Override
+	public boolean equals(Object o) {
+		return o instanceof PendingContact &&
+				id.equals(((PendingContact) o).id);
+	}
+
+}

bramble-api/src/main/java/org/briarproject/bramble/api/contact/PendingContactId.java

@@ -0,0 +1,11 @@
+package org.briarproject.bramble.api.contact;
+
+import org.briarproject.bramble.api.UniqueId;
+
+public class PendingContactId extends UniqueId {
+
+	public PendingContactId(byte[] id) {
+		super(id);
+	}
+
+}

bramble-api/src/main/java/org/briarproject/bramble/api/contact/event/ContactExchangeFailedEvent.java

@@ -0,0 +1,32 @@
+package org.briarproject.bramble.api.contact.event;
+
+import org.briarproject.bramble.api.event.Event;
+import org.briarproject.bramble.api.identity.Author;
+import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
+
+import javax.annotation.Nullable;
+
+@NotNullByDefault
+public class ContactExchangeFailedEvent extends Event {
+
+	@Nullable
+	private final Author duplicateRemoteAuthor;
+
+	public ContactExchangeFailedEvent(@Nullable Author duplicateRemoteAuthor) {
+		this.duplicateRemoteAuthor = duplicateRemoteAuthor;
+	}
+
+	public ContactExchangeFailedEvent() {
+		this(null);
+	}
+
+	@Nullable
+	public Author getDuplicateRemoteAuthor() {
+		return duplicateRemoteAuthor;
+	}
+
+	public boolean wasDuplicateContact() {
+		return duplicateRemoteAuthor != null;
+	}
+
+}

bramble-api/src/main/java/org/briarproject/bramble/api/contact/event/ContactExchangeSucceededEvent.java

@@ -0,0 +1,20 @@
+package org.briarproject.bramble.api.contact.event;
+
+import org.briarproject.bramble.api.event.Event;
+import org.briarproject.bramble.api.identity.Author;
+import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
+
+@NotNullByDefault
+public class ContactExchangeSucceededEvent extends Event {
+
+	private final Author remoteAuthor;
+
+	public ContactExchangeSucceededEvent(Author remoteAuthor) {
+		this.remoteAuthor = remoteAuthor;
+	}
+
+	public Author getRemoteAuthor() {
+		return remoteAuthor;
+	}
+
+}

bramble-api/src/main/java/org/briarproject/bramble/api/contact/event/PendingContactStateChangedEvent.java

@@ -0,0 +1,34 @@
+package org.briarproject.bramble.api.contact.event;
+
+import org.briarproject.bramble.api.contact.PendingContact.PendingContactState;
+import org.briarproject.bramble.api.contact.PendingContactId;
+import org.briarproject.bramble.api.event.Event;
+import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
+
+import javax.annotation.concurrent.Immutable;
+
+/**
+ * An event that is broadcast when a pending contact's state is changed.
+ */
+@Immutable
+@NotNullByDefault
+public class PendingContactStateChangedEvent extends Event {
+
+	private final PendingContactId id;
+	private final PendingContactState state;
+
+	public PendingContactStateChangedEvent(PendingContactId id,
+			PendingContactState state) {
+		this.id = id;
+		this.state = state;
+	}
+
+	public PendingContactId getId() {
+		return id;
+	}
+
+	public PendingContactState getPendingContactState() {
+		return state;
+	}
+
+}

bramble-api/src/main/java/org/briarproject/bramble/api/plugin/TorConstants.java

@@ -16,6 +16,7 @@ public interface TorConstants {
 	String PREF_TOR_NETWORK = "network2";
 	String PREF_TOR_PORT = "port";
 	String PREF_TOR_MOBILE = "useMobileData";
+	String PREF_TOR_ONLY_WHEN_CHARGING = "onlyWhenCharging";
 
 	int PREF_TOR_NETWORK_AUTOMATIC = 0;
 	int PREF_TOR_NETWORK_WITHOUT_BRIDGES = 1;

bramble-api/src/main/java/org/briarproject/bramble/api/versioning/ClientVersioningManager.java

@@ -38,6 +38,13 @@ public interface ClientVersioningManager {
 	Visibility getClientVisibility(Transaction txn, ContactId contactId,
 			ClientId clientId, int majorVersion) throws DbException;
 
+	/**
+	 * Returns the minor version of the given client that is supported by the
+	 * given contact, or -1 if the contact does not support the client.
+	 */
+	int getClientMinorVersion(Transaction txn, ContactId contactId,
+			ClientId clientId, int majorVersion) throws DbException;
+
 	interface ClientVersioningHook {
 
 		void onClientVisibilityChanging(Transaction txn, Contact c,

bramble-api/src/main/java/org/briarproject/bramble/util/ByteUtils.java

@@ -1,7 +1,5 @@
 package org.briarproject.bramble.util;
 
-import org.briarproject.bramble.api.FormatException;
-
 public class ByteUtils {
 
 	/**
@@ -14,26 +12,15 @@ public class ByteUtils {
 	 */
 	public static final long MAX_32_BIT_UNSIGNED = 4294967295L; // 2^32 - 1
 
-	/**
-	 * The number of bytes needed to encode a 16-bit integer.
-	 */
+	/** The number of bytes needed to encode a 16-bit integer. */
 	public static final int INT_16_BYTES = 2;
 
-	/**
-	 * The number of bytes needed to encode a 32-bit integer.
-	 */
+	/** The number of bytes needed to encode a 32-bit integer. */
 	public static final int INT_32_BYTES = 4;
 
-	/**
-	 * The number of bytes needed to encode a 64-bit integer.
-	 */
+	/** The number of bytes needed to encode a 64-bit integer. */
 	public static final int INT_64_BYTES = 8;
 
-	/**
-	 * The maximum number of bytes needed to encode a variable-length integer.
-	 */
-	public static final int MAX_VARINT_BYTES = 9;
-
 	public static void writeUint16(int src, byte[] dest, int offset) {
 		if (src < 0) throw new IllegalArgumentException();
 		if (src > MAX_16_BIT_UNSIGNED) throw new IllegalArgumentException();
@@ -68,42 +55,6 @@ public class ByteUtils {
 		dest[offset + 7] = (byte) (src & 0xFF);
 	}
 
-	/**
-	 * Returns the number of bytes needed to represent 'src' as a
-	 * variable-length integer.
-	 * <p>
-	 * 'src' must not be negative.
-	 */
-	public static int getVarIntBytes(long src) {
-		if (src < 0) throw new IllegalArgumentException();
-		int len = 1;
-		while ((src >>= 7) > 0) len++;
-		return len;
-	}
-
-	/**
-	 * Writes 'src' to 'dest' as a variable-length integer, starting at
-	 * 'offset', and returns the number of bytes written.
-	 * <p>
-	 * `src` must not be negative.
-	 */
-	public static int writeVarInt(long src, byte[] dest, int offset) {
-		if (src < 0) throw new IllegalArgumentException();
-		int len = getVarIntBytes(src);
-		if (dest.length < offset + len) throw new IllegalArgumentException();
-		// Work backwards from the end
-		int end = offset + len - 1;
-		for (int i = end; i >= offset; i--) {
-			// Encode 7 bits
-			dest[i] = (byte) (src & 0x7F);
-			// Raise the continuation flag, except for the last byte
-			if (i < end) dest[i] |= (byte) 0x80;
-			// Shift out the bits that were encoded
-			src >>= 7;
-		}
-		return len;
-	}
-
 	public static int readUint16(byte[] src, int offset) {
 		if (src.length < offset + INT_16_BYTES)
 			throw new IllegalArgumentException();
@@ -132,46 +83,14 @@ public class ByteUtils {
 				| (src[offset + 7] & 0xFFL);
 	}
 
-	/**
-	 * Returns the length in bytes of a variable-length integer encoded in
-	 * 'src' starting at 'offset'.
-	 *
-	 * @throws FormatException if there is not a valid variable-length integer
-	 * at the specified position.
-	 */
-	public static int getVarIntBytes(byte[] src, int offset)
-			throws FormatException {
-		if (src.length < offset) throw new IllegalArgumentException();
-		for (int i = 0; i < MAX_VARINT_BYTES && offset + i < src.length; i++) {
-			// If the continuation flag is lowered, this is the last byte
-			if ((src[offset + i] & 0x80) == 0) return i + 1;
+	public static int readUint(byte[] src, int bits) {
+		if (src.length << 3 < bits) throw new IllegalArgumentException();
+		int dest = 0;
+		for (int i = 0; i < bits; i++) {
+			if ((src[i >> 3] & 128 >> (i & 7)) != 0) dest |= 1 << bits - i - 1;
 		}
-		// We've read 9 bytes or reached the end of the input without finding
-		// the last byte
-		throw new FormatException();
-	}
-
-	/**
-	 * Reads a variable-length integer from 'src' starting at 'offset' and
-	 * returns it.
-	 *
-	 * @throws FormatException if there is not a valid variable-length integer
-	 * at the specified position.
-	 */
-	public static long readVarInt(byte[] src, int offset)
-			throws FormatException {
-		if (src.length < offset) throw new IllegalArgumentException();
-		long dest = 0;
-		for (int i = 0; i < MAX_VARINT_BYTES && offset + i < src.length; i++) {
-			// Decode 7 bits
-			dest |= src[offset + i] & 0x7F;
-			// If the continuation flag is lowered, this is the last byte
-			if ((src[offset + i] & 0x80) == 0) return dest;
-			// Make room for the next 7 bits
-			dest <<= 7;
-		}
-		// We've read 9 bytes or reached the end of the input without finding
-		// the last byte
-		throw new FormatException();
+		if (dest < 0) throw new AssertionError();
+		if (dest >= 1 << bits) throw new AssertionError();
+		return dest;
 	}
 }

bramble-core/src/main/java/org/briarproject/bramble/contact/ContactExchangeTaskImpl.java

@@ -2,10 +2,11 @@ package org.briarproject.bramble.contact;
 
 import org.briarproject.bramble.api.FormatException;
 import org.briarproject.bramble.api.client.ClientHelper;
-import org.briarproject.bramble.api.contact.ContactExchangeListener;
 import org.briarproject.bramble.api.contact.ContactExchangeTask;
 import org.briarproject.bramble.api.contact.ContactId;
 import org.briarproject.bramble.api.contact.ContactManager;
+import org.briarproject.bramble.api.contact.event.ContactExchangeFailedEvent;
+import org.briarproject.bramble.api.contact.event.ContactExchangeSucceededEvent;
 import org.briarproject.bramble.api.crypto.CryptoComponent;
 import org.briarproject.bramble.api.crypto.SecretKey;
 import org.briarproject.bramble.api.data.BdfDictionary;
@@ -13,6 +14,7 @@ import org.briarproject.bramble.api.data.BdfList;
 import org.briarproject.bramble.api.db.ContactExistsException;
 import org.briarproject.bramble.api.db.DatabaseComponent;
 import org.briarproject.bramble.api.db.DbException;
+import org.briarproject.bramble.api.event.EventBus;
 import org.briarproject.bramble.api.identity.Author;
 import org.briarproject.bramble.api.identity.LocalAuthor;
 import org.briarproject.bramble.api.nullsafety.MethodsNotNullByDefault;
@@ -63,6 +65,7 @@ class ContactExchangeTaskImpl extends Thread implements ContactExchangeTask {
 	private final ClientHelper clientHelper;
 	private final RecordReaderFactory recordReaderFactory;
 	private final RecordWriterFactory recordWriterFactory;
+	private final EventBus eventBus;
 	private final Clock clock;
 	private final ConnectionManager connectionManager;
 	private final ContactManager contactManager;
@@ -71,7 +74,6 @@ class ContactExchangeTaskImpl extends Thread implements ContactExchangeTask {
 	private final StreamReaderFactory streamReaderFactory;
 	private final StreamWriterFactory streamWriterFactory;
 
-	private volatile ContactExchangeListener listener;
 	private volatile LocalAuthor localAuthor;
 	private volatile DuplexTransportConnection conn;
 	private volatile TransportId transportId;
@@ -81,8 +83,9 @@ class ContactExchangeTaskImpl extends Thread implements ContactExchangeTask {
 	@Inject
 	ContactExchangeTaskImpl(DatabaseComponent db, ClientHelper clientHelper,
 			RecordReaderFactory recordReaderFactory,
-			RecordWriterFactory recordWriterFactory, Clock clock,
-			ConnectionManager connectionManager, ContactManager contactManager,
+			RecordWriterFactory recordWriterFactory, EventBus eventBus,
+			Clock clock, ConnectionManager connectionManager,
+			ContactManager contactManager,
 			TransportPropertyManager transportPropertyManager,
 			CryptoComponent crypto, StreamReaderFactory streamReaderFactory,
 			StreamWriterFactory streamWriterFactory) {
@@ -90,6 +93,7 @@ class ContactExchangeTaskImpl extends Thread implements ContactExchangeTask {
 		this.clientHelper = clientHelper;
 		this.recordReaderFactory = recordReaderFactory;
 		this.recordWriterFactory = recordWriterFactory;
+		this.eventBus = eventBus;
 		this.clock = clock;
 		this.connectionManager = connectionManager;
 		this.contactManager = contactManager;
@@ -100,11 +104,9 @@ class ContactExchangeTaskImpl extends Thread implements ContactExchangeTask {
 	}
 
 	@Override
-	public void startExchange(ContactExchangeListener listener,
-			LocalAuthor localAuthor, SecretKey masterSecret,
+	public void startExchange(LocalAuthor localAuthor, SecretKey masterSecret,
 			DuplexTransportConnection conn, TransportId transportId,
 			boolean alice) {
-		this.listener = listener;
 		this.localAuthor = localAuthor;
 		this.conn = conn;
 		this.transportId = transportId;
@@ -123,8 +125,8 @@ class ContactExchangeTaskImpl extends Thread implements ContactExchangeTask {
 			out = conn.getWriter().getOutputStream();
 		} catch (IOException e) {
 			logException(LOG, WARNING, e);
-			listener.contactExchangeFailed();
 			tryToClose(conn);
+			eventBus.broadcast(new ContactExchangeFailedEvent());
 			return;
 		}
 
@@ -134,7 +136,7 @@ class ContactExchangeTaskImpl extends Thread implements ContactExchangeTask {
 			localProperties = transportPropertyManager.getLocalProperties();
 		} catch (DbException e) {
 			logException(LOG, WARNING, e);
-			listener.contactExchangeFailed();
+			eventBus.broadcast(new ContactExchangeFailedEvent());
 			tryToClose(conn);
 			return;
 		}
@@ -196,7 +198,7 @@ class ContactExchangeTaskImpl extends Thread implements ContactExchangeTask {
 			}
 		} catch (IOException e) {
 			logException(LOG, WARNING, e);
-			listener.contactExchangeFailed();
+			eventBus.broadcast(new ContactExchangeFailedEvent());
 			tryToClose(conn);
 			return;
 		}
@@ -204,7 +206,7 @@ class ContactExchangeTaskImpl extends Thread implements ContactExchangeTask {
 		// Verify the contact's signature
 		if (!verify(remoteInfo.author, remoteNonce, remoteInfo.signature)) {
 			LOG.warning("Invalid signature");
-			listener.contactExchangeFailed();
+			eventBus.broadcast(new ContactExchangeFailedEvent());
 			tryToClose(conn);
 			return;
 		}
@@ -221,15 +223,17 @@ class ContactExchangeTaskImpl extends Thread implements ContactExchangeTask {
 					conn);
 			// Pseudonym exchange succeeded
 			LOG.info("Pseudonym exchange succeeded");
-			listener.contactExchangeSucceeded(remoteInfo.author);
+			eventBus.broadcast(
+					new ContactExchangeSucceededEvent(remoteInfo.author));
 		} catch (ContactExistsException e) {
 			logException(LOG, WARNING, e);
 			tryToClose(conn);
-			listener.duplicateContact(remoteInfo.author);
+			eventBus.broadcast(
+					new ContactExchangeFailedEvent(remoteInfo.author));
 		} catch (DbException e) {
 			logException(LOG, WARNING, e);
 			tryToClose(conn);
-			listener.contactExchangeFailed();
+			eventBus.broadcast(new ContactExchangeFailedEvent());
 		}
 	}
 

bramble-core/src/main/java/org/briarproject/bramble/contact/ContactManagerImpl.java

@@ -3,6 +3,8 @@ package org.briarproject.bramble.contact;
 import org.briarproject.bramble.api.contact.Contact;
 import org.briarproject.bramble.api.contact.ContactId;
 import org.briarproject.bramble.api.contact.ContactManager;
+import org.briarproject.bramble.api.contact.PendingContact;
+import org.briarproject.bramble.api.contact.PendingContactId;
 import org.briarproject.bramble.api.crypto.SecretKey;
 import org.briarproject.bramble.api.db.DatabaseComponent;
 import org.briarproject.bramble.api.db.DbException;
@@ -19,12 +21,16 @@ import org.briarproject.bramble.api.transport.KeyManager;
 import java.util.ArrayList;
 import java.util.Collection;
 import java.util.List;
+import java.util.Random;
 import java.util.concurrent.CopyOnWriteArrayList;
+import java.util.regex.Pattern;
 
 import javax.annotation.Nullable;
 import javax.annotation.concurrent.ThreadSafe;
 import javax.inject.Inject;
 
+import static java.util.Collections.emptyList;
+import static org.briarproject.bramble.api.contact.PendingContact.PendingContactState.WAITING_FOR_CONNECTION;
 import static org.briarproject.bramble.api.identity.AuthorConstants.MAX_AUTHOR_NAME_LENGTH;
 import static org.briarproject.bramble.api.identity.AuthorInfo.Status.OURSELVES;
 import static org.briarproject.bramble.api.identity.AuthorInfo.Status.UNKNOWN;
@@ -36,6 +42,12 @@ import static org.briarproject.bramble.util.StringUtils.toUtf8;
 @NotNullByDefault
 class ContactManagerImpl implements ContactManager {
 
+	private static final int LINK_LENGTH = 64;
+	private static final String REMOTE_CONTACT_LINK =
+			"briar://" + getRandomBase32String(LINK_LENGTH);
+	private static final Pattern LINK_REGEX =
+			Pattern.compile("(briar://)?([a-z2-7]{" + LINK_LENGTH + "})");
+
 	private final DatabaseComponent db;
 	private final KeyManager keyManager;
 	private final IdentityManager identityManager;
@@ -84,6 +96,48 @@ class ContactManagerImpl implements ContactManager {
 						verified, active));
 	}
 
+	@Override
+	public String getRemoteContactLink() {
+		// TODO replace with real implementation
+		return REMOTE_CONTACT_LINK;
+	}
+
+	@SuppressWarnings("SameParameterValue")
+	private static String getRandomBase32String(int length) {
+		Random random = new Random();
+		char[] c = new char[length];
+		for (int i = 0; i < length; i++) {
+			int character = random.nextInt(32);
+			if (character < 26) c[i] = (char) ('a' + character);
+			else c[i] = (char) ('2' + (character - 26));
+		}
+		return new String(c);
+	}
+
+	@Override
+	public boolean isValidRemoteContactLink(String link) {
+		return LINK_REGEX.matcher(link).matches();
+	}
+
+	@Override
+	public PendingContact addRemoteContactRequest(String link, String alias) {
+		// TODO replace with real implementation
+		PendingContactId id = new PendingContactId(link.getBytes());
+		return new PendingContact(id, alias, WAITING_FOR_CONNECTION,
+				System.currentTimeMillis());
+	}
+
+	@Override
+	public Collection<PendingContact> getPendingContacts() {
+		// TODO replace with real implementation
+		return emptyList();
+	}
+
+	@Override
+	public void removePendingContact(PendingContact pendingContact) {
+		// TODO replace with real implementation
+	}
+
 	@Override
 	public Contact getContact(ContactId c) throws DbException {
 		return db.transactionWithResult(true, txn -> db.getContact(txn, c));

bramble-core/src/main/java/org/briarproject/bramble/plugin/tor/CircumventionProvider.java

@@ -17,16 +17,24 @@ public interface CircumventionProvider {
 	String[] BLOCKED = {"CN", "IR", "EG", "BY", "TR", "SY", "VE"};
 
 	/**
-	 * Countries where vanilla bridge connection are likely to work.
+	 * Countries where obfs4 bridge connection are likely to work.
 	 * Should be a subset of {@link #BLOCKED}.
 	 */
-	String[] BRIDGES = { "EG", "BY", "TR", "SY", "VE" };
+	String[] BRIDGES = { "CN", "IR", "EG", "BY", "TR", "SY", "VE" };
+
+	/**
+	 * Countries where obfs4 bridges won't work and meek is needed.
+	 * Should be a subset of {@link #BRIDGES}.
+	 */
+	String[] NEEDS_MEEK = {"CN", "IR"};
 
 	boolean isTorProbablyBlocked(String countryCode);
 
 	boolean doBridgesWork(String countryCode);
 
+	boolean needsMeek(String countryCode);
+
 	@IoExecutor
-	List<String> getBridges();
+	List<String> getBridges(boolean meek);
 
 }

bramble-core/src/main/java/org/briarproject/bramble/plugin/tor/CircumventionProviderImpl.java

@@ -22,6 +22,8 @@ class CircumventionProviderImpl implements CircumventionProvider {
 			new HashSet<>(asList(BLOCKED));
 	private static final Set<String> BRIDGES_WORK_IN_COUNTRIES =
 			new HashSet<>(asList(BRIDGES));
+	private static final Set<String> BRIDGES_NEED_MEEK =
+			new HashSet<>(asList(NEEDS_MEEK));
 
 	@Nullable
 	private volatile List<String> bridges = null;
@@ -40,9 +42,14 @@ class CircumventionProviderImpl implements CircumventionProvider {
 		return BRIDGES_WORK_IN_COUNTRIES.contains(countryCode);
 	}
 
+	@Override
+	public boolean needsMeek(String countryCode) {
+		return BRIDGES_NEED_MEEK.contains(countryCode);
+	}
+
 	@Override
 	@IoExecutor
-	public List<String> getBridges() {
+	public List<String> getBridges(boolean useMeek) {
 		List<String> bridges = this.bridges;
 		if (bridges != null) return new ArrayList<>(bridges);
 
@@ -53,6 +60,8 @@ class CircumventionProviderImpl implements CircumventionProvider {
 		bridges = new ArrayList<>();
 		while (scanner.hasNextLine()) {
 			String line = scanner.nextLine();
+			boolean isMeekBridge = line.startsWith("Bridge meek");
+			if (useMeek && !isMeekBridge || !useMeek && isMeekBridge) continue;
 			if (!line.startsWith("#")) bridges.add(line);
 		}
 		scanner.close();

bramble-core/src/main/java/org/briarproject/bramble/plugin/tor/TorPlugin.java

@@ -69,6 +69,7 @@ import static org.briarproject.bramble.api.plugin.TorConstants.PREF_TOR_NETWORK;
 import static org.briarproject.bramble.api.plugin.TorConstants.PREF_TOR_NETWORK_AUTOMATIC;
 import static org.briarproject.bramble.api.plugin.TorConstants.PREF_TOR_NETWORK_NEVER;
 import static org.briarproject.bramble.api.plugin.TorConstants.PREF_TOR_NETWORK_WITH_BRIDGES;
+import static org.briarproject.bramble.api.plugin.TorConstants.PREF_TOR_ONLY_WHEN_CHARGING;
 import static org.briarproject.bramble.api.plugin.TorConstants.PREF_TOR_PORT;
 import static org.briarproject.bramble.api.plugin.TorConstants.PROP_ONION_V2;
 import static org.briarproject.bramble.api.plugin.TorConstants.PROP_ONION_V3;
@@ -469,13 +470,19 @@ abstract class TorPlugin implements DuplexPlugin, EventHandler, EventListener {
 		if (!enable) callback.transportDisabled();
 	}
 
-	private void enableBridges(boolean enable) throws IOException {
+	private void enableBridges(boolean enable, boolean needsMeek)
+			throws IOException {
 		if (enable) {
 			Collection<String> conf = new ArrayList<>();
 			conf.add("UseBridges 1");
-			conf.add("ClientTransportPlugin obfs4 exec " +
-					obfs4File.getAbsolutePath());
-			conf.addAll(circumventionProvider.getBridges());
+			if (needsMeek) {
+				conf.add("ClientTransportPlugin meek_lite exec " +
+						obfs4File.getAbsolutePath());
+			} else {
+				conf.add("ClientTransportPlugin obfs4 exec " +
+						obfs4File.getAbsolutePath());
+			}
+			conf.addAll(circumventionProvider.getBridges(needsMeek));
 			controlConnection.setConf(conf);
 		} else {
 			controlConnection.setConf("UseBridges", "0");
@@ -648,8 +655,10 @@ abstract class TorPlugin implements DuplexPlugin, EventHandler, EventListener {
 			if (s.getNamespace().equals(ID.getString())) {
 				LOG.info("Tor settings updated");
 				settings = s.getSettings();
-				// Works around a bug introduced in Tor 0.3.4.8. Could be
-				// replaced with callback.transportDisabled() when fixed.
+				// Works around a bug introduced in Tor 0.3.4.8.
+				// https://trac.torproject.org/projects/tor/ticket/28027
+				// Could be replaced with callback.transportDisabled()
+				// when fixed.
 				disableNetwork();
 				updateConnectionStatus(networkManager.getNetworkStatus(),
 						batteryManager.isCharging());
@@ -685,6 +694,8 @@ abstract class TorPlugin implements DuplexPlugin, EventHandler, EventListener {
 			int network = settings.getInt(PREF_TOR_NETWORK,
 					PREF_TOR_NETWORK_AUTOMATIC);
 			boolean useMobile = settings.getBoolean(PREF_TOR_MOBILE, true);
+			boolean onlyWhenCharging =
+					settings.getBoolean(PREF_TOR_ONLY_WHEN_CHARGING, false);
 			boolean bridgesWork = circumventionProvider.doBridgesWork(country);
 			boolean automatic = network == PREF_TOR_NETWORK_AUTOMATIC;
 
@@ -699,21 +710,29 @@ abstract class TorPlugin implements DuplexPlugin, EventHandler, EventListener {
 				if (!online) {
 					LOG.info("Disabling network, device is offline");
 					enableNetwork(false);
+				} else if (!charging && onlyWhenCharging) {
+					LOG.info("Disabling network, device is on battery");
+					enableNetwork(false);
 				} else if (network == PREF_TOR_NETWORK_NEVER ||
 						(!useMobile && !wifi)) {
-					LOG.info("Disabling network due to setting");
+					LOG.info("Disabling network, device is using mobile data");
 					enableNetwork(false);
 				} else if (automatic && blocked && !bridgesWork) {
 					LOG.info("Disabling network, country is blocked");
 					enableNetwork(false);
 				} else if (network == PREF_TOR_NETWORK_WITH_BRIDGES ||
 						(automatic && bridgesWork)) {
-					LOG.info("Enabling network, using bridges");
-					enableBridges(true);
+					if (circumventionProvider.needsMeek(country)) {
+						LOG.info("Enabling network, using meek bridges");
+						enableBridges(true, true);
+					} else {
+						LOG.info("Enabling network, using obfs4 bridges");
+						enableBridges(true, false);
+					}
 					enableNetwork(true);
 				} else {
 					LOG.info("Enabling network, not using bridges");
-					enableBridges(false);
+					enableBridges(false, false);
 					enableNetwork(true);
 				}
 				if (online && wifi && charging) {

bramble-core/src/main/java/org/briarproject/bramble/versioning/ClientVersioningManagerImpl.java

@@ -89,14 +89,9 @@ class ClientVersioningManagerImpl implements ClientVersioningManager, Client,
 	public Visibility getClientVisibility(Transaction txn, ContactId contactId,
 			ClientId clientId, int majorVersion) throws DbException {
 		try {
-			Contact contact = db.getContact(txn, contactId);
-			Group g = getContactGroup(contact);
-			// Contact may be in the process of being added or removed, so
-			// contact group may not exist
-			if (!db.containsGroup(txn, g.getId())) return INVISIBLE;
-			LatestUpdates latest = findLatestUpdates(txn, g.getId());
+			LatestUpdates latest = findLatestUpdates(txn, contactId);
+			if (latest == null || latest.remote == null) return INVISIBLE;
 			if (latest.local == null) throw new DbException();
-			if (latest.remote == null) return INVISIBLE;
 			Update localUpdate = loadUpdate(txn, latest.local.messageId);
 			Update remoteUpdate = loadUpdate(txn, latest.remote.messageId);
 			Map<ClientMajorVersion, Visibility> visibilities =
@@ -110,6 +105,24 @@ class ClientVersioningManagerImpl implements ClientVersioningManager, Client,
 		}
 	}
 
+	@Override
+	public int getClientMinorVersion(Transaction txn, ContactId contactId,
+			ClientId clientId, int majorVersion) throws DbException {
+		try {
+			LatestUpdates latest = findLatestUpdates(txn, contactId);
+			if (latest == null || latest.remote == null) return -1;
+			Update remoteUpdate = loadUpdate(txn, latest.remote.messageId);
+			ClientMajorVersion cv =
+					new ClientMajorVersion(clientId, majorVersion);
+			for (ClientState remote : remoteUpdate.states) {
+				if (remote.majorVersion.equals(cv)) return remote.minorVersion;
+			}
+			return -1;
+		} catch (FormatException e) {
+			throw new DbException(e);
+		}
+	}
+
 	@Override
 	public void createLocalState(Transaction txn) throws DbException {
 		if (db.containsGroup(txn, localGroup.getId())) return;
@@ -336,6 +349,17 @@ class ClientVersioningManagerImpl implements ClientVersioningManager, Client,
 				MAJOR_VERSION, c);
 	}
 
+	@Nullable
+	private LatestUpdates findLatestUpdates(Transaction txn, ContactId c)
+			throws DbException, FormatException {
+		Contact contact = db.getContact(txn, c);
+		Group g = getContactGroup(contact);
+		// Contact may be in the process of being added or removed, so
+		// contact group may not exist
+		if (!db.containsGroup(txn, g.getId())) return null;
+		return findLatestUpdates(txn, g.getId());
+	}
+
 	private LatestUpdates findLatestUpdates(Transaction txn, GroupId g)
 			throws DbException, FormatException {
 		Map<MessageId, BdfDictionary> metadata =

bramble-core/src/main/resources/bridges

@@ -1,4 +1,5 @@
 Bridge obfs4 78.46.188.239:37356 5A2D2F4158D0453E00C7C176978D3F41D69C45DB cert=3c0SwxpOisbohNxEc4tb875RVW8eOu1opRTVXJhafaKA/PNNtI7ElQIVOVZg1AdL5bxGCw iat-mode=0
 Bridge obfs4 52.15.78.72:9443 02069A3C5362476936B62BA6F5ACC41ABD573A9B cert=ijYG/OKc7kqu2YzKNFfeXN7/BG2BOgfEP2KyYEiGDQthnHbsOiTWHeIG0WJVW+BckzDgKw iat-mode=0
 Bridge obfs4 13.58.29.242:9443 0C58939A77DA6B6B29D4B5236A75865659607AE0 cert=OylWIEHb/ezpq1zWxW0sgKRn+9ARH2eOcQOZ8/Gew+4l+oKOhQ2jUX/Y+FSl61JorXZUWA iat-mode=0
-Bridge obfs4 45.33.37.112:9443 60A609BB4ABE8D46E634AE81ED29ADAB7776B399 cert=t5v19WmNv5Sc2YPNr8RQids365W7MY8zJwQVkOxBjUMFomMWARDzsbYpcWLLcw0J9Gm+BQ iat-mode=0
+Bridge obfs4 45.33.37.112:9443 60A609BB4ABE8D46E634AE81ED29ADAB7776B399 cert=t5v19WmNv5Sc2YPNr8RQids365W7MY8zJwQVkOxBjUMFomMWARDzsbYpcWLLcw0J9Gm+BQ iat-mode=0
+Bridge meek_lite 0.0.2.0:2 97700DFE9F483596DDA6264C4D7DF7641E1E39CE url=https://meek.azureedge.net/ front=ajax.aspnetcdn.com

bramble-core/src/test/java/org/briarproject/bramble/util/ByteUtilsTest.java

@@ -1,135 +1,118 @@
 package org.briarproject.bramble.util;
 
-import org.briarproject.bramble.api.FormatException;
 import org.briarproject.bramble.test.BrambleTestCase;
 import org.junit.Test;
 
-import java.util.Random;
-
-import static java.util.Arrays.fill;
 import static org.briarproject.bramble.util.ByteUtils.MAX_16_BIT_UNSIGNED;
 import static org.briarproject.bramble.util.ByteUtils.MAX_32_BIT_UNSIGNED;
-import static org.briarproject.bramble.util.ByteUtils.MAX_VARINT_BYTES;
-import static org.briarproject.bramble.util.ByteUtils.getVarIntBytes;
-import static org.briarproject.bramble.util.ByteUtils.readUint16;
-import static org.briarproject.bramble.util.ByteUtils.readUint32;
-import static org.briarproject.bramble.util.ByteUtils.readUint64;
-import static org.briarproject.bramble.util.ByteUtils.readVarInt;
-import static org.briarproject.bramble.util.ByteUtils.writeUint16;
-import static org.briarproject.bramble.util.ByteUtils.writeUint32;
-import static org.briarproject.bramble.util.ByteUtils.writeUint64;
-import static org.briarproject.bramble.util.ByteUtils.writeVarInt;
-import static org.briarproject.bramble.util.StringUtils.fromHexString;
-import static org.briarproject.bramble.util.StringUtils.toHexString;
 import static org.junit.Assert.assertEquals;
 import static org.junit.Assert.fail;
 
-@SuppressWarnings("ResultOfMethodCallIgnored")
 public class ByteUtilsTest extends BrambleTestCase {
 
 	@Test
 	public void testReadUint16() {
-		byte[] b = fromHexString("00000000");
-		assertEquals(0, readUint16(b, 1));
-		b = fromHexString("00000100");
-		assertEquals(1, readUint16(b, 1));
-		b = fromHexString("007FFF00");
-		assertEquals(Short.MAX_VALUE, readUint16(b, 1));
-		b = fromHexString("00FFFF00");
-		assertEquals(65535, readUint16(b, 1));
+		byte[] b = StringUtils.fromHexString("00000000");
+		assertEquals(0, ByteUtils.readUint16(b, 1));
+		b = StringUtils.fromHexString("00000100");
+		assertEquals(1, ByteUtils.readUint16(b, 1));
+		b = StringUtils.fromHexString("007FFF00");
+		assertEquals(Short.MAX_VALUE, ByteUtils.readUint16(b, 1));
+		b = StringUtils.fromHexString("00FFFF00");
+		assertEquals(65535, ByteUtils.readUint16(b, 1));
 	}
 
 	@Test(expected = IllegalArgumentException.class)
 	public void testReadUint16ValidatesArguments1() {
-		readUint16(new byte[1], 0);
+		ByteUtils.readUint16(new byte[1], 0);
 	}
 
 	@Test(expected = IllegalArgumentException.class)
 	public void testReadUint16ValidatesArguments2() {
-		readUint16(new byte[2], 1);
+		ByteUtils.readUint16(new byte[2], 1);
 	}
 
 	@Test
 	public void testReadUint32() {
-		byte[] b = fromHexString("000000000000");
-		assertEquals(0, readUint32(b, 1));
-		b = fromHexString("000000000100");
-		assertEquals(1, readUint32(b, 1));
-		b = fromHexString("007FFFFFFF00");
-		assertEquals(Integer.MAX_VALUE, readUint32(b, 1));
-		b = fromHexString("00FFFFFFFF00");
-		assertEquals(4294967295L, readUint32(b, 1));
+		byte[] b = StringUtils.fromHexString("000000000000");
+		assertEquals(0, ByteUtils.readUint32(b, 1));
+		b = StringUtils.fromHexString("000000000100");
+		assertEquals(1, ByteUtils.readUint32(b, 1));
+		b = StringUtils.fromHexString("007FFFFFFF00");
+		assertEquals(Integer.MAX_VALUE, ByteUtils.readUint32(b, 1));
+		b = StringUtils.fromHexString("00FFFFFFFF00");
+		assertEquals(4294967295L, ByteUtils.readUint32(b, 1));
 	}
 
 	@Test(expected = IllegalArgumentException.class)
 	public void testReadUint32ValidatesArguments1() {
-		readUint32(new byte[3], 0);
+		ByteUtils.readUint32(new byte[3], 0);
 	}
 
 	@Test(expected = IllegalArgumentException.class)
 	public void testReadUint32ValidatesArguments2() {
-		readUint32(new byte[4], 1);
+		ByteUtils.readUint32(new byte[4], 1);
 	}
 
 	@Test
 	public void testReadUint64() {
-		byte[] b = fromHexString("00000000000000000000");
-		assertEquals(0L, readUint64(b, 1));
-		b = fromHexString("00000000000000000100");
-		assertEquals(1L, readUint64(b, 1));
-		b = fromHexString("007FFFFFFFFFFFFFFF00");
-		assertEquals(Long.MAX_VALUE, readUint64(b, 1));
-		b = fromHexString("00800000000000000000");
-		assertEquals(Long.MIN_VALUE, readUint64(b, 1));
-		b = fromHexString("00FFFFFFFFFFFFFFFF00");
-		assertEquals(-1L, readUint64(b, 1));
+		byte[] b = StringUtils.fromHexString("00000000000000000000");
+		assertEquals(0L, ByteUtils.readUint64(b, 1));
+		b = StringUtils.fromHexString("00000000000000000100");
+		assertEquals(1L, ByteUtils.readUint64(b, 1));
+		b = StringUtils.fromHexString("007FFFFFFFFFFFFFFF00");
+		assertEquals(Long.MAX_VALUE, ByteUtils.readUint64(b, 1));
+		b = StringUtils.fromHexString("00800000000000000000");
+		assertEquals(Long.MIN_VALUE, ByteUtils.readUint64(b, 1));
+		b = StringUtils.fromHexString("00FFFFFFFFFFFFFFFF00");
+		assertEquals(-1L, ByteUtils.readUint64(b, 1));
 	}
 
 	@Test(expected = IllegalArgumentException.class)
 	public void testReadUint64ValidatesArguments1() {
-		readUint64(new byte[7], 0);
+		ByteUtils.readUint64(new byte[7], 0);
 	}
 
 	@Test(expected = IllegalArgumentException.class)
 	public void testReadUint64ValidatesArguments2() {
-		readUint64(new byte[8], 1);
+		ByteUtils.readUint64(new byte[8], 1);
 	}
 
 	@Test
 	public void testWriteUint16() {
 		byte[] b = new byte[4];
-		writeUint16(0, b, 1);
-		assertEquals("00000000", toHexString(b));
-		writeUint16(1, b, 1);
-		assertEquals("00000100", toHexString(b));
-		writeUint16(Short.MAX_VALUE, b, 1);
-		assertEquals("007FFF00", toHexString(b));
-		writeUint16(MAX_16_BIT_UNSIGNED, b, 1);
-		assertEquals("00FFFF00", toHexString(b));
+		ByteUtils.writeUint16(0, b, 1);
+		assertEquals("00000000", StringUtils.toHexString(b));
+		ByteUtils.writeUint16(1, b, 1);
+		assertEquals("00000100", StringUtils.toHexString(b));
+		ByteUtils.writeUint16(Short.MAX_VALUE, b, 1);
+		assertEquals("007FFF00", StringUtils.toHexString(b));
+		ByteUtils.writeUint16(MAX_16_BIT_UNSIGNED, b, 1);
+		assertEquals("00FFFF00", StringUtils.toHexString(b));
 	}
 
 	@Test
 	public void testWriteUint16ValidatesArguments() {
 		try {
-			writeUint16(0, new byte[1], 0);
+			ByteUtils.writeUint16(0, new byte[1], 0);
 			fail();
 		} catch (IllegalArgumentException expected) {
 			// Expected
 		}
 		try {
-			writeUint16(0, new byte[2], 1);
+			ByteUtils.writeUint16(0, new byte[2], 1);
 			fail();
 		} catch (IllegalArgumentException expected) {
 			// Expected
 		}
 		try {
-			writeUint16(-1, new byte[2], 0);
+			ByteUtils.writeUint16(-1, new byte[2], 0);
 			fail();
 		} catch (IllegalArgumentException expected) {
 			// Expected
 		}
 		try {
-			writeUint16(MAX_16_BIT_UNSIGNED + 1, new byte[2], 0);
+			ByteUtils.writeUint16(MAX_16_BIT_UNSIGNED + 1, new byte[2], 0);
 			fail();
 		} catch (IllegalArgumentException expected) {
 			// Expected
@@ -139,38 +122,38 @@ public class ByteUtilsTest extends BrambleTestCase {
 	@Test
 	public void testWriteUint32() {
 		byte[] b = new byte[6];
-		writeUint32(0, b, 1);
-		assertEquals("000000000000", toHexString(b));
-		writeUint32(1, b, 1);
-		assertEquals("000000000100", toHexString(b));
-		writeUint32(Integer.MAX_VALUE, b, 1);
-		assertEquals("007FFFFFFF00", toHexString(b));
-		writeUint32(MAX_32_BIT_UNSIGNED, b, 1);
-		assertEquals("00FFFFFFFF00", toHexString(b));
+		ByteUtils.writeUint32(0, b, 1);
+		assertEquals("000000000000", StringUtils.toHexString(b));
+		ByteUtils.writeUint32(1, b, 1);
+		assertEquals("000000000100", StringUtils.toHexString(b));
+		ByteUtils.writeUint32(Integer.MAX_VALUE, b, 1);
+		assertEquals("007FFFFFFF00", StringUtils.toHexString(b));
+		ByteUtils.writeUint32(MAX_32_BIT_UNSIGNED, b, 1);
+		assertEquals("00FFFFFFFF00", StringUtils.toHexString(b));
 	}
 
 	@Test
 	public void testWriteUint32ValidatesArguments() {
 		try {
-			writeUint32(0, new byte[3], 0);
+			ByteUtils.writeUint32(0, new byte[3], 0);
 			fail();
 		} catch (IllegalArgumentException expected) {
 			// Expected
 		}
 		try {
-			writeUint32(0, new byte[4], 1);
+			ByteUtils.writeUint32(0, new byte[4], 1);
 			fail();
 		} catch (IllegalArgumentException expected) {
 			// Expected
 		}
 		try {
-			writeUint32(-1, new byte[4], 0);
+			ByteUtils.writeUint32(-1, new byte[4], 0);
 			fail();
 		} catch (IllegalArgumentException expected) {
 			// Expected
 		}
 		try {
-			writeUint32(MAX_32_BIT_UNSIGNED + 1, new byte[4], 0);
+			ByteUtils.writeUint32(MAX_32_BIT_UNSIGNED + 1, new byte[4], 0);
 			fail();
 		} catch (IllegalArgumentException expected) {
 			// Expected
@@ -180,30 +163,30 @@ public class ByteUtilsTest extends BrambleTestCase {
 	@Test
 	public void testWriteUint64() {
 		byte[] b = new byte[10];
-		writeUint64(0, b, 1);
-		assertEquals("00000000000000000000", toHexString(b));
-		writeUint64(1, b, 1);
-		assertEquals("00000000000000000100", toHexString(b));
-		writeUint64(Long.MAX_VALUE, b, 1);
-		assertEquals("007FFFFFFFFFFFFFFF00", toHexString(b));
+		ByteUtils.writeUint64(0, b, 1);
+		assertEquals("00000000000000000000", StringUtils.toHexString(b));
+		ByteUtils.writeUint64(1, b, 1);
+		assertEquals("00000000000000000100", StringUtils.toHexString(b));
+		ByteUtils.writeUint64(Long.MAX_VALUE, b, 1);
+		assertEquals("007FFFFFFFFFFFFFFF00", StringUtils.toHexString(b));
 	}
 
 	@Test
 	public void testWriteUint64ValidatesArguments() {
 		try {
-			writeUint64(0, new byte[7], 0);
+			ByteUtils.writeUint64(0, new byte[7], 0);
 			fail();
 		} catch (IllegalArgumentException expected) {
 			// Expected
 		}
 		try {
-			writeUint64(0, new byte[8], 1);
+			ByteUtils.writeUint64(0, new byte[8], 1);
 			fail();
 		} catch (IllegalArgumentException expected) {
 			// Expected
 		}
 		try {
-			writeUint64(-1, new byte[8], 0);
+			ByteUtils.writeUint64(-1, new byte[8], 0);
 			fail();
 		} catch (IllegalArgumentException expected) {
 			// Expected
@@ -211,170 +194,17 @@ public class ByteUtilsTest extends BrambleTestCase {
 	}
 
 	@Test
-	public void testGetVarIntBytesToWrite() {
-		assertEquals(1, getVarIntBytes(0));
-		assertEquals(1, getVarIntBytes(0x7F)); // Max 7-bit int
-		assertEquals(2, getVarIntBytes(0x7F + 1));
-		assertEquals(2, getVarIntBytes(0x3FFF)); // Max 14-bit int
-		assertEquals(3, getVarIntBytes(0x3FFF + 1));
-		assertEquals(3, getVarIntBytes(0x1FFFFF)); // Max 21-bit int
-		assertEquals(4, getVarIntBytes(0x1FFFFF + 1));
-		assertEquals(4, getVarIntBytes(0xFFFFFFF)); // Max 28-bit int
-		assertEquals(5, getVarIntBytes(0xFFFFFFF + 1));
-		assertEquals(5, getVarIntBytes(0x7FFFFFFFFL)); // Max 35-bit int
-		assertEquals(6, getVarIntBytes(0x7FFFFFFFFL + 1));
-		assertEquals(6, getVarIntBytes(0x3FFFFFFFFFFL)); // Max 42-bit int
-		assertEquals(7, getVarIntBytes(0x3FFFFFFFFFFL + 1));
-		assertEquals(7, getVarIntBytes(0x1FFFFFFFFFFFFL)); // Max 49-bit int
-		assertEquals(8, getVarIntBytes(0x1FFFFFFFFFFFFL + 1));
-		assertEquals(8, getVarIntBytes(0xFFFFFFFFFFFFFFL)); // Max 56-bit int
-		assertEquals(9, getVarIntBytes(0xFFFFFFFFFFFFFFL + 1));
-		assertEquals(9, getVarIntBytes(0x7FFFFFFFFFFFFFFFL)); // Max 63-bit int
-		assertEquals(MAX_VARINT_BYTES, getVarIntBytes(Long.MAX_VALUE)); // Same
-	}
-
-	@Test
-	public void testWriteVarInt() {
-		testWriteVarInt(0, 1, "00");
-		testWriteVarInt(1, 1, "01");
-		testWriteVarInt(0x7F, 1, "7F"); // Max 7-bit int
-		testWriteVarInt(0x7F + 1, 2, "8100");
-		testWriteVarInt(0x3FFF, 2, "FF7F"); // Max 14-bit int
-		testWriteVarInt(0x3FFF + 1, 3, "818000");
-		testWriteVarInt(0x1FFFFF, 3, "FFFF7F"); // Max 21-bit int
-		testWriteVarInt(0x1FFFFF + 1, 4, "81808000");
-		testWriteVarInt(0xFFFFFFF, 4, "FFFFFF7F"); // Max 28-bit int
-		testWriteVarInt(0xFFFFFFF + 1, 5, "8180808000");
-		testWriteVarInt(0x7FFFFFFFFL, 5, "FFFFFFFF7F"); // Max 35-bit int
-		testWriteVarInt(0x7FFFFFFFFL + 1, 6, "818080808000");
-		testWriteVarInt(0x3FFFFFFFFFFL, 6, "FFFFFFFFFF7F"); // Max 42-bit int
-		testWriteVarInt(0x3FFFFFFFFFFL + 1, 7, "81808080808000");
-		testWriteVarInt(0x1FFFFFFFFFFFFL, 7, "FFFFFFFFFFFF7F"); // Max 49
-		testWriteVarInt(0x1FFFFFFFFFFFFL + 1, 8, "8180808080808000");
-		testWriteVarInt(0xFFFFFFFFFFFFFFL, 8, "FFFFFFFFFFFFFF7F"); // Max 56
-		testWriteVarInt(0xFFFFFFFFFFFFFFL + 1, 9, "818080808080808000");
-		testWriteVarInt(0x7FFFFFFFFFFFFFFFL, 9, "FFFFFFFFFFFFFFFF7F"); // Max 63
-		testWriteVarInt(Long.MAX_VALUE, MAX_VARINT_BYTES, "FFFFFFFFFFFFFFFF7F");
-	}
-
-	private void testWriteVarInt(long src, int len, String destHex) {
-		byte[] dest = new byte[9];
-		assertEquals(len, writeVarInt(src, dest, 0));
-		assertEquals(destHex, toHexString(dest).substring(0, len * 2));
-	}
-
-	@Test
-	public void testGetVarIntBytesToRead() throws FormatException {
-		testGetVarIntBytesToRead(1, "00", 0);
-		testGetVarIntBytesToRead(1, "01", 0);
-		testGetVarIntBytesToRead(1, "7F", 0); // Max 7-bit int
-		testGetVarIntBytesToRead(2, "8100", 0);
-		testGetVarIntBytesToRead(2, "FF7F", 0); // Max 14-bit int
-		testGetVarIntBytesToRead(3, "818000", 0);
-		testGetVarIntBytesToRead(3, "FFFF7F", 0); // Max 21-bit int
-		testGetVarIntBytesToRead(4, "81808000", 0);
-		testGetVarIntBytesToRead(4, "FFFFFF7F", 0); // Max 28-bit int
-		testGetVarIntBytesToRead(5, "8180808000", 0);
-		testGetVarIntBytesToRead(5, "FFFFFFFF7F", 0); // Max 35-bit int
-		testGetVarIntBytesToRead(6, "818080808000", 0);
-		testGetVarIntBytesToRead(6, "FFFFFFFFFF7F", 0); // Max 42-bit int
-		testGetVarIntBytesToRead(7, "81808080808000", 0);
-		testGetVarIntBytesToRead(7, "FFFFFFFFFFFF7F", 0); // Max 49-bit int
-		testGetVarIntBytesToRead(8, "8180808080808000", 0);
-		testGetVarIntBytesToRead(8, "FFFFFFFFFFFFFF7F", 0); // Max 56-bit int
-		testGetVarIntBytesToRead(9, "818080808080808000", 0);
-		testGetVarIntBytesToRead(9, "FFFFFFFFFFFFFFFF7F", 0); // Max 63-bit int
-		// Start at offset, ignore trailing data
-		testGetVarIntBytesToRead(1, "FF0000", 1);
-		testGetVarIntBytesToRead(9, "00FFFFFFFFFFFFFFFF7F00", 1);
-	}
-
-	private void testGetVarIntBytesToRead(int len, String srcHex, int offset)
-			throws FormatException {
-		assertEquals(len, getVarIntBytes(fromHexString(srcHex), offset));
-	}
-
-	@Test(expected = FormatException.class)
-	public void testGetVarIntBytesToReadThrowsExceptionAtEndOfInput()
-			throws FormatException {
-		byte[] src = new byte[MAX_VARINT_BYTES - 1];
-		fill(src, (byte) 0xFF);
-		// Reaches end of input without finding lowered continuation flag
-		getVarIntBytes(src, 0);
-	}
-
-	@Test(expected = FormatException.class)
-	public void testGetVarIntBytesToReadThrowsExceptionAfterNineBytes()
-			throws FormatException {
-		byte[] src = new byte[MAX_VARINT_BYTES];
-		fill(src, (byte) 0xFF);
-		// Reaches max length without finding lowered continuation flag
-		getVarIntBytes(src, 0);
-	}
-
-	@Test
-	public void testReadVarInt() throws FormatException {
-		testReadVarInt(0, "00", 0);
-		testReadVarInt(1, "01", 0);
-		testReadVarInt(0x7F, "7F", 0); // Max 7-bit int
-		testReadVarInt(0x7F + 1, "8100", 0);
-		testReadVarInt(0x3FFF, "FF7F", 0); // Max 14-bit int
-		testReadVarInt(0x3FFF + 1, "818000", 0);
-		testReadVarInt(0x1FFFFF, "FFFF7F", 0); // Max 21-bit int
-		testReadVarInt(0x1FFFFF + 1, "81808000", 0);
-		testReadVarInt(0xFFFFFFF, "FFFFFF7F", 0); // Max 28-bit int
-		testReadVarInt(0xFFFFFFF + 1, "8180808000", 0);
-		testReadVarInt(0x7FFFFFFFFL, "FFFFFFFF7F", 0); // Max 35-bit int
-		testReadVarInt(0x7FFFFFFFFL + 1, "818080808000", 0);
-		testReadVarInt(0x3FFFFFFFFFFL, "FFFFFFFFFF7F", 0); // Max 42-bit int
-		testReadVarInt(0x3FFFFFFFFFFL + 1, "81808080808000", 0);
-		testReadVarInt(0x1FFFFFFFFFFFFL, "FFFFFFFFFFFF7F", 0); // Max 49-bit int
-		testReadVarInt(0x1FFFFFFFFFFFFL + 1, "8180808080808000", 0);
-		testReadVarInt(0xFFFFFFFFFFFFFFL, "FFFFFFFFFFFFFF7F", 0); // Max 56
-		testReadVarInt(0xFFFFFFFFFFFFFFL + 1, "818080808080808000", 0);
-		testReadVarInt(0x7FFFFFFFFFFFFFFFL, "FFFFFFFFFFFFFFFF7F", 0); // Max 63
-		testReadVarInt(Long.MAX_VALUE, "FFFFFFFFFFFFFFFF7F", 0);
-		// Start at offset, ignore trailing data
-		testReadVarInt(0, "FF0000", 1);
-		testReadVarInt(Long.MAX_VALUE, "00FFFFFFFFFFFFFFFF7F00", 1);
-	}
-
-	private void testReadVarInt(long dest, String srcHex, int offset)
-			throws FormatException {
-		assertEquals(dest, readVarInt(fromHexString(srcHex), offset));
-	}
-
-	@Test(expected = FormatException.class)
-	public void testReadVarIntThrowsExceptionAtEndOfInput()
-			throws FormatException {
-		byte[] src = new byte[MAX_VARINT_BYTES - 1];
-		fill(src, (byte) 0xFF);
-		// Reaches end of input without finding lowered continuation flag
-		readVarInt(src, 0);
-	}
-
-	@Test(expected = FormatException.class)
-	public void testReadVarIntThrowsExceptionAfterNineBytes()
-			throws FormatException {
-		byte[] src = new byte[MAX_VARINT_BYTES];
-		fill(src, (byte) 0xFF);
-		// Reaches max length without finding lowered continuation flag
-		readVarInt(src, 0);
-	}
-
-	@Test
-	public void testWriteAndReadVarInt() throws FormatException {
-		Random random = new Random();
-		int padding = 10;
-		byte[] buf = new byte[MAX_VARINT_BYTES + padding];
-		for (int i = 0; i < 1000; i++) {
-			long src = random.nextLong() & 0x7FFFFFFFFFFFFFFFL; // Non-negative
-			int offset = random.nextInt(padding);
-			int len = getVarIntBytes(src);
-			assertEquals(len, writeVarInt(src, buf, offset));
-			assertEquals(len, getVarIntBytes(buf, offset));
-			assertEquals(src, readVarInt(buf, offset));
-			fill(buf, (byte) 0);
+	public void testReadUint() {
+		byte[] b = new byte[1];
+		b[0] = (byte) 128;
+		for (int i = 0; i < 8; i++) {
+			assertEquals(1 << i, ByteUtils.readUint(b, i + 1));
+		}
+		b = new byte[2];
+		for (int i = 0; i < 65535; i++) {
+			ByteUtils.writeUint16(i, b, 0);
+			assertEquals(i, ByteUtils.readUint(b, 16));
+			assertEquals(i >> 1, ByteUtils.readUint(b, 15));
 		}
 	}
 }

bramble-core/src/test/java/org/briarproject/bramble/versioning/ClientVersioningManagerImplTest.java

@@ -8,6 +8,7 @@ import org.briarproject.bramble.api.data.BdfDictionary;
 import org.briarproject.bramble.api.data.BdfEntry;
 import org.briarproject.bramble.api.data.BdfList;
 import org.briarproject.bramble.api.db.DatabaseComponent;
+import org.briarproject.bramble.api.db.DbException;
 import org.briarproject.bramble.api.db.Metadata;
 import org.briarproject.bramble.api.db.Transaction;
 import org.briarproject.bramble.api.sync.ClientId;
@@ -43,6 +44,7 @@ import static org.briarproject.bramble.util.StringUtils.getRandomString;
 import static org.briarproject.bramble.versioning.ClientVersioningConstants.GROUP_KEY_CONTACT_ID;
 import static org.briarproject.bramble.versioning.ClientVersioningConstants.MSG_KEY_LOCAL;
 import static org.briarproject.bramble.versioning.ClientVersioningConstants.MSG_KEY_UPDATE_VERSION;
+import static org.junit.Assert.assertEquals;
 import static org.junit.Assert.assertFalse;
 
 public class ClientVersioningManagerImplTest extends BrambleMockTestCase {
@@ -657,4 +659,327 @@ public class ClientVersioningManagerImplTest extends BrambleMockTestCase {
 		c.registerClient(clientId, 123, 234, hook);
 		assertFalse(c.incomingMessage(txn, newRemoteUpdate, new Metadata()));
 	}
+
+	@Test
+	public void testReturnsInvisibleIfContactGroupDoesNotExist()
+			throws Exception {
+		expectGetContactGroup(false);
+
+		ClientVersioningManagerImpl c = createInstance();
+		assertEquals(INVISIBLE, c.getClientVisibility(txn, contact.getId(),
+				clientId, 123));
+	}
+
+	@Test
+	public void testReturnsInvisibleIfNoRemoteUpdateExists() throws Exception {
+		MessageId localUpdateId = new MessageId(getRandomId());
+		BdfDictionary localUpdateMeta = BdfDictionary.of(
+				new BdfEntry(MSG_KEY_UPDATE_VERSION, 1L),
+				new BdfEntry(MSG_KEY_LOCAL, true));
+
+		expectGetContactGroup(true);
+		context.checking(new Expectations() {{
+			oneOf(clientHelper).getMessageMetadataAsDictionary(txn,
+					contactGroup.getId());
+			will(returnValue(singletonMap(localUpdateId, localUpdateMeta)));
+		}});
+
+		ClientVersioningManagerImpl c = createInstance();
+		assertEquals(INVISIBLE, c.getClientVisibility(txn, contact.getId(),
+				clientId, 123));
+	}
+
+	@Test(expected = DbException.class)
+	public void testThrowsExceptionIfNoLocalUpdateExists() throws Exception {
+		MessageId remoteUpdateId = new MessageId(getRandomId());
+		BdfDictionary remoteUpdateMeta = BdfDictionary.of(
+				new BdfEntry(MSG_KEY_UPDATE_VERSION, 1L),
+				new BdfEntry(MSG_KEY_LOCAL, false));
+
+		expectGetContactGroup(true);
+		context.checking(new Expectations() {{
+			oneOf(clientHelper).getMessageMetadataAsDictionary(txn,
+					contactGroup.getId());
+			will(returnValue(singletonMap(remoteUpdateId, remoteUpdateMeta)));
+		}});
+
+		ClientVersioningManagerImpl c = createInstance();
+		c.getClientVisibility(txn, contact.getId(), clientId, 123);
+	}
+
+	@Test
+	public void testReturnsInvisibleIfClientNotSupportedLocally()
+			throws Exception {
+		MessageId localUpdateId = new MessageId(getRandomId());
+		BdfDictionary localUpdateMeta = BdfDictionary.of(
+				new BdfEntry(MSG_KEY_UPDATE_VERSION, 1L),
+				new BdfEntry(MSG_KEY_LOCAL, true));
+		MessageId remoteUpdateId = new MessageId(getRandomId());
+		BdfDictionary remoteUpdateMeta = BdfDictionary.of(
+				new BdfEntry(MSG_KEY_UPDATE_VERSION, 1L),
+				new BdfEntry(MSG_KEY_LOCAL, false));
+		Map<MessageId, BdfDictionary> messageMetadata = new HashMap<>();
+		messageMetadata.put(localUpdateId, localUpdateMeta);
+		messageMetadata.put(remoteUpdateId, remoteUpdateMeta);
+		// The client is supported remotely but not locally
+		BdfList localUpdateBody = BdfList.of(new BdfList(), 1L);
+		BdfList remoteUpdateBody = BdfList.of(BdfList.of(
+				BdfList.of(clientId.getString(), 123, 234, false)), 1L);
+
+		expectGetContactGroup(true);
+		context.checking(new Expectations() {{
+			oneOf(clientHelper).getMessageMetadataAsDictionary(txn,
+					contactGroup.getId());
+			will(returnValue(messageMetadata));
+			oneOf(clientHelper).getMessageAsList(txn, localUpdateId);
+			will(returnValue(localUpdateBody));
+			oneOf(clientHelper).getMessageAsList(txn, remoteUpdateId);
+			will(returnValue(remoteUpdateBody));
+		}});
+
+		ClientVersioningManagerImpl c = createInstance();
+		assertEquals(INVISIBLE, c.getClientVisibility(txn, contact.getId(),
+				clientId, 123));
+	}
+
+	@Test
+	public void testReturnsInvisibleIfClientNotSupportedRemotely()
+			throws Exception {
+		MessageId localUpdateId = new MessageId(getRandomId());
+		BdfDictionary localUpdateMeta = BdfDictionary.of(
+				new BdfEntry(MSG_KEY_UPDATE_VERSION, 1L),
+				new BdfEntry(MSG_KEY_LOCAL, true));
+		MessageId remoteUpdateId = new MessageId(getRandomId());
+		BdfDictionary remoteUpdateMeta = BdfDictionary.of(
+				new BdfEntry(MSG_KEY_UPDATE_VERSION, 1L),
+				new BdfEntry(MSG_KEY_LOCAL, false));
+		Map<MessageId, BdfDictionary> messageMetadata = new HashMap<>();
+		messageMetadata.put(localUpdateId, localUpdateMeta);
+		messageMetadata.put(remoteUpdateId, remoteUpdateMeta);
+		// The client is supported locally but not remotely
+		BdfList localUpdateBody = BdfList.of(BdfList.of(
+				BdfList.of(clientId.getString(), 123, 234, false)), 1L);
+		BdfList remoteUpdateBody = BdfList.of(new BdfList(), 1L);
+
+		expectGetContactGroup(true);
+		context.checking(new Expectations() {{
+			oneOf(clientHelper).getMessageMetadataAsDictionary(txn,
+					contactGroup.getId());
+			will(returnValue(messageMetadata));
+			oneOf(clientHelper).getMessageAsList(txn, localUpdateId);
+			will(returnValue(localUpdateBody));
+			oneOf(clientHelper).getMessageAsList(txn, remoteUpdateId);
+			will(returnValue(remoteUpdateBody));
+		}});
+
+		ClientVersioningManagerImpl c = createInstance();
+		assertEquals(INVISIBLE, c.getClientVisibility(txn, contact.getId(),
+				clientId, 123));
+	}
+
+	@Test
+	public void testReturnsVisibleIfClientNotActiveRemotely() throws Exception {
+		MessageId localUpdateId = new MessageId(getRandomId());
+		BdfDictionary localUpdateMeta = BdfDictionary.of(
+				new BdfEntry(MSG_KEY_UPDATE_VERSION, 1L),
+				new BdfEntry(MSG_KEY_LOCAL, true));
+		MessageId remoteUpdateId = new MessageId(getRandomId());
+		BdfDictionary remoteUpdateMeta = BdfDictionary.of(
+				new BdfEntry(MSG_KEY_UPDATE_VERSION, 1L),
+				new BdfEntry(MSG_KEY_LOCAL, false));
+		Map<MessageId, BdfDictionary> messageMetadata = new HashMap<>();
+		messageMetadata.put(localUpdateId, localUpdateMeta);
+		messageMetadata.put(remoteUpdateId, remoteUpdateMeta);
+		// The client is supported locally and remotely but not active
+		BdfList localUpdateBody = BdfList.of(BdfList.of(
+				BdfList.of(clientId.getString(), 123, 234, false)), 1L);
+		BdfList remoteUpdateBody = BdfList.of(BdfList.of(
+				BdfList.of(clientId.getString(), 123, 234, false)), 1L);
+
+		expectGetContactGroup(true);
+		context.checking(new Expectations() {{
+			oneOf(clientHelper).getMessageMetadataAsDictionary(txn,
+					contactGroup.getId());
+			will(returnValue(messageMetadata));
+			oneOf(clientHelper).getMessageAsList(txn, localUpdateId);
+			will(returnValue(localUpdateBody));
+			oneOf(clientHelper).getMessageAsList(txn, remoteUpdateId);
+			will(returnValue(remoteUpdateBody));
+		}});
+
+		ClientVersioningManagerImpl c = createInstance();
+		assertEquals(VISIBLE, c.getClientVisibility(txn, contact.getId(),
+				clientId, 123));
+	}
+
+	@Test
+	public void testReturnsSharedIfClientActiveRemotely() throws Exception {
+		MessageId localUpdateId = new MessageId(getRandomId());
+		BdfDictionary localUpdateMeta = BdfDictionary.of(
+				new BdfEntry(MSG_KEY_UPDATE_VERSION, 1L),
+				new BdfEntry(MSG_KEY_LOCAL, true));
+		MessageId remoteUpdateId = new MessageId(getRandomId());
+		BdfDictionary remoteUpdateMeta = BdfDictionary.of(
+				new BdfEntry(MSG_KEY_UPDATE_VERSION, 1L),
+				new BdfEntry(MSG_KEY_LOCAL, false));
+		Map<MessageId, BdfDictionary> messageMetadata = new HashMap<>();
+		messageMetadata.put(localUpdateId, localUpdateMeta);
+		messageMetadata.put(remoteUpdateId, remoteUpdateMeta);
+		// The client is supported locally and remotely and active
+		BdfList localUpdateBody = BdfList.of(BdfList.of(
+				BdfList.of(clientId.getString(), 123, 234, true)), 1L);
+		BdfList remoteUpdateBody = BdfList.of(BdfList.of(
+				BdfList.of(clientId.getString(), 123, 234, true)), 1L);
+
+		expectGetContactGroup(true);
+		context.checking(new Expectations() {{
+			oneOf(clientHelper).getMessageMetadataAsDictionary(txn,
+					contactGroup.getId());
+			will(returnValue(messageMetadata));
+			oneOf(clientHelper).getMessageAsList(txn, localUpdateId);
+			will(returnValue(localUpdateBody));
+			oneOf(clientHelper).getMessageAsList(txn, remoteUpdateId);
+			will(returnValue(remoteUpdateBody));
+		}});
+
+		ClientVersioningManagerImpl c = createInstance();
+		assertEquals(SHARED, c.getClientVisibility(txn, contact.getId(),
+				clientId, 123));
+	}
+
+	@Test
+	public void testReturnsNegativeIfContactGroupDoesNotExist()
+			throws Exception {
+		expectGetContactGroup(false);
+
+		ClientVersioningManagerImpl c = createInstance();
+		assertEquals(-1, c.getClientMinorVersion(txn, contact.getId(),
+				clientId, 123));
+	}
+
+	@Test
+	public void testReturnsNegativeIfNoRemoteUpdateExists() throws Exception {
+		MessageId localUpdateId = new MessageId(getRandomId());
+		BdfDictionary localUpdateMeta = BdfDictionary.of(
+				new BdfEntry(MSG_KEY_UPDATE_VERSION, 1L),
+				new BdfEntry(MSG_KEY_LOCAL, true));
+
+		expectGetContactGroup(true);
+		context.checking(new Expectations() {{
+			oneOf(clientHelper).getMessageMetadataAsDictionary(txn,
+					contactGroup.getId());
+			will(returnValue(singletonMap(localUpdateId, localUpdateMeta)));
+		}});
+
+		ClientVersioningManagerImpl c = createInstance();
+		assertEquals(-1, c.getClientMinorVersion(txn, contact.getId(),
+				clientId, 123));
+	}
+
+	@Test
+	public void testReturnsNegativeIfClientNotSupportedRemotely()
+			throws Exception {
+		MessageId localUpdateId = new MessageId(getRandomId());
+		BdfDictionary localUpdateMeta = BdfDictionary.of(
+				new BdfEntry(MSG_KEY_UPDATE_VERSION, 1L),
+				new BdfEntry(MSG_KEY_LOCAL, true));
+		MessageId remoteUpdateId = new MessageId(getRandomId());
+		BdfDictionary remoteUpdateMeta = BdfDictionary.of(
+				new BdfEntry(MSG_KEY_UPDATE_VERSION, 1L),
+				new BdfEntry(MSG_KEY_LOCAL, false));
+		Map<MessageId, BdfDictionary> messageMetadata = new HashMap<>();
+		messageMetadata.put(localUpdateId, localUpdateMeta);
+		messageMetadata.put(remoteUpdateId, remoteUpdateMeta);
+		// The client is not supported remotely
+		BdfList remoteUpdateBody = BdfList.of(new BdfList(), 1L);
+
+		expectGetContactGroup(true);
+		context.checking(new Expectations() {{
+			oneOf(clientHelper).getMessageMetadataAsDictionary(txn,
+					contactGroup.getId());
+			will(returnValue(messageMetadata));
+			oneOf(clientHelper).getMessageAsList(txn, remoteUpdateId);
+			will(returnValue(remoteUpdateBody));
+		}});
+
+		ClientVersioningManagerImpl c = createInstance();
+		assertEquals(-1, c.getClientMinorVersion(txn, contact.getId(),
+				clientId, 123));
+	}
+
+	@Test
+	public void testReturnsMinorVersionIfClientNotActiveRemotely()
+			throws Exception {
+		MessageId localUpdateId = new MessageId(getRandomId());
+		BdfDictionary localUpdateMeta = BdfDictionary.of(
+				new BdfEntry(MSG_KEY_UPDATE_VERSION, 1L),
+				new BdfEntry(MSG_KEY_LOCAL, true));
+		MessageId remoteUpdateId = new MessageId(getRandomId());
+		BdfDictionary remoteUpdateMeta = BdfDictionary.of(
+				new BdfEntry(MSG_KEY_UPDATE_VERSION, 1L),
+				new BdfEntry(MSG_KEY_LOCAL, false));
+		Map<MessageId, BdfDictionary> messageMetadata = new HashMap<>();
+		messageMetadata.put(localUpdateId, localUpdateMeta);
+		messageMetadata.put(remoteUpdateId, remoteUpdateMeta);
+		// The client is supported remotely but not active
+		BdfList remoteUpdateBody = BdfList.of(BdfList.of(
+				BdfList.of(clientId.getString(), 123, 234, false)), 1L);
+
+		expectGetContactGroup(true);
+		context.checking(new Expectations() {{
+			oneOf(clientHelper).getMessageMetadataAsDictionary(txn,
+					contactGroup.getId());
+			will(returnValue(messageMetadata));
+			oneOf(clientHelper).getMessageAsList(txn, remoteUpdateId);
+			will(returnValue(remoteUpdateBody));
+		}});
+
+		ClientVersioningManagerImpl c = createInstance();
+		assertEquals(234, c.getClientMinorVersion(txn, contact.getId(),
+				clientId, 123));
+	}
+
+	@Test
+	public void testReturnsMinorVersionIfClientActiveRemotely()
+			throws Exception {
+		MessageId localUpdateId = new MessageId(getRandomId());
+		BdfDictionary localUpdateMeta = BdfDictionary.of(
+				new BdfEntry(MSG_KEY_UPDATE_VERSION, 1L),
+				new BdfEntry(MSG_KEY_LOCAL, true));
+		MessageId remoteUpdateId = new MessageId(getRandomId());
+		BdfDictionary remoteUpdateMeta = BdfDictionary.of(
+				new BdfEntry(MSG_KEY_UPDATE_VERSION, 1L),
+				new BdfEntry(MSG_KEY_LOCAL, false));
+		Map<MessageId, BdfDictionary> messageMetadata = new HashMap<>();
+		messageMetadata.put(localUpdateId, localUpdateMeta);
+		messageMetadata.put(remoteUpdateId, remoteUpdateMeta);
+		// The client is supported remotely and active
+		BdfList remoteUpdateBody = BdfList.of(BdfList.of(
+				BdfList.of(clientId.getString(), 123, 234, true)), 1L);
+
+		expectGetContactGroup(true);
+		context.checking(new Expectations() {{
+			oneOf(clientHelper).getMessageMetadataAsDictionary(txn,
+					contactGroup.getId());
+			will(returnValue(messageMetadata));
+			oneOf(clientHelper).getMessageAsList(txn, remoteUpdateId);
+			will(returnValue(remoteUpdateBody));
+		}});
+
+		ClientVersioningManagerImpl c = createInstance();
+		assertEquals(234, c.getClientMinorVersion(txn, contact.getId(),
+				clientId, 123));
+	}
+
+	private void expectGetContactGroup(boolean exists) throws Exception {
+		context.checking(new Expectations() {{
+			oneOf(db).getContact(txn, contact.getId());
+			will(returnValue(contact));
+			oneOf(contactGroupFactory).createContactGroup(CLIENT_ID,
+					MAJOR_VERSION, contact);
+			will(returnValue(contactGroup));
+			oneOf(db).containsGroup(txn, contactGroup.getId());
+			will(returnValue(exists));
+		}});
+	}
 }

bramble-java/build.gradle

@@ -16,7 +16,7 @@ dependencies {
 	implementation fileTree(dir: 'libs', include: '*.jar')
 	implementation 'net.java.dev.jna:jna:4.5.2'
 	implementation 'net.java.dev.jna:jna-platform:4.5.2'
-	tor 'org.briarproject:tor:0.3.4.8@zip'
+	tor 'org.briarproject:tor:0.3.5.8@zip'
 	tor 'org.briarproject:obfs4proxy:0.0.7@zip'
 
 	annotationProcessor 'com.google.dagger:dagger-compiler:2.19'

bramble-java/src/test/java/org/briarproject/bramble/plugin/tor/BridgeTest.java

@@ -44,7 +44,7 @@ public class BridgeTest extends BrambleTestCase {
 	public static Iterable<String> data() {
 		BrambleJavaIntegrationTestComponent component =
 				DaggerBrambleJavaIntegrationTestComponent.builder().build();
-		return component.getCircumventionProvider().getBridges();
+		return component.getCircumventionProvider().getBridges(false);
 	}
 
 	private final static long TIMEOUT = SECONDS.toMillis(30);
@@ -104,7 +104,12 @@ public class BridgeTest extends BrambleTestCase {
 			}
 
 			@Override
-			public List<String> getBridges() {
+			public boolean needsMeek(String countryCode) {
+				return false;
+			}
+
+			@Override
+			public List<String> getBridges(boolean useMeek) {
 				return singletonList(bridge);
 			}
 		};

bramble-java/witness.gradle

@@ -21,7 +21,7 @@ dependencyVerification {
         'org.apache.ant:ant:1.9.4:ant-1.9.4.jar:649ae0730251de07b8913f49286d46bba7b92d47c5f332610aa426c4f02161d8',
         'org.beanshell:bsh:1.3.0:bsh-1.3.0.jar:9b04edc75d19db54f1b4e8b5355e9364384c6cf71eb0a1b9724c159d779879f8',
         'org.briarproject:obfs4proxy:0.0.7:obfs4proxy-0.0.7.zip:5b2f693262ce43a7e130f7cc7d5d1617925330640a2eb6d71085e95df8ee0642',
-        'org.briarproject:tor:0.3.4.8:tor-0.3.4.8.zip:bc0158c34002f471a4fe14a6a481816c918eb520a220bb027f64be902beb757f',
+        'org.briarproject:tor:0.3.5.8:tor-0.3.5.8.zip:96e83391f01984f28669235fc02fbb0243140a2b3b2c73aeffd0042c8d3ced18',
         'org.checkerframework:checker-compat-qual:2.5.3:checker-compat-qual-2.5.3.jar:d76b9afea61c7c082908023f0cbc1427fab9abd2df915c8b8a3e7a509bccbc6d',
         'org.codehaus.mojo:animal-sniffer-annotations:1.14:animal-sniffer-annotations-1.14.jar:2068320bd6bad744c3673ab048f67e30bef8f518996fa380033556600669905d',
         'org.hamcrest:hamcrest-core:1.3:hamcrest-core-1.3.jar:66fdef91e9739348df7a096aa384a5685f4e875584cce89386a7a47251c4d8e9',

briar-android/build.gradle

@@ -22,8 +22,8 @@ android {
 	defaultConfig {
 		minSdkVersion 15
 		targetSdkVersion 26
-		versionCode 10105
-		versionName "1.1.5"
+		versionCode 10106
+		versionName "1.1.6"
 		applicationId "org.briarproject.briar.android"
 		buildConfigField "String", "GitHash",
 				"\"${getStdout(['git', 'rev-parse', '--short=7', 'HEAD'], 'No commit hash')}\""
@@ -116,7 +116,7 @@ dependencies {
 	implementation 'info.guardianproject.trustedintents:trustedintents:0.2'
 	implementation 'de.hdodenhof:circleimageview:2.2.0'
 	implementation 'com.google.zxing:core:3.3.3'
-	implementation 'uk.co.samuelwall:material-tap-target-prompt:2.12.4'
+	implementation 'uk.co.samuelwall:material-tap-target-prompt:2.14.0'
 	implementation 'com.vanniktech:emoji-google:0.5.1'
 	def glideVersion = '4.8.0'
 	implementation("com.github.bumptech.glide:glide:$glideVersion") {
@@ -134,7 +134,7 @@ dependencies {
 	testImplementation project(path: ':bramble-core', configuration: 'testOutput')
 	testImplementation 'org.robolectric:robolectric:4.0.1'
 	testImplementation 'org.robolectric:shadows-support-v4:3.3.2'
-	testImplementation 'org.mockito:mockito-core:2.13.0'
+	testImplementation 'org.mockito:mockito-core:2.19.0'
 	testImplementation 'junit:junit:4.12'
 	testImplementation "org.jmock:jmock:2.8.2"
 	testImplementation "org.jmock:jmock-junit4:2.8.2"

briar-android/src/androidTestOfficial/java/org/briarproject/briar/android/conversation/AttachmentControllerIntegrationTest.java

@@ -0,0 +1,279 @@
+package org.briarproject.briar.android.conversation;
+
+import android.content.res.AssetManager;
+import android.support.test.InstrumentationRegistry;
+import android.support.test.runner.AndroidJUnit4;
+
+import org.briarproject.bramble.api.UniqueId;
+import org.briarproject.bramble.api.sync.MessageId;
+import org.briarproject.briar.api.messaging.Attachment;
+import org.briarproject.briar.api.messaging.AttachmentHeader;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+
+import java.io.IOException;
+import java.io.InputStream;
+import java.net.URL;
+import java.util.Random;
+
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertFalse;
+import static org.junit.Assert.assertTrue;
+
+@RunWith(AndroidJUnit4.class)
+public class AttachmentControllerIntegrationTest {
+
+	private static final String smallKitten =
+			"https://upload.wikimedia.org/wikipedia/commons/thumb/0/06/Kitten_in_Rizal_Park%2C_Manila.jpg/160px-Kitten_in_Rizal_Park%2C_Manila.jpg";
+	private static final String originalKitten =
+			"https://upload.wikimedia.org/wikipedia/commons/0/06/Kitten_in_Rizal_Park%2C_Manila.jpg";
+	private static final String pngKitten =
+			"https://upload.wikimedia.org/wikipedia/commons/c/c8/Young_cat.png";
+	private static final String uberGif =
+			"https://raw.githubusercontent.com/fuzzdb-project/fuzzdb/master/attack/file-upload/malicious-images/uber.gif";
+	private static final String lottaPixel =
+			"https://raw.githubusercontent.com/fuzzdb-project/fuzzdb/master/attack/file-upload/malicious-images/lottapixel.jpg";
+	private static final String imageIoCrash =
+			"https://www.landaire.net/img/crasher.png";
+	private static final String gimpCrash =
+			"https://gitlab.gnome.org/GNOME/gimp/uploads/75f5b7ed3b09b3f1c13f1f65bffe784f/31153c919d3aa634e8e6cff82219fe7352dd8a37.png";
+	private static final String optiPngAfl =
+			"https://sourceforge.net/p/optipng/bugs/64/attachment/test.gif";
+	private static final String librawError =
+			"https://www.libraw.org/sites/libraw.org/files/P1010671.JPG";
+
+	private final AttachmentDimensions dimensions = new AttachmentDimensions(
+			100, 50, 200, 75, 300
+	);
+	private final MessageId msgId = new MessageId(getRandomId());
+
+	private final AttachmentController controller =
+			new AttachmentController(null, dimensions);
+
+	@Test
+	public void testSmallJpegImage() throws Exception {
+		AttachmentHeader h = new AttachmentHeader(msgId, "image/jpeg");
+		InputStream is = getUrlInputStream(smallKitten);
+		Attachment a = new Attachment(is);
+		AttachmentItem item = controller.getAttachmentItem(h, a, true);
+		assertEquals(msgId, item.getMessageId());
+		assertEquals(160, item.getWidth());
+		assertEquals(240, item.getHeight());
+		assertEquals(160, item.getThumbnailWidth());
+		assertEquals(240, item.getThumbnailHeight());
+		assertEquals("image/jpeg", item.getMimeType());
+		assertEquals("jpg", item.getExtension());
+		assertFalse(item.hasError());
+	}
+
+	@Test
+	public void testBigJpegImage() throws Exception {
+		AttachmentHeader h = new AttachmentHeader(msgId, "image/jpeg");
+		InputStream is = getUrlInputStream(originalKitten);
+		Attachment a = new Attachment(is);
+		AttachmentItem item = controller.getAttachmentItem(h, a, true);
+		assertEquals(msgId, item.getMessageId());
+		assertEquals(1728, item.getWidth());
+		assertEquals(2592, item.getHeight());
+		assertEquals(dimensions.maxWidth, item.getThumbnailWidth());
+		assertEquals(dimensions.maxHeight, item.getThumbnailHeight());
+		assertEquals("image/jpeg", item.getMimeType());
+		assertEquals("jpg", item.getExtension());
+		assertFalse(item.hasError());
+	}
+
+	@Test
+	public void testSmallPngImage() throws Exception {
+		AttachmentHeader h = new AttachmentHeader(msgId, "image/png");
+		InputStream is = getUrlInputStream(pngKitten);
+		Attachment a = new Attachment(is);
+		AttachmentItem item = controller.getAttachmentItem(h, a, true);
+		assertEquals(msgId, item.getMessageId());
+		assertEquals(737, item.getWidth());
+		assertEquals(510, item.getHeight());
+		assertEquals(dimensions.maxWidth, item.getThumbnailWidth());
+		assertEquals(138, item.getThumbnailHeight());
+		assertEquals("image/png", item.getMimeType());
+		assertEquals("png", item.getExtension());
+		assertFalse(item.hasError());
+	}
+
+	@Test
+	public void testUberGif() throws Exception {
+		AttachmentHeader h = new AttachmentHeader(msgId, "image/jpeg");
+		InputStream is = getUrlInputStream(uberGif);
+		Attachment a = new Attachment(is);
+		AttachmentItem item = controller.getAttachmentItem(h, a, true);
+		assertEquals(1, item.getWidth());
+		assertEquals(1, item.getHeight());
+		assertEquals(dimensions.minHeight, item.getThumbnailWidth());
+		assertEquals(dimensions.minHeight, item.getThumbnailHeight());
+		assertEquals("image/gif", item.getMimeType());
+		assertEquals("gif", item.getExtension());
+		assertFalse(item.hasError());
+	}
+
+	@Test
+	public void testLottaPixels() throws Exception {
+		AttachmentHeader h = new AttachmentHeader(msgId, "image/jpeg");
+		InputStream is = getUrlInputStream(lottaPixel);
+		Attachment a = new Attachment(is);
+		AttachmentItem item = controller.getAttachmentItem(h, a, true);
+		assertEquals(64250, item.getWidth());
+		assertEquals(64250, item.getHeight());
+		assertEquals(dimensions.maxWidth, item.getThumbnailWidth());
+		assertEquals(dimensions.maxWidth, item.getThumbnailHeight());
+		assertEquals("image/jpeg", item.getMimeType());
+		assertEquals("jpg", item.getExtension());
+		assertFalse(item.hasError());
+	}
+
+	@Test
+	public void testImageIoCrash() throws Exception {
+		AttachmentHeader h = new AttachmentHeader(msgId, "image/jpeg");
+		InputStream is = getUrlInputStream(imageIoCrash);
+		Attachment a = new Attachment(is);
+		AttachmentItem item = controller.getAttachmentItem(h, a, true);
+		assertEquals(1184, item.getWidth());
+		assertEquals(448, item.getHeight());
+		assertEquals(dimensions.maxWidth, item.getThumbnailWidth());
+		assertEquals(dimensions.minHeight, item.getThumbnailHeight());
+		assertEquals("image/png", item.getMimeType());
+		assertEquals("png", item.getExtension());
+		assertFalse(item.hasError());
+	}
+
+	@Test
+	public void testGimpCrash() throws Exception {
+		AttachmentHeader h = new AttachmentHeader(msgId, "image/jpeg");
+		InputStream is = getUrlInputStream(gimpCrash);
+		Attachment a = new Attachment(is);
+		AttachmentItem item = controller.getAttachmentItem(h, a, true);
+		assertEquals(1, item.getWidth());
+		assertEquals(1, item.getHeight());
+		assertEquals(dimensions.minHeight, item.getThumbnailWidth());
+		assertEquals(dimensions.minHeight, item.getThumbnailHeight());
+		assertEquals("image/gif", item.getMimeType());
+		assertEquals("gif", item.getExtension());
+		assertFalse(item.hasError());
+	}
+
+	@Test
+	public void testOptiPngAfl() throws Exception {
+		AttachmentHeader h = new AttachmentHeader(msgId, "image/jpeg");
+		InputStream is = getUrlInputStream(optiPngAfl);
+		Attachment a = new Attachment(is);
+		AttachmentItem item = controller.getAttachmentItem(h, a, true);
+		assertEquals(32, item.getWidth());
+		assertEquals(32, item.getHeight());
+		assertEquals(dimensions.minHeight, item.getThumbnailWidth());
+		assertEquals(dimensions.minHeight, item.getThumbnailHeight());
+		assertEquals("image/gif", item.getMimeType());
+		assertEquals("gif", item.getExtension());
+		assertFalse(item.hasError());
+	}
+
+	@Test
+	public void testLibrawError() throws Exception {
+		AttachmentHeader h = new AttachmentHeader(msgId, "image/jpeg");
+		InputStream is = getUrlInputStream(librawError);
+		Attachment a = new Attachment(is);
+		AttachmentItem item = controller.getAttachmentItem(h, a, true);
+		assertTrue(item.hasError());
+	}
+
+	@Test
+	public void testSmallAnimatedGifMaxDimensions() throws Exception {
+		AttachmentHeader h = new AttachmentHeader(msgId, "image/gif");
+		InputStream is = getAssetInputStream("animated.gif");
+		Attachment a = new Attachment(is);
+		AttachmentItem item = controller.getAttachmentItem(h, a, true);
+		assertEquals(65535, item.getWidth());
+		assertEquals(65535, item.getHeight());
+		assertEquals(dimensions.maxWidth, item.getThumbnailWidth());
+		assertEquals(dimensions.maxWidth, item.getThumbnailHeight());
+		assertEquals("image/gif", item.getMimeType());
+		assertEquals("gif", item.getExtension());
+		assertFalse(item.hasError());
+	}
+
+	@Test
+	public void testSmallAnimatedGifHugeDimensions() throws Exception {
+		AttachmentHeader h = new AttachmentHeader(msgId, "image/gif");
+		InputStream is = getAssetInputStream("animated2.gif");
+		Attachment a = new Attachment(is);
+		AttachmentItem item = controller.getAttachmentItem(h, a, true);
+		assertEquals(10000, item.getWidth());
+		assertEquals(10000, item.getHeight());
+		assertEquals(dimensions.maxWidth, item.getThumbnailWidth());
+		assertEquals(dimensions.maxWidth, item.getThumbnailHeight());
+		assertEquals("image/gif", item.getMimeType());
+		assertEquals("gif", item.getExtension());
+		assertFalse(item.hasError());
+	}
+
+	@Test
+	public void testSmallGifLargeDimensions() throws Exception {
+		AttachmentHeader h = new AttachmentHeader(msgId, "image/gif");
+		InputStream is = getAssetInputStream("error_large.gif");
+		Attachment a = new Attachment(is);
+		AttachmentItem item = controller.getAttachmentItem(h, a, true);
+		assertEquals(16384, item.getWidth());
+		assertEquals(16384, item.getHeight());
+		assertEquals(dimensions.maxWidth, item.getThumbnailWidth());
+		assertEquals(dimensions.maxWidth, item.getThumbnailHeight());
+		assertEquals("image/gif", item.getMimeType());
+		assertEquals("gif", item.getExtension());
+		assertFalse(item.hasError());
+	}
+
+	@Test
+	public void testHighError() throws Exception {
+		AttachmentHeader h = new AttachmentHeader(msgId, "image/jpeg");
+		InputStream is = getAssetInputStream("error_high.jpg");
+		Attachment a = new Attachment(is);
+		AttachmentItem item = controller.getAttachmentItem(h, a, true);
+		assertEquals(1, item.getWidth());
+		assertEquals(10000, item.getHeight());
+		assertEquals(dimensions.minWidth, item.getThumbnailWidth());
+		assertEquals(dimensions.maxHeight, item.getThumbnailHeight());
+		assertEquals("image/jpeg", item.getMimeType());
+		assertEquals("jpg", item.getExtension());
+		assertFalse(item.hasError());
+	}
+
+	@Test
+	public void testWideError() throws Exception {
+		AttachmentHeader h = new AttachmentHeader(msgId, "image/jpeg");
+		InputStream is = getAssetInputStream("error_wide.jpg");
+		Attachment a = new Attachment(is);
+		AttachmentItem item = controller.getAttachmentItem(h, a, true);
+		assertEquals(1920, item.getWidth());
+		assertEquals(1, item.getHeight());
+		assertEquals(dimensions.maxWidth, item.getThumbnailWidth());
+		assertEquals(dimensions.minHeight, item.getThumbnailHeight());
+		assertEquals("image/jpeg", item.getMimeType());
+		assertEquals("jpg", item.getExtension());
+		assertFalse(item.hasError());
+	}
+
+	private InputStream getUrlInputStream(String url) throws IOException {
+		return new URL(url).openStream();
+	}
+
+	private InputStream getAssetInputStream(String name) throws IOException {
+		AssetManager assets = InstrumentationRegistry.getContext().getAssets();
+		return assets.open(name);
+	}
+
+	public static byte[] getRandomBytes(int length) {
+		byte[] b = new byte[length];
+		new Random().nextBytes(b);
+		return b;
+	}
+
+	public static byte[] getRandomId() {
+		return getRandomBytes(UniqueId.LENGTH);
+	}
+
+}

briar-android/src/androidTestOfficial/java/org/briarproject/briar/android/conversation/ConversationActivityNotSignedInTest.java

@@ -0,0 +1,38 @@
+package org.briarproject.briar.android.conversation;
+
+import android.content.Context;
+import android.content.Intent;
+import android.support.test.rule.ActivityTestRule;
+import android.support.test.runner.AndroidJUnit4;
+
+import org.briarproject.briar.R;
+import org.junit.Rule;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+
+import static android.support.test.InstrumentationRegistry.getInstrumentation;
+import static android.support.test.espresso.Espresso.onView;
+import static android.support.test.espresso.matcher.ViewMatchers.isDisplayed;
+import static android.support.test.espresso.matcher.ViewMatchers.withText;
+import static org.briarproject.briar.android.ViewActions.waitUntilMatches;
+import static org.briarproject.briar.android.conversation.ConversationActivity.CONTACT_ID;
+
+@RunWith(AndroidJUnit4.class)
+public class ConversationActivityNotSignedInTest {
+
+	@Rule
+	public ActivityTestRule<ConversationActivity> testRule =
+			new ActivityTestRule<>(ConversationActivity.class, false, false);
+
+	@Test
+	public void openWithoutSignedIn() {
+		Context targetContext = getInstrumentation().getTargetContext();
+		Intent intent = new Intent(targetContext, ConversationActivity.class);
+		intent.putExtra(CONTACT_ID, 1);
+		testRule.launchActivity(intent);
+
+		onView(withText(R.string.sign_in_button))
+				.perform(waitUntilMatches(isDisplayed()));
+	}
+
+}

briar-android/src/main/AndroidManifest.xml

@@ -1,6 +1,7 @@
 <?xml version="1.0" encoding="utf-8"?>
 <manifest
 	package="org.briarproject.briar"
+	xmlns:tools="http://schemas.android.com/tools"
 	xmlns:android="http://schemas.android.com/apk/res/android">
 
 	<uses-feature android:name="android.hardware.bluetooth" android:required="false"/>
@@ -17,9 +18,11 @@
 	<uses-permission android:name="android.permission.USE_FINGERPRINT"/>
 	<uses-permission android:name="android.permission.VIBRATE" />
 	<uses-permission android:name="android.permission.WAKE_LOCK" />
+	<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
 	<uses-permission-sdk-23 android:name="android.permission.ACCESS_COARSE_LOCATION" />
 	<uses-permission-sdk-23 android:name="android.permission.REQUEST_IGNORE_BATTERY_OPTIMIZATIONS"/>
 	<uses-permission-sdk-23 android:name="android.permission.USE_BIOMETRIC" />
+	<uses-permission-sdk-23 android:name="android.permission.FOREGROUND_SERVICE" />
 
 	<application
 		android:name="org.briarproject.briar.android.BriarApplicationImpl"
@@ -28,7 +31,8 @@
 		android:label="@string/app_name"
 		android:logo="@mipmap/ic_launcher_round"
 		android:supportsRtl="true"
-		android:theme="@style/BriarTheme">
+		android:theme="@style/BriarTheme"
+		tools:ignore="GoogleAppIndexingWarning">
 
 		<receiver
 			android:name="org.briarproject.briar.android.login.SignInReminderReceiver"
@@ -116,7 +120,7 @@
 		<activity
 			android:name=".android.conversation.ImageActivity"
 			android:parentActivityName="org.briarproject.briar.android.conversation.ConversationActivity"
-			android:theme="@style/BriarTheme.Transparent.NoActionBar">
+			android:theme="@style/BriarTheme.ActionBarOverlay">
 			<meta-data
 				android:name="android.support.PARENT_ACTIVITY"
 				android:value="org.briarproject.briar.android.conversation.ConversationActivity"/>
@@ -154,7 +158,7 @@
 				android:value="org.briarproject.briar.android.navdrawer.NavDrawerActivity"/>
 		</activity>
 
-			<activity
+		<activity
 			android:name="org.briarproject.briar.android.privategroup.memberlist.GroupMemberListActivity"
 			android:label="@string/groups_member_list"
 			android:parentActivityName="org.briarproject.briar.android.privategroup.conversation.GroupActivity"
@@ -397,7 +401,7 @@
 		<activity
 			android:name="org.briarproject.briar.android.panic.PanicResponderActivity"
 			android:noHistory="true"
-			android:theme="@style/Theme.AppCompat.NoActionBar">
+			android:theme="@style/TranslucentTheme">
 			<!-- this can never have launchMode singleTask or singleInstance! -->
 			<intent-filter>
 				<action android:name="info.guardianproject.panic.action.TRIGGER"/>
@@ -407,12 +411,12 @@
 
 		<activity
 			android:name="org.briarproject.briar.android.logout.ExitActivity"
-			android:theme="@style/Theme.AppCompat.NoActionBar">
+			android:theme="@android:style/Theme.NoDisplay">
 		</activity>
 
 		<activity
 			android:name=".android.logout.HideUiActivity"
-			android:theme="@style/Theme.AppCompat.NoActionBar">
+			android:theme="@android:style/Theme.NoDisplay">
 		</activity>
 
 		<activity

briar-android/src/main/java/org/briarproject/briar/android/AndroidComponent.java

@@ -32,7 +32,7 @@ import org.briarproject.briar.BriarCoreModule;
 import org.briarproject.briar.android.conversation.glide.BriarModelLoader;
 import org.briarproject.briar.android.login.SignInReminderReceiver;
 import org.briarproject.briar.android.reporting.BriarReportSender;
-import org.briarproject.briar.android.view.TextInputView;
+import org.briarproject.briar.android.view.EmojiTextInputView;
 import org.briarproject.briar.api.android.AndroidNotificationManager;
 import org.briarproject.briar.api.android.DozeWatchdog;
 import org.briarproject.briar.api.android.LockManager;
@@ -169,7 +169,7 @@ public interface AndroidComponent
 
 	void inject(NotificationCleanupService notificationCleanupService);
 
-	void inject(TextInputView textInputView);
+	void inject(EmojiTextInputView textInputView);
 
 	void inject(BriarModelLoader briarModelLoader);
 

briar-android/src/main/java/org/briarproject/briar/android/AndroidNotificationManagerImpl.java

@@ -231,7 +231,7 @@ class AndroidNotificationManagerImpl implements AndroidNotificationManager,
 			showForumPostNotification(f.getGroupId());
 		} else if (e instanceof BlogPostAddedEvent) {
 			BlogPostAddedEvent b = (BlogPostAddedEvent) e;
-			showBlogPostNotification(b.getGroupId());
+			if (!b.isLocal()) showBlogPostNotification(b.getGroupId());
 		} else if (e instanceof IntroductionSucceededEvent) {
 			showIntroductionNotification();
 		}

briar-android/src/main/java/org/briarproject/briar/android/BackgroundMonitor.java

@@ -0,0 +1,54 @@
+package org.briarproject.briar.android;
+
+import android.app.Activity;
+import android.app.Application.ActivityLifecycleCallbacks;
+import android.os.Bundle;
+
+import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
+
+import java.util.concurrent.atomic.AtomicInteger;
+
+import javax.annotation.Nullable;
+import javax.annotation.concurrent.ThreadSafe;
+
+@ThreadSafe
+@NotNullByDefault
+class BackgroundMonitor implements ActivityLifecycleCallbacks {
+
+	private final AtomicInteger foregroundActivities = new AtomicInteger(0);
+
+	boolean isRunningInBackground() {
+		return foregroundActivities.get() == 0;
+	}
+
+	@Override
+	public void onActivityCreated(Activity a, @Nullable Bundle state) {
+	}
+
+	@Override
+	public void onActivityStarted(Activity a) {
+		foregroundActivities.incrementAndGet();
+	}
+
+	@Override
+	public void onActivityResumed(Activity a) {
+	}
+
+	@Override
+	public void onActivityPaused(Activity a) {
+	}
+
+	@Override
+	public void onActivityStopped(Activity a) {
+		foregroundActivities.decrementAndGet();
+	}
+
+	@Override
+	public void onActivitySaveInstanceState(Activity a,
+			@Nullable Bundle outState) {
+	}
+
+	@Override
+	public void onActivityDestroyed(Activity a) {
+	}
+}

briar-android/src/main/java/org/briarproject/briar/android/BriarApplication.java

@@ -16,4 +16,6 @@ public interface BriarApplication {
 	AndroidComponent getApplicationComponent();
 
 	SharedPreferences getDefaultSharedPreferences();
+
+	boolean isRunningInBackground();
 }

briar-android/src/main/java/org/briarproject/briar/android/BriarApplicationImpl.java

@@ -1,5 +1,7 @@
 package org.briarproject.briar.android;
 
+import android.app.ActivityManager;
+import android.app.ActivityManager.RunningAppProcessInfo;
 import android.app.Application;
 import android.content.Context;
 import android.content.SharedPreferences;
@@ -30,6 +32,8 @@ import java.util.logging.Handler;
 import java.util.logging.LogRecord;
 import java.util.logging.Logger;
 
+import static android.app.ActivityManager.RunningAppProcessInfo.IMPORTANCE_FOREGROUND;
+import static android.os.Build.VERSION.SDK_INT;
 import static java.util.logging.Level.FINE;
 import static java.util.logging.Level.INFO;
 import static org.acra.ReportField.ANDROID_VERSION;
@@ -79,6 +83,7 @@ public class BriarApplicationImpl extends Application
 			Logger.getLogger(BriarApplicationImpl.class.getName());
 
 	private final CachingLogHandler logHandler = new CachingLogHandler();
+	private final BackgroundMonitor backgroundMonitor = new BackgroundMonitor();
 
 	private AndroidComponent applicationComponent;
 	private volatile SharedPreferences prefs;
@@ -115,6 +120,9 @@ public class BriarApplicationImpl extends Application
 
 		applicationComponent = createApplicationComponent();
 		EmojiManager.install(new GoogleEmojiProvider());
+
+		if (SDK_INT < 16)
+			registerActivityLifecycleCallbacks(backgroundMonitor);
 	}
 
 	protected AndroidComponent createApplicationComponent() {
@@ -173,4 +181,15 @@ public class BriarApplicationImpl extends Application
 	public SharedPreferences getDefaultSharedPreferences() {
 		return prefs;
 	}
+
+	@Override
+	public boolean isRunningInBackground() {
+		if (SDK_INT >= 16) {
+			RunningAppProcessInfo info = new RunningAppProcessInfo();
+			ActivityManager.getMyMemoryState(info);
+			return (info.importance != IMPORTANCE_FOREGROUND);
+		} else {
+			return backgroundMonitor.isRunningInBackground();
+		}
+	}
 }

briar-android/src/main/java/org/briarproject/briar/android/BriarService.java

@@ -1,7 +1,5 @@
 package org.briarproject.briar.android;
 
-import android.app.ActivityManager;
-import android.app.ActivityManager.RunningAppProcessInfo;
 import android.app.Notification;
 import android.app.NotificationChannel;
 import android.app.NotificationManager;
@@ -35,7 +33,6 @@ import java.util.logging.Logger;
 import javax.annotation.Nullable;
 import javax.inject.Inject;
 
-import static android.app.ActivityManager.RunningAppProcessInfo.IMPORTANCE_FOREGROUND;
 import static android.app.NotificationManager.IMPORTANCE_DEFAULT;
 import static android.app.NotificationManager.IMPORTANCE_NONE;
 import static android.app.PendingIntent.FLAG_UPDATE_CURRENT;
@@ -74,6 +71,7 @@ public class BriarService extends Service {
 
 	@Nullable
 	private BroadcastReceiver receiver = null;
+	private BriarApplication app;
 
 	@Inject
 	AndroidNotificationManager notificationManager;
@@ -93,8 +91,8 @@ public class BriarService extends Service {
 	public void onCreate() {
 		super.onCreate();
 
-		BriarApplication application = (BriarApplication) getApplication();
-		application.getApplicationComponent().inject(this);
+		app = (BriarApplication) getApplication();
+		app.getApplicationComponent().inject(this);
 
 		LOG.info("Created");
 		if (created.getAndSet(true)) {
@@ -220,8 +218,8 @@ public class BriarService extends Service {
 	public void onLowMemory() {
 		super.onLowMemory();
 		LOG.warning("Memory is low");
-		// Clear the UI - this is done in onTrimMemory() if SDK_INT >= 16
-		if (SDK_INT < 16) hideUi();
+		// If we're not in the foreground, clear the UI to save memory
+		if (app.isRunningInBackground()) hideUi();
 	}
 
 	@Override
@@ -235,20 +233,16 @@ public class BriarService extends Service {
 			LOG.info("Trim memory: near middle of LRU list");
 		} else if (level == TRIM_MEMORY_COMPLETE) {
 			LOG.info("Trim memory: near end of LRU list");
-		} else if (SDK_INT >= 16) {
-			if (level == TRIM_MEMORY_RUNNING_MODERATE) {
-				LOG.info("Trim memory: running moderately low");
-			} else if (level == TRIM_MEMORY_RUNNING_LOW) {
-				LOG.info("Trim memory: running low");
-			} else if (level == TRIM_MEMORY_RUNNING_CRITICAL) {
-				LOG.info("Trim memory: running critically low");
-				// If we're not in the foreground, clear the UI to save memory
-				RunningAppProcessInfo info = new RunningAppProcessInfo();
-				ActivityManager.getMyMemoryState(info);
-				if (info.importance != IMPORTANCE_FOREGROUND) hideUi();
-			} else if (LOG.isLoggable(INFO)) {
-				LOG.info("Trim memory: unknown level " + level);
-			}
+		} else if (level == TRIM_MEMORY_RUNNING_MODERATE) {
+			LOG.info("Trim memory: running moderately low");
+		} else if (level == TRIM_MEMORY_RUNNING_LOW) {
+			LOG.info("Trim memory: running low");
+		} else if (level == TRIM_MEMORY_RUNNING_CRITICAL) {
+			// This level may be received if SDK_INT < 16, although the
+			// constant isn't declared until API level 16
+			LOG.warning("Trim memory: running critically low");
+			// If we're not in the foreground, clear the UI to save memory
+			if (app.isRunningInBackground()) hideUi();
 		} else if (LOG.isLoggable(INFO)) {
 			LOG.info("Trim memory: unknown level " + level);
 		}

briar-android/src/main/java/org/briarproject/briar/android/StartupFailureActivity.java

@@ -3,22 +3,29 @@ package org.briarproject.briar.android;
 import android.app.NotificationManager;
 import android.content.Intent;
 import android.os.Bundle;
+import android.support.annotation.NonNull;
+import android.support.annotation.Nullable;
 
+import org.briarproject.bramble.api.nullsafety.MethodsNotNullByDefault;
+import org.briarproject.bramble.api.nullsafety.ParametersNotNullByDefault;
 import org.briarproject.briar.R;
 import org.briarproject.briar.android.activity.ActivityComponent;
 import org.briarproject.briar.android.activity.BaseActivity;
 import org.briarproject.briar.android.fragment.BaseFragment.BaseFragmentListener;
 import org.briarproject.briar.android.fragment.ErrorFragment;
 
+import static java.util.Objects.requireNonNull;
 import static org.briarproject.bramble.api.lifecycle.LifecycleManager.StartResult;
 import static org.briarproject.briar.android.BriarService.EXTRA_NOTIFICATION_ID;
 import static org.briarproject.briar.android.BriarService.EXTRA_START_RESULT;
 
+@MethodsNotNullByDefault
+@ParametersNotNullByDefault
 public class StartupFailureActivity extends BaseActivity implements
 		BaseFragmentListener {
 
 	@Override
-	public void onCreate(Bundle state) {
+	public void onCreate(@Nullable Bundle state) {
 		super.onCreate(state);
 
 		setContentView(R.layout.activity_fragment_container);
@@ -38,7 +45,7 @@ public class StartupFailureActivity extends BaseActivity implements
 		// cancel notification
 		if (notificationId > -1) {
 			Object o = getSystemService(NOTIFICATION_SERVICE);
-			NotificationManager nm = (NotificationManager) o;
+			NotificationManager nm = (NotificationManager) requireNonNull(o);
 			nm.cancel(notificationId);
 		}
 
@@ -66,7 +73,7 @@ public class StartupFailureActivity extends BaseActivity implements
 	}
 
 	@Override
-	public void runOnDbThread(Runnable runnable) {
+	public void runOnDbThread(@NonNull Runnable runnable) {
 		throw new AssertionError("Deprecated and should not be used");
 	}
 

briar-android/src/main/java/org/briarproject/briar/android/TestingConstants.java

@@ -30,4 +30,10 @@ public interface TestingConstants {
 	long EXPIRY_DATE = IS_DEBUG_BUILD || IS_BETA_BUILD ?
 			BuildConfig.BuildTimestamp + 90 * 24 * 60 * 60 * 1000L :
 			Long.MAX_VALUE;
+
+	/**
+	 * Feature flag for enabling image attachments.
+	 */
+	boolean FEATURE_FLAG_IMAGE_ATTACHMENTS = IS_DEBUG_BUILD;
+
 }

briar-android/src/main/java/org/briarproject/briar/android/activity/ActivityComponent.java

@@ -20,6 +20,7 @@ import org.briarproject.briar.android.contact.ContactModule;
 import org.briarproject.briar.android.conversation.AliasDialogFragment;
 import org.briarproject.briar.android.conversation.ConversationActivity;
 import org.briarproject.briar.android.conversation.ImageActivity;
+import org.briarproject.briar.android.conversation.ImageFragment;
 import org.briarproject.briar.android.forum.CreateForumActivity;
 import org.briarproject.briar.android.forum.ForumActivity;
 import org.briarproject.briar.android.forum.ForumListFragment;
@@ -30,7 +31,6 @@ import org.briarproject.briar.android.introduction.IntroductionActivity;
 import org.briarproject.briar.android.introduction.IntroductionMessageFragment;
 import org.briarproject.briar.android.keyagreement.ContactExchangeActivity;
 import org.briarproject.briar.android.keyagreement.ContactExchangeErrorFragment;
-import org.briarproject.briar.android.keyagreement.IntroFragment;
 import org.briarproject.briar.android.keyagreement.KeyAgreementActivity;
 import org.briarproject.briar.android.keyagreement.KeyAgreementFragment;
 import org.briarproject.briar.android.login.AuthorNameFragment;
@@ -48,7 +48,6 @@ import org.briarproject.briar.android.privategroup.conversation.GroupActivity;
 import org.briarproject.briar.android.privategroup.conversation.GroupConversationModule;
 import org.briarproject.briar.android.privategroup.creation.CreateGroupActivity;
 import org.briarproject.briar.android.privategroup.creation.CreateGroupFragment;
-import org.briarproject.briar.android.privategroup.creation.CreateGroupMessageFragment;
 import org.briarproject.briar.android.privategroup.creation.CreateGroupModule;
 import org.briarproject.briar.android.privategroup.creation.GroupInviteActivity;
 import org.briarproject.briar.android.privategroup.creation.GroupInviteFragment;
@@ -69,10 +68,8 @@ import org.briarproject.briar.android.sharing.ForumInvitationActivity;
 import org.briarproject.briar.android.sharing.ForumSharingStatusActivity;
 import org.briarproject.briar.android.sharing.ShareBlogActivity;
 import org.briarproject.briar.android.sharing.ShareBlogFragment;
-import org.briarproject.briar.android.sharing.ShareBlogMessageFragment;
 import org.briarproject.briar.android.sharing.ShareForumActivity;
 import org.briarproject.briar.android.sharing.ShareForumFragment;
-import org.briarproject.briar.android.sharing.ShareForumMessageFragment;
 import org.briarproject.briar.android.sharing.SharingModule;
 import org.briarproject.briar.android.splash.SplashScreenActivity;
 import org.briarproject.briar.android.test.TestDataActivity;
@@ -182,8 +179,6 @@ public interface ActivityComponent {
 
 	void inject(CreateGroupFragment fragment);
 
-	void inject(CreateGroupMessageFragment fragment);
-
 	void inject(GroupListFragment fragment);
 
 	void inject(GroupInviteFragment fragment);
@@ -194,20 +189,14 @@ public interface ActivityComponent {
 
 	void inject(FeedFragment fragment);
 
-	void inject(IntroFragment fragment);
-
 	void inject(KeyAgreementFragment fragment);
 
 	void inject(ContactChooserFragment fragment);
 
 	void inject(ShareForumFragment fragment);
 
-	void inject(ShareForumMessageFragment fragment);
-
 	void inject(ShareBlogFragment fragment);
 
-	void inject(ShareBlogMessageFragment fragment);
-
 	void inject(IntroductionMessageFragment fragment);
 
 	void inject(SettingsFragment fragment);
@@ -218,4 +207,6 @@ public interface ActivityComponent {
 
 	void inject(AliasDialogFragment aliasDialogFragment);
 
+	void inject(ImageFragment imageFragment);
+
 }

briar-android/src/main/java/org/briarproject/briar/android/activity/BaseActivity.java

@@ -15,6 +15,8 @@ import android.view.ViewGroup.LayoutParams;
 import android.view.inputmethod.InputMethodManager;
 
 import org.briarproject.bramble.api.db.DbException;
+import org.briarproject.bramble.api.nullsafety.MethodsNotNullByDefault;
+import org.briarproject.bramble.api.nullsafety.ParametersNotNullByDefault;
 import org.briarproject.briar.R;
 import org.briarproject.briar.android.AndroidComponent;
 import org.briarproject.briar.android.BriarApplication;
@@ -51,6 +53,8 @@ import static org.briarproject.briar.android.TestingConstants.PREVENT_SCREENSHOT
  * Warning: Some activities don't extend {@link BaseActivity}.
  *          E.g. {@link DevReportActivity}
  */
+@MethodsNotNullByDefault
+@ParametersNotNullByDefault
 public abstract class BaseActivity extends AppCompatActivity
 		implements DestroyableContext, OnTapFilteredListener {
 
@@ -77,6 +81,17 @@ public abstract class BaseActivity extends AppCompatActivity
 
 	@Override
 	public void onCreate(@Nullable Bundle state) {
+		// create the ActivityComponent *before* calling super.onCreate()
+		// because it already attaches fragments which need access
+		// to the component for their own injection
+		AndroidComponent applicationComponent =
+				((BriarApplication) getApplication()).getApplicationComponent();
+		activityComponent = DaggerActivityComponent.builder()
+				.androidComponent(applicationComponent)
+				.activityModule(getActivityModule())
+				.forumModule(getForumModule())
+				.build();
+		injectActivity(activityComponent);
 		super.onCreate(state);
 
 		// WARNING: When removing this or making it possible to turn it off,
@@ -86,17 +101,6 @@ public abstract class BaseActivity extends AppCompatActivity
 		//          unlock screen is shown.
 		if (PREVENT_SCREENSHOTS) getWindow().addFlags(FLAG_SECURE);
 
-		AndroidComponent applicationComponent =
-				((BriarApplication) getApplication()).getApplicationComponent();
-
-		activityComponent = DaggerActivityComponent.builder()
-				.androidComponent(applicationComponent)
-				.activityModule(getActivityModule())
-				.forumModule(getForumModule())
-				.build();
-
-		injectActivity(activityComponent);
-
 		for (ActivityLifecycleController alc : lifecycleControllers) {
 			alc.onActivityCreate(this);
 		}

briar-android/src/main/java/org/briarproject/briar/android/activity/BriarActivity.java

@@ -1,6 +1,5 @@
 package org.briarproject.briar.android.activity;
 
-import android.annotation.SuppressLint;
 import android.content.Intent;
 import android.support.annotation.RequiresApi;
 import android.support.v7.app.ActionBar;
@@ -10,6 +9,8 @@ import android.transition.Transition;
 import android.view.Window;
 import android.widget.CheckBox;
 
+import org.briarproject.bramble.api.nullsafety.MethodsNotNullByDefault;
+import org.briarproject.bramble.api.nullsafety.ParametersNotNullByDefault;
 import org.briarproject.briar.R;
 import org.briarproject.briar.android.controller.BriarController;
 import org.briarproject.briar.android.controller.DbController;
@@ -36,7 +37,8 @@ import static org.briarproject.briar.android.util.UiUtils.excludeSystemUi;
 import static org.briarproject.briar.android.util.UiUtils.getDozeWhitelistingIntent;
 import static org.briarproject.briar.android.util.UiUtils.isSamsung7;
 
-@SuppressLint("Registered")
+@MethodsNotNullByDefault
+@ParametersNotNullByDefault
 public abstract class BriarActivity extends BaseActivity {
 
 	public static final String GROUP_ID = "briar.GROUP_ID";
@@ -60,7 +62,8 @@ public abstract class BriarActivity extends BaseActivity {
 	}
 
 	@Override
-	protected void onActivityResult(int request, int result, Intent data) {
+	protected void onActivityResult(int request, int result,
+			@Nullable Intent data) {
 		super.onActivityResult(request, result, data);
 		if (request == REQUEST_PASSWORD) {
 			// The result can be RESULT_CANCELED if there's no account
@@ -89,7 +92,7 @@ public abstract class BriarActivity extends BaseActivity {
 		} else if (lockManager.isLocked() && !isFinishing()) {
 			// Also check that the activity isn't finishing already.
 			// This is possible if we finished in onActivityResult().
-			// Lauching another UnlockActivity would cause a loop.
+			// Launching another UnlockActivity would cause a loop.
 			Intent i = new Intent(this, UnlockActivity.class);
 			startActivityForResult(i, REQUEST_UNLOCK);
 		} else if (SDK_INT >= 23) {
@@ -111,6 +114,10 @@ public abstract class BriarActivity extends BaseActivity {
 		lockManager.onActivityStop();
 	}
 
+	protected boolean signedIn() {
+		return briarController.accountSignedIn();
+	}
+
 	/**
 	 * Sets the transition animations.
 	 * @param enterTransition used to move views into initial positions
@@ -178,13 +185,15 @@ public abstract class BriarActivity extends BaseActivity {
 		b.show();
 	}
 
-	protected void signOut(boolean removeFromRecentApps) {
+	protected void signOut(boolean removeFromRecentApps,
+			boolean deleteAccount) {
 		if (briarController.accountSignedIn()) {
 			// Don't use UiResultHandler because we want the result even if
 			// this activity has been destroyed
 			briarController.signOut(result -> runOnUiThread(
-					() -> exit(removeFromRecentApps)));
+					() -> exit(removeFromRecentApps)), deleteAccount);
 		} else {
+			if (deleteAccount) briarController.deleteAccount();
 			exit(removeFromRecentApps);
 		}
 	}

briar-android/src/main/java/org/briarproject/briar/android/activity/RequestCodes.java

@@ -14,5 +14,7 @@ public interface RequestCodes {
 	int REQUEST_BLUETOOTH_DISCOVERABLE = 10;
 	int REQUEST_UNLOCK = 11;
 	int REQUEST_KEYGUARD_UNLOCK = 12;
+	int REQUEST_ATTACH_IMAGE = 13;
+	int REQUEST_SAVE_ATTACHMENT = 14;
 
 }

briar-android/src/main/java/org/briarproject/briar/android/blog/BasePostFragment.java

@@ -24,6 +24,8 @@ import javax.annotation.Nullable;
 import static android.content.Intent.FLAG_ACTIVITY_CLEAR_TOP;
 import static android.view.View.INVISIBLE;
 import static android.view.View.VISIBLE;
+import static java.util.Objects.requireNonNull;
+import static java.util.logging.Logger.getLogger;
 import static org.briarproject.briar.android.activity.BriarActivity.GROUP_ID;
 import static org.briarproject.briar.android.util.UiUtils.MIN_DATE_RESOLUTION;
 
@@ -35,7 +37,7 @@ abstract class BasePostFragment extends BaseFragment {
 	static final String POST_ID = "briar.POST_ID";
 
 	private static final Logger LOG =
-			Logger.getLogger(BasePostFragment.class.getName());
+			getLogger(BasePostFragment.class.getName());
 
 	private final Handler handler = new Handler(Looper.getMainLooper());
 
@@ -52,7 +54,7 @@ abstract class BasePostFragment extends BaseFragment {
 			@Nullable ViewGroup container,
 			@Nullable Bundle savedInstanceState) {
 		// retrieve MessageId of blog post from arguments
-		byte[] p = getArguments().getByteArray(POST_ID);
+		byte[] p = requireNonNull(getArguments()).getByteArray(POST_ID);
 		if (p == null) throw new IllegalStateException("No post ID in args");
 		postId = new MessageId(p);
 
@@ -68,6 +70,7 @@ abstract class BasePostFragment extends BaseFragment {
 
 			@Override
 			public void onAuthorClick(BlogPostItem post) {
+				if (getContext() == null) return;
 				Intent i = new Intent(getContext(), BlogActivity.class);
 				i.putExtra(GROUP_ID, post.getGroupId().getBytes());
 				i.setFlags(FLAG_ACTIVITY_CLEAR_TOP);

briar-android/src/main/java/org/briarproject/briar/android/blog/BlogFragment.java

@@ -3,12 +3,14 @@ package org.briarproject.briar.android.blog;
 import android.content.DialogInterface;
 import android.content.Intent;
 import android.os.Bundle;
+import android.os.Parcelable;
 import android.support.annotation.UiThread;
 import android.support.design.widget.Snackbar;
 import android.support.v4.content.ContextCompat;
 import android.support.v7.app.ActionBar;
 import android.support.v7.app.AlertDialog;
 import android.support.v7.widget.LinearLayoutManager;
+import android.support.v7.widget.RecyclerView.LayoutManager;
 import android.view.LayoutInflater;
 import android.view.Menu;
 import android.view.MenuInflater;
@@ -43,6 +45,7 @@ import javax.inject.Inject;
 import static android.app.Activity.RESULT_OK;
 import static android.content.Intent.FLAG_ACTIVITY_CLEAR_TOP;
 import static android.widget.Toast.LENGTH_SHORT;
+import static java.util.Objects.requireNonNull;
 import static org.briarproject.briar.android.activity.BriarActivity.GROUP_ID;
 import static org.briarproject.briar.android.activity.RequestCodes.REQUEST_SHARE_BLOG;
 import static org.briarproject.briar.android.activity.RequestCodes.REQUEST_WRITE_BLOG_POST;
@@ -61,15 +64,17 @@ public class BlogFragment extends BaseFragment
 	BlogController blogController;
 	@Inject
 	SharingController sharingController;
+	@Nullable
+	private Parcelable layoutManagerState;
 
 	private GroupId groupId;
 	private BlogPostAdapter adapter;
+	private LayoutManager layoutManager;
 	private BriarRecyclerView list;
 	private MenuItem writeButton, deleteButton;
 	private boolean isMyBlog = false, canDeleteBlog = false;
 
 	static BlogFragment newInstance(GroupId groupId) {
-
 		BlogFragment f = new BlogFragment();
 
 		Bundle bundle = new Bundle();
@@ -79,34 +84,40 @@ public class BlogFragment extends BaseFragment
 		return f;
 	}
 
+	@Override
+	public void injectFragment(ActivityComponent component) {
+		component.inject(this);
+		blogController.setBlogSharingListener(this);
+		sharingController.setSharingListener(this);
+	}
+
 	@Nullable
 	@Override
 	public View onCreateView(LayoutInflater inflater,
 			@Nullable ViewGroup container,
 			@Nullable Bundle savedInstanceState) {
-		Bundle args = getArguments();
+		Bundle args = requireNonNull(getArguments());
 		byte[] b = args.getByteArray(GROUP_ID);
 		if (b == null) throw new IllegalStateException("No group ID in args");
 		groupId = new GroupId(b);
 
 		View v = inflater.inflate(R.layout.fragment_blog, container, false);
 
-		adapter =
-				new BlogPostAdapter(getActivity(), this, getFragmentManager());
+		adapter = new BlogPostAdapter(requireNonNull(getActivity()), this,
+				getFragmentManager());
 		list = v.findViewById(R.id.postList);
-		list.setLayoutManager(new LinearLayoutManager(getActivity()));
+		layoutManager = new LinearLayoutManager(getActivity());
+		list.setLayoutManager(layoutManager);
 		list.setAdapter(adapter);
 		list.showProgressBar();
 		list.setEmptyText(getString(R.string.blogs_other_blog_empty_state));
 
-		return v;
-	}
+		if (savedInstanceState != null) {
+			layoutManagerState =
+					savedInstanceState.getParcelable("layoutManager");
+		}
 
-	@Override
-	public void injectFragment(ActivityComponent component) {
-		component.inject(this);
-		blogController.setBlogSharingListener(this);
-		sharingController.setSharingListener(this);
+		return v;
 	}
 
 	@Override
@@ -126,6 +137,15 @@ public class BlogFragment extends BaseFragment
 		list.stopPeriodicUpdate();
 	}
 
+	@Override
+	public void onSaveInstanceState(Bundle outState) {
+		super.onSaveInstanceState(outState);
+		if (layoutManager != null) {
+			layoutManagerState = layoutManager.onSaveInstanceState();
+			outState.putParcelable("layoutManager", layoutManagerState);
+		}
+	}
+
 	@Override
 	public void onCreateOptionsMenu(Menu menu, MenuInflater inflater) {
 		inflater.inflate(R.menu.blogs_blog_actions, menu);
@@ -218,7 +238,10 @@ public class BlogFragment extends BaseFragment
 
 	@Override
 	public void onAuthorClick(BlogPostItem post) {
-		if (post.getGroupId().equals(groupId)) return; // We're already there
+		if (post.getGroupId().equals(groupId) || getContext() == null) {
+			// We're already there
+			return;
+		}
 		Intent i = new Intent(getContext(), BlogActivity.class);
 		i.putExtra(GROUP_ID, post.getGroupId().getBytes());
 		i.setFlags(FLAG_ACTIVITY_CLEAR_TOP);
@@ -235,7 +258,12 @@ public class BlogFragment extends BaseFragment
 							list.showData();
 						} else {
 							adapter.addAll(posts);
-							if (reload) list.scrollToPosition(0);
+							if (reload || layoutManagerState == null) {
+								list.scrollToPosition(0);
+							} else {
+								layoutManager.onRestoreInstanceState(
+										layoutManagerState);
+							}
 						}
 					}
 

briar-android/src/main/java/org/briarproject/briar/android/blog/FeedFragment.java

@@ -2,6 +2,7 @@ package org.briarproject.briar.android.blog;
 
 import android.content.Intent;
 import android.os.Bundle;
+import android.os.Parcelable;
 import android.support.annotation.UiThread;
 import android.support.design.widget.Snackbar;
 import android.support.v4.content.ContextCompat;
@@ -35,6 +36,7 @@ import javax.inject.Inject;
 import static android.app.Activity.RESULT_OK;
 import static android.content.Intent.FLAG_ACTIVITY_CLEAR_TOP;
 import static android.support.design.widget.Snackbar.LENGTH_LONG;
+import static java.util.Objects.requireNonNull;
 import static org.briarproject.briar.android.activity.BriarActivity.GROUP_ID;
 import static org.briarproject.briar.android.activity.RequestCodes.REQUEST_WRITE_BLOG_POST;
 
@@ -53,7 +55,10 @@ public class FeedFragment extends BaseFragment implements
 	private BlogPostAdapter adapter;
 	private LinearLayoutManager layoutManager;
 	private BriarRecyclerView list;
-	private Blog personalBlog = null;
+	@Nullable
+	private Blog personalBlog;
+	@Nullable
+	private Parcelable layoutManagerState;
 
 	public static FeedFragment newInstance() {
 		FeedFragment f = new FeedFragment();
@@ -64,13 +69,18 @@ public class FeedFragment extends BaseFragment implements
 		return f;
 	}
 
+	@Override
+	public void injectFragment(ActivityComponent component) {
+		component.inject(this);
+		feedController.setFeedListener(this);
+	}
+
 	@Nullable
 	@Override
 	public View onCreateView(LayoutInflater inflater,
 			@Nullable ViewGroup container,
 			@Nullable Bundle savedInstanceState) {
-
-		getActivity().setTitle(R.string.blogs_button);
+		requireNonNull(getActivity()).setTitle(R.string.blogs_button);
 
 		View v = inflater.inflate(R.layout.fragment_blog, container, false);
 
@@ -85,13 +95,12 @@ public class FeedFragment extends BaseFragment implements
 		list.setEmptyText(R.string.blogs_feed_empty_state);
 		list.setEmptyAction(R.string.blogs_feed_empty_state_action);
 
-		return v;
-	}
+		if (savedInstanceState != null) {
+			layoutManagerState =
+					savedInstanceState.getParcelable("layoutManager");
+		}
 
-	@Override
-	public void injectFragment(ActivityComponent component) {
-		component.inject(this);
-		feedController.setFeedListener(this);
+		return v;
 	}
 
 	@Override
@@ -123,6 +132,15 @@ public class FeedFragment extends BaseFragment implements
 		// TODO save list position in database/preferences?
 	}
 
+	@Override
+	public void onSaveInstanceState(Bundle outState) {
+		super.onSaveInstanceState(outState);
+		if (layoutManager != null) {
+			layoutManagerState = layoutManager.onSaveInstanceState();
+			outState.putParcelable("layoutManager", layoutManagerState);
+		}
+	}
+
 	private void loadPersonalBlog() {
 		feedController.loadPersonalBlog(
 				new UiResultExceptionHandler<Blog, DbException>(this) {
@@ -150,6 +168,12 @@ public class FeedFragment extends BaseFragment implements
 							if (clear) adapter.setItems(posts);
 							else adapter.addAll(posts);
 							if (posts.isEmpty()) list.showData();
+							if (layoutManagerState == null) {
+								list.scrollToPosition(0);  // Scroll to the top
+							} else {
+								layoutManager.onRestoreInstanceState(
+										layoutManagerState);
+							}
 						} else {
 							LOG.info("Concurrent update, reloading");
 							loadBlogPosts(clear);

briar-android/src/main/java/org/briarproject/briar/android/blog/FeedPostFragment.java

@@ -17,6 +17,7 @@ import org.briarproject.briar.android.controller.handler.UiResultExceptionHandle
 import javax.annotation.Nullable;
 import javax.inject.Inject;
 
+import static java.util.Objects.requireNonNull;
 import static org.briarproject.briar.android.activity.BriarActivity.GROUP_ID;
 
 @UiThread
@@ -42,13 +43,17 @@ public class FeedPostFragment extends BasePostFragment {
 		return f;
 	}
 
+	@Override
+	public void injectFragment(ActivityComponent component) {
+		component.inject(this);
+	}
+
 	@Nullable
 	@Override
 	public View onCreateView(LayoutInflater inflater,
 			@Nullable ViewGroup container,
 			@Nullable Bundle savedInstanceState) {
-
-		Bundle args = getArguments();
+		Bundle args = requireNonNull(getArguments());
 		byte[] b = args.getByteArray(GROUP_ID);
 		if (b == null) throw new IllegalStateException("No group ID in args");
 		blogId = new GroupId(b);
@@ -61,11 +66,6 @@ public class FeedPostFragment extends BasePostFragment {
 		return TAG;
 	}
 
-	@Override
-	public void injectFragment(ActivityComponent component) {
-		component.inject(this);
-	}
-
 	@Override
 	public void onStart() {
 		super.onStart();

briar-android/src/main/java/org/briarproject/briar/android/blog/ReblogFragment.java

@@ -1,5 +1,6 @@
 package org.briarproject.briar.android.blog;
 
+import android.net.Uri;
 import android.os.Bundle;
 import android.view.LayoutInflater;
 import android.view.View;
@@ -18,7 +19,10 @@ import org.briarproject.briar.android.controller.handler.UiExceptionHandler;
 import org.briarproject.briar.android.controller.handler.UiResultExceptionHandler;
 import org.briarproject.briar.android.fragment.BaseFragment;
 import org.briarproject.briar.android.view.TextInputView;
-import org.briarproject.briar.android.view.TextInputView.TextInputListener;
+import org.briarproject.briar.android.view.TextSendController;
+import org.briarproject.briar.android.view.TextSendController.SendListener;
+
+import java.util.List;
 
 import javax.annotation.Nullable;
 import javax.inject.Inject;
@@ -27,18 +31,18 @@ import static android.view.View.FOCUS_DOWN;
 import static android.view.View.GONE;
 import static android.view.View.INVISIBLE;
 import static android.view.View.VISIBLE;
+import static java.util.Objects.requireNonNull;
 import static org.briarproject.briar.android.activity.BriarActivity.GROUP_ID;
 import static org.briarproject.briar.android.blog.BasePostFragment.POST_ID;
+import static org.briarproject.briar.api.blog.BlogConstants.MAX_BLOG_POST_TEXT_LENGTH;
 
 @MethodsNotNullByDefault
 @ParametersNotNullByDefault
-public class ReblogFragment extends BaseFragment implements TextInputListener {
+public class ReblogFragment extends BaseFragment implements SendListener {
 
 	public static final String TAG = ReblogFragment.class.getName();
 
 	private ViewHolder ui;
-	private GroupId blogId;
-	private MessageId postId;
 	private BlogPostItem item;
 
 	@Inject
@@ -70,24 +74,22 @@ public class ReblogFragment extends BaseFragment implements TextInputListener {
 			@Nullable ViewGroup container,
 			@Nullable Bundle savedInstanceState) {
 
-		Bundle args = getArguments();
-		blogId = new GroupId(args.getByteArray(GROUP_ID));
-		postId = new MessageId(args.getByteArray(POST_ID));
+		Bundle args = requireNonNull(getArguments());
+		GroupId blogId =
+				new GroupId(requireNonNull(args.getByteArray(GROUP_ID)));
+		MessageId postId =
+				new MessageId(requireNonNull(args.getByteArray(POST_ID)));
 
 		View v = inflater.inflate(R.layout.fragment_reblog, container, false);
 		ui = new ViewHolder(v);
 		ui.post.setTransitionName(postId);
-		ui.input.setSendButtonEnabled(false);
+		TextSendController sendController =
+				new TextSendController(ui.input, this, true);
+		ui.input.setSendController(sendController);
+		ui.input.setEnabled(false);
+		ui.input.setMaxTextLength(MAX_BLOG_POST_TEXT_LENGTH);
 		showProgressBar();
 
-		return v;
-	}
-
-	@Override
-	public void onStart() {
-		super.onStart();
-
-		// TODO: Load blog post when fragment is created. #631
 		feedController.loadBlogPost(blogId, postId,
 				new UiResultExceptionHandler<BlogPostItem, DbException>(
 						this) {
@@ -102,6 +104,8 @@ public class ReblogFragment extends BaseFragment implements TextInputListener {
 						handleDbException(exception);
 					}
 				});
+
+		return v;
 	}
 
 	private void bindViewHolder() {
@@ -112,16 +116,14 @@ public class ReblogFragment extends BaseFragment implements TextInputListener {
 		ui.post.bindItem(item);
 		ui.post.hideReblogButton();
 
-		ui.input.setListener(this);
-		ui.input.setSendButtonEnabled(true);
+		ui.input.setEnabled(true);
 		ui.scrollView.post(() -> ui.scrollView.fullScroll(FOCUS_DOWN));
 	}
 
 	@Override
-	public void onSendClick(String text) {
+	public void onSendClick(@Nullable String text, List<Uri> imageUris) {
 		ui.input.hideSoftKeyboard();
-		String comment = getComment();
-		feedController.repeatPost(item, comment,
+		feedController.repeatPost(item, text,
 				new UiExceptionHandler<DbException>(this) {
 					@Override
 					public void onExceptionUi(DbException exception) {
@@ -131,12 +133,6 @@ public class ReblogFragment extends BaseFragment implements TextInputListener {
 		finish();
 	}
 
-	@Nullable
-	private String getComment() {
-		if (ui.input.getText().length() == 0) return null;
-		return ui.input.getText().toString();
-	}
-
 	private void showProgressBar() {
 		ui.progressBar.setVisibility(VISIBLE);
 		ui.input.setVisibility(GONE);

briar-android/src/main/java/org/briarproject/briar/android/blog/RssFeedImportActivity.java

@@ -29,6 +29,7 @@ import javax.inject.Inject;
 
 import static android.view.View.GONE;
 import static android.view.View.VISIBLE;
+import static android.view.inputmethod.EditorInfo.IME_ACTION_DONE;
 import static java.util.logging.Level.WARNING;
 import static org.briarproject.bramble.util.LogUtils.logException;
 
@@ -72,6 +73,15 @@ public class RssFeedImportActivity extends BriarActivity {
 				enableOrDisableImportButton();
 			}
 		});
+		urlInput.setOnEditorActionListener((v, actionId, event) -> {
+			if (actionId == IME_ACTION_DONE && importButton.isEnabled() &&
+					importButton.getVisibility() == VISIBLE) {
+				publish();
+				hideSoftKeyboard(urlInput);
+				return true;
+			}
+			return false;
+		});
 
 		importButton = findViewById(R.id.importButton);
 		importButton.setOnClickListener(v -> publish());

briar-android/src/main/java/org/briarproject/briar/android/blog/WriteBlogPostActivity.java

@@ -1,9 +1,9 @@
 package org.briarproject.briar.android.blog;
 
 import android.content.Intent;
+import android.net.Uri;
 import android.os.Bundle;
-import android.text.Editable;
-import android.text.TextWatcher;
+import android.support.annotation.Nullable;
 import android.view.KeyEvent;
 import android.view.MenuItem;
 import android.widget.ProgressBar;
@@ -14,19 +14,22 @@ import org.briarproject.bramble.api.FormatException;
 import org.briarproject.bramble.api.db.DbException;
 import org.briarproject.bramble.api.identity.IdentityManager;
 import org.briarproject.bramble.api.identity.LocalAuthor;
+import org.briarproject.bramble.api.nullsafety.MethodsNotNullByDefault;
+import org.briarproject.bramble.api.nullsafety.ParametersNotNullByDefault;
 import org.briarproject.bramble.api.sync.GroupId;
-import org.briarproject.bramble.util.StringUtils;
 import org.briarproject.briar.R;
 import org.briarproject.briar.android.activity.ActivityComponent;
 import org.briarproject.briar.android.activity.BriarActivity;
 import org.briarproject.briar.android.view.TextInputView;
-import org.briarproject.briar.android.view.TextInputView.TextInputListener;
+import org.briarproject.briar.android.view.TextSendController;
+import org.briarproject.briar.android.view.TextSendController.SendListener;
 import org.briarproject.briar.api.android.AndroidNotificationManager;
 import org.briarproject.briar.api.blog.BlogManager;
 import org.briarproject.briar.api.blog.BlogPost;
 import org.briarproject.briar.api.blog.BlogPostFactory;
 
 import java.security.GeneralSecurityException;
+import java.util.List;
 import java.util.logging.Logger;
 
 import javax.inject.Inject;
@@ -35,10 +38,13 @@ import static android.view.View.GONE;
 import static android.view.View.VISIBLE;
 import static java.util.logging.Level.WARNING;
 import static org.briarproject.bramble.util.LogUtils.logException;
+import static org.briarproject.bramble.util.StringUtils.isNullOrEmpty;
 import static org.briarproject.briar.api.blog.BlogConstants.MAX_BLOG_POST_TEXT_LENGTH;
 
+@MethodsNotNullByDefault
+@ParametersNotNullByDefault
 public class WriteBlogPostActivity extends BriarActivity
-		implements OnEditorActionListener, TextInputListener {
+		implements OnEditorActionListener, SendListener {
 
 	private static final Logger LOG =
 			Logger.getLogger(WriteBlogPostActivity.class.getName());
@@ -58,9 +64,8 @@ public class WriteBlogPostActivity extends BriarActivity
 	@Inject
 	volatile BlogManager blogManager;
 
-	@SuppressWarnings("ConstantConditions")
 	@Override
-	public void onCreate(Bundle state) {
+	public void onCreate(@Nullable Bundle state) {
 		super.onCreate(state);
 
 		Intent i = getIntent();
@@ -71,24 +76,10 @@ public class WriteBlogPostActivity extends BriarActivity
 		setContentView(R.layout.activity_write_blog_post);
 
 		input = findViewById(R.id.textInput);
-		input.setSendButtonEnabled(false);
-		input.addTextChangedListener(new TextWatcher() {
-			@Override
-			public void beforeTextChanged(CharSequence s, int start, int count,
-					int after) {
-			}
-
-			@Override
-			public void onTextChanged(CharSequence s, int start, int before,
-					int count) {
-			}
-
-			@Override
-			public void afterTextChanged(Editable s) {
-				enableOrDisablePublishButton();
-			}
-		});
-		input.setListener(this);
+		TextSendController sendController =
+				new TextSendController(input, this, false);
+		input.setSendController(sendController);
+		input.setMaxTextLength(MAX_BLOG_POST_TEXT_LENGTH);
 
 		progressBar = findViewById(R.id.progressBar);
 	}
@@ -127,18 +118,15 @@ public class WriteBlogPostActivity extends BriarActivity
 		return true;
 	}
 
-	private void enableOrDisablePublishButton() {
-		input.setSendButtonEnabled(input.getText().length() > 0);
-	}
-
 	@Override
-	public void onSendClick(String text) {
+	public void onSendClick(@Nullable String text, List<Uri> imageUris) {
+		if (isNullOrEmpty(text)) throw new AssertionError();
+
 		// hide publish button, show progress bar
 		input.hideSoftKeyboard();
 		input.setVisibility(GONE);
 		progressBar.setVisibility(VISIBLE);
 
-		text = StringUtils.truncateUtf8(text, MAX_BLOG_POST_TEXT_LENGTH);
 		storePost(text);
 	}
 

briar-android/src/main/java/org/briarproject/briar/android/contact/BaseContactListAdapter.java

@@ -38,7 +38,7 @@ public abstract class BaseContactListAdapter<I extends ContactItem, VH extends C
 
 	@Override
 	public boolean areItemsTheSame(I c1, I c2) {
-		return c1.getContact().getId().equals(c2.getContact().getId());
+		return c1.getContact().equals(c2.getContact());
 	}
 
 	@Override
@@ -47,8 +47,7 @@ public abstract class BaseContactListAdapter<I extends ContactItem, VH extends C
 	}
 
 	int findItemPosition(ContactId c) {
-		int count = getItemCount();
-		for (int i = 0; i < count; i++) {
+		for (int i = 0; i < getItemCount(); i++) {
 			I item = getItemAt(i);
 			if (item != null && item.getContact().getId().equals(c))
 				return i;

briar-android/src/main/java/org/briarproject/briar/android/contact/ContactListAdapter.java

@@ -5,8 +5,10 @@ import android.view.LayoutInflater;
 import android.view.View;
 import android.view.ViewGroup;
 
+import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
 import org.briarproject.briar.R;
 
+@NotNullByDefault
 public class ContactListAdapter extends
 		BaseContactListAdapter<ContactListItem, ContactListItemViewHolder> {
 
@@ -28,6 +30,9 @@ public class ContactListAdapter extends
 	public boolean areContentsTheSame(ContactListItem c1, ContactListItem c2) {
 		// check for all properties that influence visual
 		// representation of contact
+		if (c1.isEmpty() != c2.isEmpty()) {
+			return false;
+		}
 		if (c1.getUnreadCount() != c2.getUnreadCount()) {
 			return false;
 		}
@@ -39,11 +44,7 @@ public class ContactListAdapter extends
 
 	@Override
 	public int compare(ContactListItem c1, ContactListItem c2) {
-		long time1 = c1.getTimestamp();
-		long time2 = c2.getTimestamp();
-		if (time1 < time2) return 1;
-		if (time1 > time2) return -1;
-		return 0;
+		return Long.compare(c2.getTimestamp(), c1.getTimestamp());
 	}
 
 }

briar-android/src/main/java/org/briarproject/briar/android/contact/ContactListFragment.java

@@ -51,11 +51,13 @@ import javax.inject.Inject;
 import static android.os.Build.VERSION.SDK_INT;
 import static android.support.v4.app.ActivityOptionsCompat.makeSceneTransitionAnimation;
 import static android.support.v4.view.ViewCompat.getTransitionName;
+import static java.util.Objects.requireNonNull;
 import static java.util.logging.Level.WARNING;
 import static org.briarproject.bramble.util.LogUtils.logDuration;
 import static org.briarproject.bramble.util.LogUtils.logException;
 import static org.briarproject.bramble.util.LogUtils.now;
 import static org.briarproject.briar.android.conversation.ConversationActivity.CONTACT_ID;
+import static org.briarproject.briar.android.util.UiUtils.isSamsung7;
 
 @MethodsNotNullByDefault
 @ParametersNotNullByDefault
@@ -102,8 +104,7 @@ public class ContactListFragment extends BaseFragment implements EventListener {
 	public View onCreateView(LayoutInflater inflater,
 			@Nullable ViewGroup container,
 			@Nullable Bundle savedInstanceState) {
-
-		getActivity().setTitle(R.string.contact_list_button);
+		requireNonNull(getActivity()).setTitle(R.string.contact_list_button);
 
 		View contentView = inflater.inflate(R.layout.list, container, false);
 
@@ -114,7 +115,7 @@ public class ContactListFragment extends BaseFragment implements EventListener {
 					ContactId contactId = item.getContact().getId();
 					i.putExtra(CONTACT_ID, contactId.getInt());
 
-					if (SDK_INT >= 23) {
+					if (SDK_INT >= 23 && !isSamsung7()) {
 						ContactListItemViewHolder holder =
 								(ContactListItemViewHolder) list
 										.getRecyclerView()
@@ -280,7 +281,7 @@ public class ContactListFragment extends BaseFragment implements EventListener {
 			ContactListItem item = adapter.getItemAt(position);
 			if (item != null) {
 				item.setConnected(connected);
-				adapter.notifyItemChanged(position);
+				adapter.updateItemAt(position, item);
 			}
 		});
 	}

briar-android/src/main/java/org/briarproject/briar/android/contactselection/BaseContactSelectorFragment.java

@@ -25,6 +25,7 @@ import java.util.Collection;
 
 import javax.annotation.Nullable;
 
+import static java.util.Objects.requireNonNull;
 import static org.briarproject.briar.android.activity.BriarActivity.GROUP_ID;
 import static org.briarproject.briar.android.contactselection.ContactSelectorActivity.CONTACTS;
 import static org.briarproject.briar.android.contactselection.ContactSelectorActivity.getContactsFromIds;
@@ -50,10 +51,10 @@ public abstract class BaseContactSelectorFragment<I extends SelectableContactIte
 	}
 
 	@Override
-	public void onCreate(Bundle savedInstanceState) {
+	public void onCreate(@Nullable Bundle savedInstanceState) {
 		super.onCreate(savedInstanceState);
 
-		Bundle args = getArguments();
+		Bundle args = requireNonNull(getArguments());
 		byte[] b = args.getByteArray(GROUP_ID);
 		if (b == null) throw new IllegalStateException("No GroupId");
 		groupId = new GroupId(b);
@@ -72,7 +73,7 @@ public abstract class BaseContactSelectorFragment<I extends SelectableContactIte
 		list.setEmptyImage(R.drawable.ic_empty_state_contact_list);
 		list.setEmptyText(getString(R.string.no_contacts_selector));
 		list.setEmptyAction(getString(R.string.no_contacts_selector_action));
-		adapter = getAdapter(getContext(), this);
+		adapter = getAdapter(requireNonNull(getContext()), this);
 		list.setAdapter(adapter);
 
 		// restore selected contacts if available

briar-android/src/main/java/org/briarproject/briar/android/controller/BriarController.java

@@ -16,5 +16,8 @@ public interface BriarController extends ActivityLifecycleController {
 
 	void doNotAskAgainForDozeWhiteListing();
 
-	void signOut(ResultHandler<Void> eventHandler);
+	void signOut(ResultHandler<Void> eventHandler, boolean deleteAccount);
+
+	void deleteAccount();
+
 }

briar-android/src/main/java/org/briarproject/briar/android/controller/BriarControllerImpl.java

@@ -120,7 +120,8 @@ public class BriarControllerImpl implements BriarController {
 	}
 
 	@Override
-	public void signOut(ResultHandler<Void> eventHandler) {
+	public void signOut(ResultHandler<Void> eventHandler,
+			boolean deleteAccount) {
 		new Thread(() -> {
 			try {
 				// Wait for the service to finish starting up
@@ -134,11 +135,18 @@ public class BriarControllerImpl implements BriarController {
 				service.waitForShutdown();
 			} catch (InterruptedException e) {
 				LOG.warning("Interrupted while waiting for service");
+			} finally {
+				if (deleteAccount) accountManager.deleteAccount();
 			}
 			eventHandler.onResult(null);
 		}).start();
 	}
 
+	@Override
+	public void deleteAccount() {
+		accountManager.deleteAccount();
+	}
+
 	private void unbindService() {
 		if (bound) activity.unbindService(serviceConnection);
 	}

briar-android/src/main/java/org/briarproject/briar/android/conversation/AliasDialogFragment.java

@@ -39,8 +39,8 @@ public class AliasDialogFragment extends AppCompatDialogFragment {
 
 		setStyle(STYLE_NO_TITLE, R.style.BriarDialogTheme);
 
-		if (getActivity() == null) return;
-		((BriarActivity) getActivity()).getActivityComponent().inject(this);
+		BriarActivity a = (BriarActivity) requireNonNull(getActivity());
+		a.getActivityComponent().inject(this);
 		viewModel = ViewModelProviders.of(getActivity(), viewModelFactory)
 				.get(ConversationViewModel.class);
 	}
@@ -48,7 +48,6 @@ public class AliasDialogFragment extends AppCompatDialogFragment {
 	@Override
 	public View onCreateView(@NonNull LayoutInflater inflater,
 			ViewGroup container, Bundle savedInstanceState) {
-
 		View v = inflater.inflate(R.layout.fragment_alias_dialog, container,
 				false);
 
@@ -69,4 +68,5 @@ public class AliasDialogFragment extends AppCompatDialogFragment {
 
 		return v;
 	}
+
 }

briar-android/src/main/java/org/briarproject/briar/android/conversation/AttachmentController.java

@@ -1,20 +1,24 @@
 package org.briarproject.briar.android.conversation;
 
-import android.content.res.Resources;
 import android.graphics.BitmapFactory;
+import android.graphics.BitmapFactory.Options;
 import android.support.annotation.Nullable;
 import android.support.media.ExifInterface;
+import android.webkit.MimeTypeMap;
+
+import com.bumptech.glide.util.MarkEnforcingInputStream;
 
 import org.briarproject.bramble.api.Pair;
 import org.briarproject.bramble.api.db.DatabaseExecutor;
 import org.briarproject.bramble.api.db.DbException;
 import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
 import org.briarproject.bramble.api.sync.MessageId;
-import org.briarproject.briar.R;
+import org.briarproject.briar.android.conversation.ImageHelper.DecodeResult;
 import org.briarproject.briar.api.messaging.Attachment;
 import org.briarproject.briar.api.messaging.AttachmentHeader;
 import org.briarproject.briar.api.messaging.MessagingManager;
 
+import java.io.BufferedInputStream;
 import java.io.IOException;
 import java.io.InputStream;
 import java.util.ArrayList;
@@ -42,8 +46,10 @@ class AttachmentController {
 
 	private static final Logger LOG =
 			getLogger(AttachmentController.class.getName());
+	private static final int READ_LIMIT = 1024 * 8192;
 
 	private final MessagingManager messagingManager;
+	private final ImageHelper imageHelper;
 	private final int defaultSize;
 	private final int minWidth, maxWidth;
 	private final int minHeight, maxHeight;
@@ -51,18 +57,38 @@ class AttachmentController {
 	private final Map<MessageId, List<AttachmentItem>> attachmentCache =
 			new ConcurrentHashMap<>();
 
-	AttachmentController(MessagingManager messagingManager, Resources res) {
+	AttachmentController(MessagingManager messagingManager,
+			AttachmentDimensions dimensions, ImageHelper imageHelper) {
 		this.messagingManager = messagingManager;
-		defaultSize =
-				res.getDimensionPixelSize(R.dimen.message_bubble_image_default);
-		minWidth = res.getDimensionPixelSize(
-				R.dimen.message_bubble_image_min_width);
-		maxWidth = res.getDimensionPixelSize(
-				R.dimen.message_bubble_image_max_width);
-		minHeight = res.getDimensionPixelSize(
-				R.dimen.message_bubble_image_min_height);
-		maxHeight = res.getDimensionPixelSize(
-				R.dimen.message_bubble_image_max_height);
+		this.imageHelper = imageHelper;
+		defaultSize = dimensions.defaultSize;
+		minWidth = dimensions.minWidth;
+		maxWidth = dimensions.maxWidth;
+		minHeight = dimensions.minHeight;
+		maxHeight = dimensions.maxHeight;
+	}
+
+	AttachmentController(MessagingManager messagingManager,
+			AttachmentDimensions dimensions) {
+		this(messagingManager, dimensions, new ImageHelper() {
+			@Override
+			public DecodeResult decodeStream(InputStream is) {
+				Options options = new Options();
+				options.inJustDecodeBounds = true;
+				BitmapFactory.decodeStream(is, null, options);
+				String mimeType = options.outMimeType;
+				if (mimeType == null) mimeType = "";
+				return new DecodeResult(options.outWidth, options.outHeight,
+						mimeType);
+			}
+
+			@Nullable
+			@Override
+			public String getExtensionFromMimeType(String mimeType) {
+				MimeTypeMap mimeTypeMap = MimeTypeMap.getSingleton();
+				return mimeTypeMap.getExtensionFromMimeType(mimeType);
+			}
+		});
 	}
 
 	void put(MessageId messageId, List<AttachmentItem> attachments) {
@@ -81,31 +107,53 @@ class AttachmentController {
 		List<Pair<AttachmentHeader, Attachment>> attachments =
 				new ArrayList<>(headers.size());
 		for (AttachmentHeader h : headers) {
-			Attachment a =
-					messagingManager.getAttachment(h.getMessageId());
+			Attachment a = messagingManager.getAttachment(h.getMessageId());
 			attachments.add(new Pair<>(h, a));
 		}
 		logDuration(LOG, "Loading attachment", start);
 		return attachments;
 	}
 
+	/**
+	 * Creates {@link AttachmentItem}s from the passed headers and Attachments.
+	 * <p>
+	 * Note: This closes the {@link Attachment}'s {@link InputStream}.
+	 */
 	List<AttachmentItem> getAttachmentItems(
 			List<Pair<AttachmentHeader, Attachment>> attachments) {
+		boolean needsSize = attachments.size() == 1;
 		List<AttachmentItem> items = new ArrayList<>(attachments.size());
 		for (Pair<AttachmentHeader, Attachment> a : attachments) {
 			AttachmentItem item =
-					getAttachmentItem(a.getFirst(), a.getSecond());
+					getAttachmentItem(a.getFirst(), a.getSecond(), needsSize);
 			items.add(item);
 		}
 		return items;
 	}
 
-	private AttachmentItem getAttachmentItem(AttachmentHeader h, Attachment a) {
+	/**
+	 * Creates an {@link AttachmentItem} from the {@link Attachment}'s
+	 * {@link InputStream} which will be closed when this method returns.
+	 */
+	AttachmentItem getAttachmentItem(AttachmentHeader h, Attachment a,
+			boolean needsSize) {
 		MessageId messageId = h.getMessageId();
-		Size size = new Size();
+		if (!needsSize) {
+			String mimeType = h.getContentType();
+			String extension = imageHelper.getExtensionFromMimeType(mimeType);
+			boolean hasError = false;
+			if (extension == null) {
+				extension = "";
+				hasError = true;
+			}
+			return new AttachmentItem(messageId, 0, 0, mimeType, extension, 0,
+					0, hasError);
+		}
 
-		InputStream is = a.getStream();
-		is.mark(Integer.MAX_VALUE);
+		Size size = new Size();
+		InputStream is = new MarkEnforcingInputStream(
+				new BufferedInputStream(a.getStream()));
+		is.mark(READ_LIMIT);
 		try {
 			// use exif to get size
 			if (h.getContentType().equals("image/jpeg")) {
@@ -118,6 +166,8 @@ class AttachmentController {
 			// use BitmapFactory to get size
 			if (size.error) {
 				is.reset();
+				// need to mark again to re-add read limit
+				is.mark(READ_LIMIT);
 				size = getSizeFromBitmap(is);
 			}
 		} catch (IOException e) {
@@ -127,19 +177,24 @@ class AttachmentController {
 		}
 
 		// calculate thumbnail size
-		Size thumbnailSize = new Size(defaultSize, defaultSize);
+		Size thumbnailSize = new Size(defaultSize, defaultSize, size.mimeType);
 		if (!size.error) {
-			thumbnailSize = getThumbnailSize(size.width, size.height);
+			thumbnailSize =
+					getThumbnailSize(size.width, size.height, size.mimeType);
 		}
+		// get file extension
+		String extension = imageHelper.getExtensionFromMimeType(size.mimeType);
+		boolean hasError = extension == null || size.error;
+		if (extension == null) extension = "";
 		return new AttachmentItem(messageId, size.width, size.height,
-				thumbnailSize.width, thumbnailSize.height, size.error);
+				size.mimeType, extension, thumbnailSize.width,
+				thumbnailSize.height, hasError);
 	}
 
 	/**
 	 * Gets the size of a JPEG {@link InputStream} if EXIF info is available.
 	 */
-	private static Size getSizeFromExif(InputStream is)
-			throws IOException {
+	private Size getSizeFromExif(InputStream is) throws IOException {
 		ExifInterface exif = new ExifInterface(is);
 		// these can return 0 independent of default value
 		int width = exif.getAttributeInt(TAG_IMAGE_WIDTH, 0);
@@ -151,24 +206,21 @@ class AttachmentController {
 				orientation == ORIENTATION_TRANSVERSE ||
 				orientation == ORIENTATION_TRANSPOSE) {
 			//noinspection SuspiciousNameCombination
-			return new Size(height, width);
+			return new Size(height, width, "image/jpeg");
 		}
-		return new Size(width, height);
+		return new Size(width, height, "image/jpeg");
 	}
 
 	/**
 	 * Gets the size of any image {@link InputStream}.
 	 */
-	private static Size getSizeFromBitmap(InputStream is) {
-		BitmapFactory.Options options = new BitmapFactory.Options();
-		options.inJustDecodeBounds = true;
-		BitmapFactory.decodeStream(is, null, options);
-		if (options.outWidth < 1 || options.outHeight < 1)
-			return new Size();
-		return new Size(options.outWidth, options.outHeight);
+	private Size getSizeFromBitmap(InputStream is) {
+		DecodeResult result = imageHelper.decodeStream(is);
+		if (result.width < 1 || result.height < 1) return new Size();
+		return new Size(result.width, result.height, result.mimeType);
 	}
 
-	private Size getThumbnailSize(int width, int height) {
+	private Size getThumbnailSize(int width, int height, String mimeType) {
 		float widthPercentage = maxWidth / (float) width;
 		float heightPercentage = maxHeight / (float) height;
 		float scaleFactor = Math.min(widthPercentage, heightPercentage);
@@ -184,24 +236,27 @@ class AttachmentController {
 			if (thumbnailWidth > maxWidth) thumbnailWidth = maxWidth;
 			if (thumbnailHeight > maxHeight) thumbnailHeight = maxHeight;
 		}
-		return new Size(thumbnailWidth, thumbnailHeight);
+		return new Size(thumbnailWidth, thumbnailHeight, mimeType);
 	}
 
 	private static class Size {
 
 		private final int width;
 		private final int height;
+		private final String mimeType;
 		private final boolean error;
 
-		private Size(int width, int height) {
+		private Size(int width, int height, String mimeType) {
 			this.width = width;
 			this.height = height;
+			this.mimeType = mimeType;
 			this.error = false;
 		}
 
 		private Size() {
 			this.width = 0;
 			this.height = 0;
+			this.mimeType = "";
 			this.error = true;
 		}
 	}

briar-android/src/main/java/org/briarproject/briar/android/conversation/AttachmentDimensions.java

@@ -0,0 +1,39 @@
+package org.briarproject.briar.android.conversation;
+
+import android.content.res.Resources;
+import android.support.annotation.VisibleForTesting;
+
+import org.briarproject.briar.R;
+
+class AttachmentDimensions {
+
+	final int defaultSize;
+	final int minWidth, maxWidth;
+	final int minHeight, maxHeight;
+
+	@VisibleForTesting
+	AttachmentDimensions(int defaultSize, int minWidth, int maxWidth,
+			int minHeight, int maxHeight) {
+		this.defaultSize = defaultSize;
+		this.minWidth = minWidth;
+		this.maxWidth = maxWidth;
+		this.minHeight = minHeight;
+		this.maxHeight = maxHeight;
+	}
+
+	static AttachmentDimensions getAttachmentDimensions(Resources res) {
+		int defaultSize =
+				res.getDimensionPixelSize(R.dimen.message_bubble_image_default);
+		int minWidth = res.getDimensionPixelSize(
+				R.dimen.message_bubble_image_min_width);
+		int maxWidth = res.getDimensionPixelSize(
+				R.dimen.message_bubble_image_max_width);
+		int minHeight = res.getDimensionPixelSize(
+				R.dimen.message_bubble_image_min_height);
+		int maxHeight = res.getDimensionPixelSize(
+				R.dimen.message_bubble_image_max_height);
+		return new AttachmentDimensions(defaultSize, minWidth, maxWidth,
+				minHeight, minHeight);
+	}
+
+}

briar-android/src/main/java/org/briarproject/briar/android/conversation/AttachmentItem.java

@@ -2,10 +2,13 @@ package org.briarproject.briar.android.conversation;
 
 import android.os.Parcel;
 import android.os.Parcelable;
+import android.support.annotation.Nullable;
 
 import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
 import org.briarproject.bramble.api.sync.MessageId;
 
+import java.util.concurrent.atomic.AtomicLong;
+
 import javax.annotation.concurrent.Immutable;
 
 @Immutable
@@ -14,8 +17,10 @@ public class AttachmentItem implements Parcelable {
 
 	private final MessageId messageId;
 	private final int width, height;
+	private final String mimeType, extension;
 	private final int thumbnailWidth, thumbnailHeight;
 	private final boolean hasError;
+	private final long instanceId;
 
 	public static final Creator<AttachmentItem> CREATOR =
 			new Creator<AttachmentItem>() {
@@ -30,14 +35,20 @@ public class AttachmentItem implements Parcelable {
 				}
 			};
 
-	AttachmentItem(MessageId messageId, int width, int height,
-			int thumbnailWidth, int thumbnailHeight, boolean hasError) {
+	private static final AtomicLong NEXT_INSTANCE_ID = new AtomicLong(0);
+
+	AttachmentItem(MessageId messageId, int width, int height, String mimeType,
+			String extension, int thumbnailWidth, int thumbnailHeight,
+			boolean hasError) {
 		this.messageId = messageId;
 		this.width = width;
 		this.height = height;
+		this.mimeType = mimeType;
+		this.extension = extension;
 		this.thumbnailWidth = thumbnailWidth;
 		this.thumbnailHeight = thumbnailHeight;
 		this.hasError = hasError;
+		instanceId = NEXT_INSTANCE_ID.getAndIncrement();
 	}
 
 	protected AttachmentItem(Parcel in) {
@@ -46,9 +57,12 @@ public class AttachmentItem implements Parcelable {
 		messageId = new MessageId(messageIdByte);
 		width = in.readInt();
 		height = in.readInt();
+		mimeType = in.readString();
+		extension = in.readString();
 		thumbnailWidth = in.readInt();
 		thumbnailHeight = in.readInt();
 		hasError = in.readByte() != 0;
+		instanceId = in.readLong();
 	}
 
 	public MessageId getMessageId() {
@@ -63,6 +77,14 @@ public class AttachmentItem implements Parcelable {
 		return height;
 	}
 
+	String getMimeType() {
+		return mimeType;
+	}
+
+	String getExtension() {
+		return extension;
+	}
+
 	int getThumbnailWidth() {
 		return thumbnailWidth;
 	}
@@ -75,9 +97,8 @@ public class AttachmentItem implements Parcelable {
 		return hasError;
 	}
 
-	// TODO use counter instead, because in theory one attachment can appear in more than one messages
 	String getTransitionName() {
-		return String.valueOf(messageId.hashCode());
+		return String.valueOf(instanceId);
 	}
 
 	@Override
@@ -90,9 +111,18 @@ public class AttachmentItem implements Parcelable {
 		dest.writeByteArray(messageId.getBytes());
 		dest.writeInt(width);
 		dest.writeInt(height);
+		dest.writeString(mimeType);
+		dest.writeString(extension);
 		dest.writeInt(thumbnailWidth);
 		dest.writeInt(thumbnailHeight);
 		dest.writeByte((byte) (hasError ? 1 : 0));
+		dest.writeLong(instanceId);
+	}
+
+	@Override
+	public boolean equals(@Nullable Object o) {
+		return o instanceof AttachmentItem &&
+				instanceId == ((AttachmentItem) o).instanceId;
 	}
 
 }

briar-android/src/main/java/org/briarproject/briar/android/conversation/ConversationActivity.java

@@ -1,11 +1,14 @@
 package org.briarproject.briar.android.conversation;
 
+import android.annotation.SuppressLint;
 import android.arch.lifecycle.Observer;
 import android.arch.lifecycle.ViewModelProvider;
 import android.arch.lifecycle.ViewModelProviders;
 import android.content.DialogInterface;
 import android.content.Intent;
+import android.net.Uri;
 import android.os.Bundle;
+import android.os.Parcelable;
 import android.support.annotation.Nullable;
 import android.support.annotation.UiThread;
 import android.support.design.widget.Snackbar;
@@ -27,7 +30,6 @@ import android.widget.ImageView;
 import android.widget.TextView;
 import android.widget.Toast;
 
-import org.briarproject.bramble.api.FormatException;
 import org.briarproject.bramble.api.Pair;
 import org.briarproject.bramble.api.contact.ContactId;
 import org.briarproject.bramble.api.contact.ContactManager;
@@ -44,14 +46,10 @@ import org.briarproject.bramble.api.nullsafety.ParametersNotNullByDefault;
 import org.briarproject.bramble.api.plugin.ConnectionRegistry;
 import org.briarproject.bramble.api.plugin.event.ContactConnectedEvent;
 import org.briarproject.bramble.api.plugin.event.ContactDisconnectedEvent;
-import org.briarproject.bramble.api.settings.Settings;
 import org.briarproject.bramble.api.settings.SettingsManager;
-import org.briarproject.bramble.api.sync.GroupId;
-import org.briarproject.bramble.api.sync.Message;
 import org.briarproject.bramble.api.sync.MessageId;
 import org.briarproject.bramble.api.sync.event.MessagesAckedEvent;
 import org.briarproject.bramble.api.sync.event.MessagesSentEvent;
-import org.briarproject.bramble.util.StringUtils;
 import org.briarproject.briar.R;
 import org.briarproject.briar.android.activity.ActivityComponent;
 import org.briarproject.briar.android.activity.BriarActivity;
@@ -62,8 +60,12 @@ import org.briarproject.briar.android.forum.ForumActivity;
 import org.briarproject.briar.android.introduction.IntroductionActivity;
 import org.briarproject.briar.android.privategroup.conversation.GroupActivity;
 import org.briarproject.briar.android.view.BriarRecyclerView;
+import org.briarproject.briar.android.view.ImagePreview;
+import org.briarproject.briar.android.view.TextAttachmentController;
+import org.briarproject.briar.android.view.TextAttachmentController.AttachImageListener;
 import org.briarproject.briar.android.view.TextInputView;
-import org.briarproject.briar.android.view.TextInputView.TextInputListener;
+import org.briarproject.briar.android.view.TextSendController;
+import org.briarproject.briar.android.view.TextSendController.SendListener;
 import org.briarproject.briar.api.android.AndroidNotificationManager;
 import org.briarproject.briar.api.blog.BlogSharingManager;
 import org.briarproject.briar.api.client.ProtocolStateException;
@@ -78,7 +80,6 @@ import org.briarproject.briar.api.introduction.IntroductionManager;
 import org.briarproject.briar.api.messaging.Attachment;
 import org.briarproject.briar.api.messaging.AttachmentHeader;
 import org.briarproject.briar.api.messaging.MessagingManager;
-import org.briarproject.briar.api.messaging.PrivateMessage;
 import org.briarproject.briar.api.messaging.PrivateMessageFactory;
 import org.briarproject.briar.api.messaging.PrivateMessageHeader;
 import org.briarproject.briar.api.privategroup.invitation.GroupInvitationManager;
@@ -100,11 +101,12 @@ import im.delight.android.identicons.IdenticonDrawable;
 import uk.co.samuelwall.materialtaptargetprompt.MaterialTapTargetPrompt;
 import uk.co.samuelwall.materialtaptargetprompt.MaterialTapTargetPrompt.PromptStateChangeListener;
 
+import static android.arch.lifecycle.Lifecycle.State.STARTED;
 import static android.os.Build.VERSION.SDK_INT;
 import static android.support.v4.app.ActivityOptionsCompat.makeSceneTransitionAnimation;
 import static android.support.v4.view.ViewCompat.setTransitionName;
 import static android.support.v7.util.SortedList.INVALID_POSITION;
-import static android.view.Gravity.END;
+import static android.view.Gravity.RIGHT;
 import static android.widget.Toast.LENGTH_SHORT;
 import static java.util.Collections.emptyList;
 import static java.util.Collections.sort;
@@ -114,11 +116,14 @@ import static java.util.logging.Level.WARNING;
 import static org.briarproject.bramble.util.LogUtils.logDuration;
 import static org.briarproject.bramble.util.LogUtils.logException;
 import static org.briarproject.bramble.util.LogUtils.now;
+import static org.briarproject.bramble.util.StringUtils.isNullOrEmpty;
+import static org.briarproject.briar.android.TestingConstants.FEATURE_FLAG_IMAGE_ATTACHMENTS;
+import static org.briarproject.briar.android.activity.RequestCodes.REQUEST_ATTACH_IMAGE;
 import static org.briarproject.briar.android.activity.RequestCodes.REQUEST_INTRODUCTION;
-import static org.briarproject.briar.android.conversation.ImageActivity.ATTACHMENT;
+import static org.briarproject.briar.android.conversation.ImageActivity.ATTACHMENTS;
+import static org.briarproject.briar.android.conversation.ImageActivity.ATTACHMENT_POSITION;
 import static org.briarproject.briar.android.conversation.ImageActivity.DATE;
 import static org.briarproject.briar.android.conversation.ImageActivity.NAME;
-import static org.briarproject.briar.android.settings.SettingsFragment.SETTINGS_NAMESPACE;
 import static org.briarproject.briar.android.util.UiUtils.getAvatarTransitionName;
 import static org.briarproject.briar.android.util.UiUtils.getBulbTransitionName;
 import static org.briarproject.briar.android.util.UiUtils.observeOnce;
@@ -129,15 +134,16 @@ import static uk.co.samuelwall.materialtaptargetprompt.MaterialTapTargetPrompt.S
 @MethodsNotNullByDefault
 @ParametersNotNullByDefault
 public class ConversationActivity extends BriarActivity
-		implements EventListener, ConversationListener, TextInputListener,
-		TextCache, AttachmentCache {
+		implements EventListener, ConversationListener, SendListener,
+		TextCache, AttachmentCache, AttachImageListener {
 
 	public static final String CONTACT_ID = "briar.CONTACT_ID";
 
 	private static final Logger LOG =
 			Logger.getLogger(ConversationActivity.class.getName());
-	private static final String SHOW_ONBOARDING_INTRODUCTION =
-			"showOnboardingIntroduction";
+
+	private static final int TRANSITION_DURATION_MS = 500;
+	private static final int ONBOARDING_DELAY_MS = 250;
 
 	@Inject
 	AndroidNotificationManager notificationManager;
@@ -146,20 +152,8 @@ public class ConversationActivity extends BriarActivity
 	@Inject
 	@CryptoExecutor
 	Executor cryptoExecutor;
-
-	private final Map<MessageId, String> textCache = new ConcurrentHashMap<>();
-	private AttachmentController attachmentController;
-
-	private ConversationViewModel viewModel;
-	private ConversationVisitor visitor;
-	private ConversationAdapter adapter;
-	private Toolbar toolbar;
-	private CircleImageView toolbarAvatar;
-	private ImageView toolbarStatus;
-	private TextView toolbarTitle;
-	private BriarRecyclerView list;
-	private LinearLayoutManager layoutManager;
-	private TextInputView textInputView;
+	@Inject
+	ViewModelProvider.Factory viewModelFactory;
 
 	// Fields that are accessed from background threads must be volatile
 	@Inject
@@ -182,22 +176,37 @@ public class ConversationActivity extends BriarActivity
 	volatile BlogSharingManager blogSharingManager;
 	@Inject
 	volatile GroupInvitationManager groupInvitationManager;
-	@Inject
-	ViewModelProvider.Factory viewModelFactory;
-
-	private volatile ContactId contactId;
-	@Nullable
-	private volatile GroupId messagingGroupId;
 
+	private final Map<MessageId, String> textCache = new ConcurrentHashMap<>();
 	private final Observer<String> contactNameObserver = name -> {
 		requireNonNull(name);
 		loadMessages();
 	};
 
+	private AttachmentController attachmentController;
+	private ConversationViewModel viewModel;
+	private ConversationVisitor visitor;
+	private ConversationAdapter adapter;
+	private Toolbar toolbar;
+	private CircleImageView toolbarAvatar;
+	private ImageView toolbarStatus;
+	private TextView toolbarTitle;
+	private BriarRecyclerView list;
+	private LinearLayoutManager layoutManager;
+	private TextInputView textInputView;
+	private TextSendController sendController;
+	@Nullable
+	private Parcelable layoutManagerState;
+
+	private volatile ContactId contactId;
+
 	@Override
 	public void onCreate(@Nullable Bundle state) {
 		if (SDK_INT >= 21) {
-			Transition slide = new Slide(END);
+			// Spurious lint warning - using END causes a crash
+			@SuppressLint("RtlHardcoded")
+			Transition slide = new Slide(RIGHT);
+			slide.setDuration(TRANSITION_DURATION_MS);
 			setSceneTransitionAnimation(slide, null, slide);
 		}
 		super.onCreate(state);
@@ -209,7 +218,6 @@ public class ConversationActivity extends BriarActivity
 
 		viewModel = ViewModelProviders.of(this, viewModelFactory)
 				.get(ConversationViewModel.class);
-		viewModel.setContactId(contactId);
 		attachmentController = viewModel.getAttachmentController();
 
 		setContentView(R.layout.activity_conversation);
@@ -233,6 +241,8 @@ public class ConversationActivity extends BriarActivity
 			requireNonNull(deleted);
 			if (deleted) finish();
 		});
+		viewModel.getAddedPrivateMessage().observe(this,
+				this::onAddedPrivateMessage);
 
 		setTransitionName(toolbarAvatar, getAvatarTransitionName(contactId));
 		setTransitionName(toolbarStatus, getBulbTransitionName(contactId));
@@ -245,9 +255,34 @@ public class ConversationActivity extends BriarActivity
 		list.setLayoutManager(layoutManager);
 		list.setAdapter(adapter);
 		list.setEmptyText(getString(R.string.no_private_messages));
+		ConversationScrollListener scrollListener =
+				new ConversationScrollListener(adapter, viewModel);
+		list.getRecyclerView().addOnScrollListener(scrollListener);
 
 		textInputView = findViewById(R.id.text_input_container);
-		textInputView.setListener(this);
+		if (FEATURE_FLAG_IMAGE_ATTACHMENTS) {
+			ImagePreview imagePreview = findViewById(R.id.imagePreview);
+			sendController = new TextAttachmentController(textInputView,
+					imagePreview, this, this);
+			observeOnce(viewModel.hasImageSupport(), this, hasSupport -> {
+				if (hasSupport != null && hasSupport) {
+					// remove cast when removing FEATURE_FLAG_IMAGE_ATTACHMENTS
+					((TextAttachmentController) sendController)
+							.setImagesSupported();
+				}
+			});
+		} else {
+			sendController = new TextSendController(textInputView, this, false);
+		}
+		textInputView.setSendController(sendController);
+		textInputView.setMaxTextLength(MAX_PRIVATE_MESSAGE_TEXT_LENGTH);
+		textInputView.setEnabled(false);
+		textInputView.addOnKeyboardShownListener(this::scrollToBottom);
+	}
+
+	private void scrollToBottom() {
+		int items = adapter.getItemCount();
+		if (items > 0) list.scrollToPosition(items - 1);
 	}
 
 	@Override
@@ -256,7 +291,8 @@ public class ConversationActivity extends BriarActivity
 	}
 
 	@Override
-	protected void onActivityResult(int request, int result, Intent data) {
+	protected void onActivityResult(int request, int result,
+			@Nullable Intent data) {
 		super.onActivityResult(request, result, data);
 
 		if (request == REQUEST_INTRODUCTION && result == RESULT_OK) {
@@ -264,6 +300,9 @@ public class ConversationActivity extends BriarActivity
 					Snackbar.LENGTH_SHORT);
 			snackbar.getView().setBackgroundResource(R.color.briar_primary);
 			snackbar.show();
+		} else if (request == REQUEST_ATTACH_IMAGE && result == RESULT_OK) {
+			// remove cast when removing FEATURE_FLAG_IMAGE_ATTACHMENTS
+			((TextAttachmentController) sendController).onImageReceived(data);
 		}
 	}
 
@@ -278,6 +317,16 @@ public class ConversationActivity extends BriarActivity
 		list.startPeriodicUpdate();
 	}
 
+	@Override
+	public void onResume() {
+		super.onResume();
+		// Trigger loading of contact data, noop if data was loaded already.
+		//
+		// We can only start loading data *after* we are sure
+		// the user has signed in. After sign-in, onCreate() isn't run again.
+		if (signedIn()) viewModel.setContactId(contactId);
+	}
+
 	@Override
 	public void onStop() {
 		super.onStop();
@@ -287,16 +336,39 @@ public class ConversationActivity extends BriarActivity
 		list.stopPeriodicUpdate();
 	}
 
+	@Override
+	protected void onSaveInstanceState(Bundle outState) {
+		super.onSaveInstanceState(outState);
+		if (layoutManager != null) {
+			layoutManagerState = layoutManager.onSaveInstanceState();
+			outState.putParcelable("layoutManager", layoutManagerState);
+		}
+	}
+
+	@Override
+	protected void onRestoreInstanceState(Bundle savedInstanceState) {
+		super.onRestoreInstanceState(savedInstanceState);
+		layoutManagerState = savedInstanceState.getParcelable("layoutManager");
+	}
+
 	@Override
 	public boolean onCreateOptionsMenu(Menu menu) {
 		// Inflate the menu items for use in the action bar
 		MenuInflater inflater = getMenuInflater();
 		inflater.inflate(R.menu.conversation_actions, menu);
 
-		enableIntroductionActionIfAvailable(
-				menu.findItem(R.id.action_introduction));
-		enableAliasActionIfAvailable(
-				menu.findItem(R.id.action_set_alias));
+		// enable introduction action if available
+		observeOnce(viewModel.showIntroductionAction(), this, enable -> {
+			if (enable != null && enable) {
+				menu.findItem(R.id.action_introduction).setEnabled(true);
+				// show introduction onboarding, if needed
+				observeOnce(viewModel.showIntroductionOnboarding(), this,
+						this::showIntroductionOnboarding);
+			}
+		});
+		// enable alias action if available
+		observeOnce(viewModel.getContact(), this, contact ->
+				menu.findItem(R.id.action_set_alias).setEnabled(true));
 
 		return super.onCreateOptionsMenu(menu);
 	}
@@ -359,33 +431,10 @@ public class ConversationActivity extends BriarActivity
 						Long.compare(b.getTimestamp(), a.getTimestamp()));
 				if (!sorted.isEmpty()) {
 					// If the latest header is a private message, eagerly load
-					// its text so we can set the scroll position correctly
+					// its size so we can set the scroll position correctly
 					ConversationMessageHeader latest = sorted.get(0);
 					if (latest instanceof PrivateMessageHeader) {
-						MessageId id = latest.getId();
-						PrivateMessageHeader h = (PrivateMessageHeader) latest;
-						if (h.hasText()) {
-							String text = textCache.get(id);
-							if (text == null) {
-								LOG.info(
-										"Eagerly loading text of latest message");
-								text = messagingManager.getMessageText(id);
-								textCache.put(id, text);
-							}
-						}
-						if (!h.getAttachmentHeaders().isEmpty()) {
-							List<AttachmentItem> items =
-									attachmentController.get(id);
-							if (items == null) {
-								LOG.info(
-										"Eagerly loading image size for latest message");
-								items = attachmentController.getAttachmentItems(
-										attachmentController
-												.getMessageAttachments(
-														h.getAttachmentHeaders()));
-								attachmentController.put(id, items);
-							}
-						}
+						eagerlyLoadMessageSize((PrivateMessageHeader) latest);
 					}
 				}
 				displayMessages(revision, sorted);
@@ -397,17 +446,51 @@ public class ConversationActivity extends BriarActivity
 		});
 	}
 
+	private void eagerlyLoadMessageSize(PrivateMessageHeader h)
+			throws DbException {
+		MessageId id = h.getId();
+		// If the message has text, load it
+		if (h.hasText()) {
+			String text = textCache.get(id);
+			if (text == null) {
+				LOG.info("Eagerly loading text for latest message");
+				text = messagingManager.getMessageText(id);
+				textCache.put(id, text);
+			}
+		}
+		// If the message has a single image, load its size - for multiple
+		// images we use a grid so the size is fixed
+		if (h.getAttachmentHeaders().size() == 1) {
+			List<AttachmentItem> items = attachmentController.get(id);
+			if (items == null) {
+				LOG.info("Eagerly loading image size for latest message");
+				items = attachmentController.getAttachmentItems(
+						attachmentController.getMessageAttachments(
+								h.getAttachmentHeaders()));
+				attachmentController.put(id, items);
+			}
+		}
+	}
+
 	private void displayMessages(int revision,
 			Collection<ConversationMessageHeader> headers) {
 		runOnUiThreadUnlessDestroyed(() -> {
 			if (revision == adapter.getRevision()) {
 				adapter.incrementRevision();
-				textInputView.setSendButtonEnabled(true);
+				textInputView.setEnabled(true);
+				// start observing onboarding after enabling (only once, because
+				// we only update this when an onboarding should be shown)
+				observeOnce(viewModel.showImageOnboarding(), this,
+						this::showImageOnboarding);
 				List<ConversationItem> items = createItems(headers);
 				adapter.addAll(items);
 				list.showData();
-				// Scroll to the bottom
-				list.scrollToPosition(adapter.getItemCount() - 1);
+				if (layoutManagerState == null) {
+					scrollToBottom();
+				} else {
+					// Restore the previous scroll position
+					layoutManager.onRestoreInstanceState(layoutManagerState);
+				}
 			} else {
 				LOG.info("Concurrent update, reloading");
 				loadMessages();
@@ -448,21 +531,28 @@ public class ConversationActivity extends BriarActivity
 			Pair<Integer, ConversationMessageItem> pair =
 					adapter.getMessageItem(m);
 			if (pair != null) {
+				boolean scroll = shouldScrollWhenUpdatingMessage();
 				pair.getSecond().setText(text);
-				boolean bottom = adapter.isScrolledToBottom(layoutManager);
 				adapter.notifyItemChanged(pair.getFirst());
-				if (bottom) list.scrollToPosition(adapter.getItemCount() - 1);
+				if (scroll) scrollToBottom();
 			}
 		});
 	}
 
+	// When a message's text or attachments are loaded, scroll to the bottom
+	// if the conversation is visible and we were previously at the bottom
+	private boolean shouldScrollWhenUpdatingMessage() {
+		return getLifecycle().getCurrentState().isAtLeast(STARTED)
+				&& adapter.isScrolledToBottom(layoutManager);
+	}
+
 	private void loadMessageAttachments(MessageId messageId,
 			List<AttachmentHeader> headers) {
 		runOnDbThread(() -> {
 			try {
 				List<Pair<AttachmentHeader, Attachment>> attachments =
 						attachmentController.getMessageAttachments(headers);
-				// TODO move getting the items off to the IoExecutor
+				// TODO move getting the items off to IoExecutor, if size == 1
 				List<AttachmentItem> items =
 						attachmentController.getAttachmentItems(attachments);
 				displayMessageAttachments(messageId, items);
@@ -479,10 +569,10 @@ public class ConversationActivity extends BriarActivity
 			Pair<Integer, ConversationMessageItem> pair =
 					adapter.getMessageItem(m);
 			if (pair != null) {
+				boolean scroll = shouldScrollWhenUpdatingMessage();
 				pair.getSecond().setAttachments(items);
-				boolean bottom = adapter.isScrolledToBottom(layoutManager);
 				adapter.notifyItemChanged(pair.getFirst());
-				if (bottom) list.scrollToPosition(adapter.getItemCount() - 1);
+				if (scroll) scrollToBottom();
 			}
 		});
 	}
@@ -531,10 +621,13 @@ public class ConversationActivity extends BriarActivity
 
 	private void addConversationItem(ConversationItem item) {
 		runOnUiThreadUnlessDestroyed(() -> {
-			boolean bottom = adapter.isScrolledToBottom(layoutManager);
 			adapter.incrementRevision();
 			adapter.add(item);
-			if (bottom) list.scrollToPosition(adapter.getItemCount() - 1);
+			// When adding a new message, scroll to the bottom if the
+			// conversation is visible, even if we're not currently at
+			// the bottom
+			if (getLifecycle().getCurrentState().isAtLeast(STARTED))
+				scrollToBottom();
 		});
 	}
 
@@ -570,14 +663,18 @@ public class ConversationActivity extends BriarActivity
 	}
 
 	@Override
-	public void onSendClick(String text) {
-		if (text.isEmpty()) return;
-		text = StringUtils.truncateUtf8(text, MAX_PRIVATE_MESSAGE_TEXT_LENGTH);
+	public void onAttachImage(Intent intent) {
+		startActivityForResult(intent, REQUEST_ATTACH_IMAGE);
+	}
+
+	@Override
+	public void onSendClick(@Nullable String text, List<Uri> imageUris) {
+		if (isNullOrEmpty(text) && imageUris.isEmpty())
+			throw new AssertionError();
 		long timestamp = System.currentTimeMillis();
 		timestamp = Math.max(timestamp, getMinTimestampForNewMessage());
-		if (messagingGroupId == null) loadGroupId(text, timestamp);
-		else createMessage(text, timestamp);
-		textInputView.setText("");
+		viewModel.sendMessage(text, imageUris, timestamp);
+		textInputView.clearText();
 	}
 
 	private long getMinTimestampForNewMessage() {
@@ -586,48 +683,10 @@ public class ConversationActivity extends BriarActivity
 		return item == null ? 0 : item.getTime() + 1;
 	}
 
-	private void loadGroupId(String text, long timestamp) {
-		runOnDbThread(() -> {
-			try {
-				messagingGroupId =
-						messagingManager.getConversationId(contactId);
-				createMessage(text, timestamp);
-			} catch (DbException e) {
-				logException(LOG, WARNING, e);
-			}
-
-		});
-	}
-
-	private void createMessage(String text, long timestamp) {
-		cryptoExecutor.execute(() -> {
-			try {
-				//noinspection ConstantConditions init in loadGroupId()
-				storeMessage(privateMessageFactory.createPrivateMessage(
-						messagingGroupId, timestamp, text, emptyList()), text);
-			} catch (FormatException e) {
-				throw new RuntimeException(e);
-			}
-		});
-	}
-
-	private void storeMessage(PrivateMessage m, String text) {
-		runOnDbThread(() -> {
-			try {
-				long start = now();
-				messagingManager.addLocalMessage(m);
-				logDuration(LOG, "Storing message", start);
-				Message message = m.getMessage();
-				PrivateMessageHeader h = new PrivateMessageHeader(
-						message.getId(), message.getGroupId(),
-						message.getTimestamp(), true, false, false, false,
-						true, emptyList());
-				textCache.put(message.getId(), text);
-				addConversationItem(h.accept(visitor));
-			} catch (DbException e) {
-				logException(LOG, WARNING, e);
-			}
-		});
+	private void onAddedPrivateMessage(@Nullable PrivateMessageHeader h) {
+		if (h == null) return;
+		addConversationItem(h.accept(visitor));
+		viewModel.onAddedPrivateMessageSeen();
 	}
 
 	private void askToRemoveContact() {
@@ -664,91 +723,70 @@ public class ConversationActivity extends BriarActivity
 		});
 	}
 
-	private void enableIntroductionActionIfAvailable(MenuItem item) {
-		runOnDbThread(() -> {
-			try {
-				if (contactManager.getActiveContacts().size() > 1) {
-					enableIntroductionAction(item);
-					Settings settings =
-							settingsManager.getSettings(SETTINGS_NAMESPACE);
-					if (settings.getBoolean(SHOW_ONBOARDING_INTRODUCTION,
-							true)) {
-						showIntroductionOnboarding();
-					}
-				}
-			} catch (DbException e) {
-				logException(LOG, WARNING, e);
-			}
-		});
+	private void showImageOnboarding(@Nullable Boolean show) {
+		if (show == null || !show) return;
+		if (SDK_INT >= 21) {
+			// show onboarding only after the enter transition has ended
+			// otherwise the tap target animation won't play
+			textInputView.postDelayed(this::showImageOnboarding,
+					TRANSITION_DURATION_MS + ONBOARDING_DELAY_MS);
+		} else {
+			showImageOnboarding();
+		}
 	}
 
-	private void enableAliasActionIfAvailable(MenuItem item) {
-		observeOnce(viewModel.getContact(), this, c -> item.setEnabled(true));
+	private void showImageOnboarding() {
+		// remove cast when removing FEATURE_FLAG_IMAGE_ATTACHMENTS
+		((TextAttachmentController) sendController)
+				.showImageOnboarding(this, () ->
+						viewModel.onImageOnboardingSeen());
 	}
 
-	private void enableIntroductionAction(MenuItem item) {
-		runOnUiThreadUnlessDestroyed(() -> item.setEnabled(true));
+	private void showIntroductionOnboarding(@Nullable Boolean show) {
+		if (show == null || !show) return;
+		if (SDK_INT >= 21) {
+			// show onboarding only after the enter transition has ended
+			// otherwise the tap target animation won't play
+			textInputView.postDelayed(this::showIntroductionOnboarding,
+					TRANSITION_DURATION_MS + ONBOARDING_DELAY_MS);
+		} else {
+			showIntroductionOnboarding();
+		}
 	}
 
 	private void showIntroductionOnboarding() {
-		runOnUiThreadUnlessDestroyed(() -> {
-			// find view of overflow icon
-			View target = null;
-			for (int i = 0; i < toolbar.getChildCount(); i++) {
-				if (toolbar.getChildAt(i) instanceof ActionMenuView) {
-					ActionMenuView menu =
-							(ActionMenuView) toolbar.getChildAt(i);
-					target = menu.getChildAt(menu.getChildCount() - 1);
-					break;
-				}
+		// find view of overflow icon
+		View target = null;
+		for (int i = 0; i < toolbar.getChildCount(); i++) {
+			if (toolbar.getChildAt(i) instanceof ActionMenuView) {
+				ActionMenuView menu = (ActionMenuView) toolbar.getChildAt(i);
+				// The overflow icon should be the last child of the menu
+				target = menu.getChildAt(menu.getChildCount() - 1);
+				// If the menu hasn't been populated yet, use the menu itself
+				// as the target
+				if (target == null) target = menu;
+				break;
 			}
-			if (target == null) {
-				LOG.warning("No Overflow Icon found!");
-				return;
+		}
+		if (target == null) {
+			LOG.warning("No Overflow Icon found!");
+			return;
+		}
+
+		PromptStateChangeListener listener = (prompt, state) -> {
+			if (state == STATE_DISMISSED || state == STATE_FINISHED) {
+				viewModel.onIntroductionOnboardingSeen();
 			}
-
-			PromptStateChangeListener listener = (prompt, state) -> {
-				if (state == STATE_DISMISSED || state == STATE_FINISHED) {
-					introductionOnboardingSeen();
-				}
-			};
-			new MaterialTapTargetPrompt.Builder(ConversationActivity.this,
-					R.style.OnboardingDialogTheme).setTarget(target)
-					.setPrimaryText(R.string.introduction_onboarding_title)
-					.setSecondaryText(R.string.introduction_onboarding_text)
-					.setIcon(R.drawable.ic_more_vert_accent)
-					.setPromptStateChangeListener(listener)
-					.show();
-		});
-	}
-
-	private void introductionOnboardingSeen() {
-		runOnDbThread(() -> {
-			try {
-				Settings settings = new Settings();
-				settings.putBoolean(SHOW_ONBOARDING_INTRODUCTION, false);
-				settingsManager.mergeSettings(settings, SETTINGS_NAMESPACE);
-			} catch (DbException e) {
-				logException(LOG, WARNING, e);
-			}
-		});
-	}
-
-	@Override
-	public void onItemVisible(ConversationItem item) {
-		if (!item.isRead()) markMessageRead(item.getGroupId(), item.getId());
-	}
-
-	private void markMessageRead(GroupId g, MessageId m) {
-		runOnDbThread(() -> {
-			try {
-				long start = now();
-				messagingManager.setReadFlag(g, m, true);
-				logDuration(LOG, "Marking read", start);
-			} catch (DbException e) {
-				logException(LOG, WARNING, e);
-			}
-		});
+		};
+		new MaterialTapTargetPrompt.Builder(ConversationActivity.this,
+				R.style.OnboardingDialogTheme).setTarget(target)
+				.setPrimaryText(R.string.introduction_onboarding_title)
+				.setSecondaryText(R.string.introduction_onboarding_text)
+				.setIcon(R.drawable.ic_more_vert_accent)
+				.setBackgroundColour(
+						ContextCompat.getColor(this, R.color.briar_primary))
+				.setPromptStateChangeListener(listener)
+				.show();
 	}
 
 	@UiThread
@@ -825,19 +863,18 @@ public class ConversationActivity extends BriarActivity
 		} else {
 			name = getString(R.string.you);
 		}
+		ArrayList<AttachmentItem> attachments =
+				new ArrayList<>(messageItem.getAttachments());
 		Intent i = new Intent(this, ImageActivity.class);
-		i.putExtra(ATTACHMENT, item);
+		i.putParcelableArrayListExtra(ATTACHMENTS, attachments);
+		i.putExtra(ATTACHMENT_POSITION, attachments.indexOf(item));
 		i.putExtra(NAME, name);
 		i.putExtra(DATE, messageItem.getTime());
-		if (SDK_INT >= 23) {
-			String transitionName = item.getTransitionName();
-			ActivityOptionsCompat options =
-					makeSceneTransitionAnimation(this, view, transitionName);
-			ActivityCompat.startActivity(this, i, options.toBundle());
-		} else {
-			// work-around for android bug #224270
-			startActivity(i);
-		}
+		// restoring list position should not trigger android bug #224270
+		String transitionName = item.getTransitionName();
+		ActivityOptionsCompat options =
+				makeSceneTransitionAnimation(this, view, transitionName);
+		ActivityCompat.startActivity(this, i, options.toBundle());
 	}
 
 	@DatabaseExecutor

briar-android/src/main/java/org/briarproject/briar/android/conversation/ConversationAdapter.java

@@ -3,6 +3,7 @@ package org.briarproject.briar.android.conversation;
 import android.content.Context;
 import android.support.annotation.LayoutRes;
 import android.support.v7.widget.LinearLayoutManager;
+import android.support.v7.widget.RecyclerView.RecycledViewPool;
 import android.util.SparseArray;
 import android.view.LayoutInflater;
 import android.view.View;
@@ -13,19 +14,27 @@ import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
 import org.briarproject.bramble.api.sync.MessageId;
 import org.briarproject.briar.R;
 import org.briarproject.briar.android.util.BriarAdapter;
+import org.briarproject.briar.android.util.ItemReturningAdapter;
 
 import javax.annotation.Nullable;
 
 @NotNullByDefault
 class ConversationAdapter
-		extends BriarAdapter<ConversationItem, ConversationItemViewHolder> {
+		extends BriarAdapter<ConversationItem, ConversationItemViewHolder>
+		implements ItemReturningAdapter<ConversationItem> {
 
 	private ConversationListener listener;
+	private final RecycledViewPool imageViewPool;
+	private final ImageItemDecoration imageItemDecoration;
 
 	ConversationAdapter(Context ctx,
 			ConversationListener conversationListener) {
 		super(ctx, ConversationItem.class);
 		listener = conversationListener;
+		// This shares the same pool for view recycling between all image lists
+		imageViewPool = new RecycledViewPool();
+		// Share the item decoration as well
+		imageItemDecoration = new ImageItemDecoration(ctx);
 	}
 
 	@LayoutRes
@@ -42,15 +51,17 @@ class ConversationAdapter
 				type, viewGroup, false);
 		switch (type) {
 			case R.layout.list_item_conversation_msg_in:
-				return new ConversationMessageViewHolder(v, true);
+				return new ConversationMessageViewHolder(v, listener, true,
+						imageViewPool, imageItemDecoration);
 			case R.layout.list_item_conversation_msg_out:
-				return new ConversationMessageViewHolder(v, false);
+				return new ConversationMessageViewHolder(v, listener, false,
+						imageViewPool, imageItemDecoration);
 			case R.layout.list_item_conversation_notice_in:
-				return new ConversationNoticeViewHolder(v, true);
+				return new ConversationNoticeViewHolder(v, listener, true);
 			case R.layout.list_item_conversation_notice_out:
-				return new ConversationNoticeViewHolder(v, false);
+				return new ConversationNoticeViewHolder(v, listener, false);
 			case R.layout.list_item_conversation_request:
-				return new ConversationRequestViewHolder(v, true);
+				return new ConversationRequestViewHolder(v, listener, true);
 			default:
 				throw new IllegalArgumentException("Unknown ConversationItem");
 		}
@@ -59,8 +70,7 @@ class ConversationAdapter
 	@Override
 	public void onBindViewHolder(ConversationItemViewHolder ui, int position) {
 		ConversationItem item = items.get(position);
-		ui.bind(item, listener);
-		listener.onItemVisible(item);
+		ui.bind(item);
 	}
 
 	@Override

briar-android/src/main/java/org/briarproject/briar/android/conversation/ConversationItem.java

@@ -69,6 +69,10 @@ abstract class ConversationItem {
 		return read;
 	}
 
+	void markRead() {
+		read = true;
+	}
+
 	/**
 	 * Only useful for outgoing messages.
 	 */

briar-android/src/main/java/org/briarproject/briar/android/conversation/ConversationItemViewHolder.java

@@ -18,14 +18,17 @@ import static org.briarproject.briar.android.util.UiUtils.formatDate;
 @NotNullByDefault
 abstract class ConversationItemViewHolder extends ViewHolder {
 
+	protected final ConversationListener listener;
 	protected final ConstraintLayout layout;
 	@Nullable
 	private final OutItemViewHolder outViewHolder;
 	private final TextView text;
 	protected final TextView time;
 
-	ConversationItemViewHolder(View v, boolean isIncoming) {
+	ConversationItemViewHolder(View v, ConversationListener listener,
+			boolean isIncoming) {
 		super(v);
+		this.listener = listener;
 		this.outViewHolder = isIncoming ? null : new OutItemViewHolder(v);
 		layout = v.findViewById(R.id.layout);
 		text = v.findViewById(R.id.text);
@@ -33,7 +36,7 @@ abstract class ConversationItemViewHolder extends ViewHolder {
 	}
 
 	@CallSuper
-	void bind(ConversationItem item, ConversationListener listener) {
+	void bind(ConversationItem item) {
 		if (item.getText() != null) {
 			text.setText(trim(item.getText()));
 		}

briar-android/src/main/java/org/briarproject/briar/android/conversation/ConversationListener.java

@@ -9,8 +9,6 @@ import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
 @NotNullByDefault
 interface ConversationListener {
 
-	void onItemVisible(ConversationItem item);
-
 	void respondToRequest(ConversationRequestItem item, boolean accept);
 
 	void openRequestedShareable(ConversationRequestItem item);

briar-android/src/main/java/org/briarproject/briar/android/conversation/ConversationMessageViewHolder.java

@@ -1,63 +1,45 @@
 package org.briarproject.briar.android.conversation;
 
-import android.content.res.Configuration;
-import android.graphics.Bitmap;
-import android.support.annotation.DrawableRes;
 import android.support.annotation.UiThread;
 import android.support.constraint.ConstraintSet;
-import android.support.v4.content.ContextCompat;
+import android.support.v7.widget.RecyclerView;
+import android.support.v7.widget.RecyclerView.RecycledViewPool;
 import android.view.View;
 import android.view.ViewGroup;
-import android.widget.ImageView;
-
-import com.bumptech.glide.load.Transformation;
 
 import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
 import org.briarproject.briar.R;
-import org.briarproject.briar.android.conversation.glide.BriarImageTransformation;
-import org.briarproject.briar.android.conversation.glide.GlideApp;
 
-import static android.os.Build.VERSION.SDK_INT;
-import static android.support.v4.view.ViewCompat.LAYOUT_DIRECTION_RTL;
-import static com.bumptech.glide.load.engine.DiskCacheStrategy.NONE;
-import static com.bumptech.glide.load.resource.drawable.DrawableTransitionOptions.withCrossFade;
+import static android.support.constraint.ConstraintSet.WRAP_CONTENT;
+import static android.support.v4.content.ContextCompat.getColor;
 
 @UiThread
 @NotNullByDefault
 class ConversationMessageViewHolder extends ConversationItemViewHolder {
 
-	@DrawableRes
-	private static final int ERROR_RES = R.drawable.ic_image_broken;
-
-	private final ImageView imageView;
+	private final ImageAdapter adapter;
 	private final ViewGroup statusLayout;
 	private final int timeColor, timeColorBubble;
-	private final int radiusBig, radiusSmall;
-	private final boolean isRtl;
 	private final ConstraintSet textConstraints = new ConstraintSet();
 	private final ConstraintSet imageConstraints = new ConstraintSet();
 	private final ConstraintSet imageTextConstraints = new ConstraintSet();
 
-	ConversationMessageViewHolder(View v, boolean isIncoming) {
-		super(v, isIncoming);
-		imageView = v.findViewById(R.id.imageView);
+	ConversationMessageViewHolder(View v, ConversationListener listener,
+			boolean isIncoming, RecycledViewPool imageViewPool,
+			ImageItemDecoration imageItemDecoration) {
+		super(v, listener, isIncoming);
 		statusLayout = v.findViewById(R.id.statusLayout);
-		radiusBig = v.getContext().getResources()
-				.getDimensionPixelSize(R.dimen.message_bubble_radius_big);
-		radiusSmall = v.getContext().getResources()
-				.getDimensionPixelSize(R.dimen.message_bubble_radius_small);
+
+		// image list
+		RecyclerView list = v.findViewById(R.id.imageList);
+		list.setRecycledViewPool(imageViewPool);
+		adapter = new ImageAdapter(v.getContext(), listener);
+		list.setAdapter(adapter);
+		list.addItemDecoration(imageItemDecoration);
 
 		// remember original status text color
 		timeColor = time.getCurrentTextColor();
-		timeColorBubble =
-				ContextCompat.getColor(v.getContext(), R.color.briar_white);
-
-		// find out if we are showing a RTL language, Use the configuration,
-		// because getting the layout direction of views is not reliable
-		Configuration config =
-				imageView.getContext().getResources().getConfiguration();
-		isRtl = SDK_INT >= 17 &&
-				config.getLayoutDirection() == LAYOUT_DIRECTION_RTL;
+		timeColorBubble = getColor(v.getContext(), R.color.briar_white);
 
 		// clone constraint sets from layout files
 		textConstraints
@@ -77,85 +59,55 @@ class ConversationMessageViewHolder extends ConversationItemViewHolder {
 	}
 
 	@Override
-	void bind(ConversationItem conversationItem,
-			ConversationListener listener) {
-		super.bind(conversationItem, listener);
+	void bind(ConversationItem conversationItem) {
+		super.bind(conversationItem);
 		ConversationMessageItem item =
 				(ConversationMessageItem) conversationItem;
 		if (item.getAttachments().isEmpty()) {
 			bindTextItem();
 		} else {
-			bindImageItem(item, listener);
+			bindImageItem(item);
 		}
 	}
 
 	private void bindTextItem() {
-		clearImage();
+		resetStatusLayoutForText();
+		textConstraints.applyTo(layout);
+		adapter.clear();
+	}
+
+	private void bindImageItem(ConversationMessageItem item) {
+		ConstraintSet constraintSet;
+		if (item.getText() == null) {
+			statusLayout.setBackgroundResource(R.drawable.msg_status_bubble);
+			time.setTextColor(timeColorBubble);
+			constraintSet = imageConstraints;
+		} else {
+			resetStatusLayoutForText();
+			constraintSet = imageTextConstraints;
+		}
+
+		if (item.getAttachments().size() == 1) {
+			// apply image size constraints for a single image
+			AttachmentItem attachment = item.getAttachments().get(0);
+			int width = attachment.getThumbnailWidth();
+			int height = attachment.getThumbnailHeight();
+			constraintSet.constrainWidth(R.id.imageList, width);
+			constraintSet.constrainHeight(R.id.imageList, height);
+		} else {
+			// bubble adapts to size of image list
+			constraintSet.constrainWidth(R.id.imageList, WRAP_CONTENT);
+			constraintSet.constrainHeight(R.id.imageList, WRAP_CONTENT);
+		}
+		constraintSet.applyTo(layout);
+		adapter.setConversationItem(item);
+	}
+
+	private void resetStatusLayoutForText() {
 		statusLayout.setBackgroundResource(0);
 		// also reset padding (the background drawable defines some)
 		statusLayout.setPadding(0, 0, 0, 0);
 		time.setTextColor(timeColor);
-		textConstraints.applyTo(layout);
-	}
-
-	private void bindImageItem(ConversationMessageItem item,
-			ConversationListener listener) {
-		// TODO show more than just the first image
-		AttachmentItem attachment = item.getAttachments().get(0);
-
-		ConstraintSet constraintSet;
-		if (item.getText() == null) {
-			statusLayout
-					.setBackgroundResource(R.drawable.msg_status_bubble);
-			time.setTextColor(timeColorBubble);
-			constraintSet = imageConstraints;
-		} else {
-			statusLayout.setBackgroundResource(0);
-			// also reset padding (the background drawable defines some)
-			statusLayout.setPadding(0, 0, 0, 0);
-			time.setTextColor(timeColor);
-			constraintSet = imageTextConstraints;
-		}
-
-		// apply image size constraints, so glides picks them up for scaling
-		int width = attachment.getThumbnailWidth();
-		int height = attachment.getThumbnailHeight();
-		constraintSet.constrainWidth(R.id.imageView, width);
-		constraintSet.constrainHeight(R.id.imageView, height);
-		constraintSet.applyTo(layout);
-
-		if (attachment.hasError()) {
-			clearImage();
-			imageView.setImageResource(ERROR_RES);
-		} else {
-			loadImage(item, attachment, listener);
-		}
-	}
-
-	private void clearImage() {
-		GlideApp.with(imageView)
-				.clear(imageView);
-		imageView.setOnClickListener(null);
-	}
-
-	private void loadImage(ConversationMessageItem item,
-			AttachmentItem attachment, ConversationListener listener) {
-		boolean leftCornerSmall =
-				(isIncoming() && !isRtl) || (!isIncoming() && isRtl);
-		boolean bottomRound = item.getText() == null;
-		Transformation<Bitmap> transformation = new BriarImageTransformation(
-				radiusSmall, radiusBig, leftCornerSmall, bottomRound);
-
-		GlideApp.with(imageView)
-				.load(attachment)
-				.diskCacheStrategy(NONE)
-				.error(ERROR_RES)
-				.transform(transformation)
-				.transition(withCrossFade())
-				.into(imageView)
-				.waitForLayout();
-		imageView.setOnClickListener(
-				view -> listener.onAttachmentClicked(view, item, attachment));
 	}
 
 }

briar-android/src/main/java/org/briarproject/briar/android/conversation/ConversationNoticeViewHolder.java

@@ -19,16 +19,17 @@ class ConversationNoticeViewHolder extends ConversationItemViewHolder {
 
 	private final TextView msgText;
 
-	ConversationNoticeViewHolder(View v, boolean isIncoming) {
-		super(v, isIncoming);
+	ConversationNoticeViewHolder(View v, ConversationListener listener,
+			boolean isIncoming) {
+		super(v, listener, isIncoming);
 		msgText = v.findViewById(R.id.msgText);
 	}
 
 	@Override
 	@CallSuper
-	void bind(ConversationItem item, ConversationListener listener) {
+	void bind(ConversationItem item) {
 		ConversationNoticeItem notice = (ConversationNoticeItem) item;
-		super.bind(notice, listener);
+		super.bind(notice);
 
 		String text = notice.getMsgText();
 		if (isNullOrEmpty(text)) {

briar-android/src/main/java/org/briarproject/briar/android/conversation/ConversationRequestViewHolder.java

@@ -17,16 +17,17 @@ class ConversationRequestViewHolder extends ConversationNoticeViewHolder {
 	private final Button acceptButton;
 	private final Button declineButton;
 
-	ConversationRequestViewHolder(View v, boolean isIncoming) {
-		super(v, isIncoming);
+	ConversationRequestViewHolder(View v, ConversationListener listener,
+			boolean isIncoming) {
+		super(v, listener, isIncoming);
 		acceptButton = v.findViewById(R.id.acceptButton);
 		declineButton = v.findViewById(R.id.declineButton);
 	}
 
 	@Override
-	void bind(ConversationItem item, ConversationListener listener) {
+	void bind(ConversationItem item) {
 		ConversationRequestItem request = (ConversationRequestItem) item;
-		super.bind(request, listener);
+		super.bind(request);
 
 		if (request.wasAnswered() && request.canBeOpened()) {
 			acceptButton.setVisibility(VISIBLE);

briar-android/src/main/java/org/briarproject/briar/android/conversation/ConversationScrollListener.java

@@ -0,0 +1,26 @@
+package org.briarproject.briar.android.conversation;
+
+import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
+import org.briarproject.briar.android.view.BriarRecyclerViewScrollListener;
+
+@NotNullByDefault
+class ConversationScrollListener extends
+		BriarRecyclerViewScrollListener<ConversationAdapter, ConversationItem> {
+
+	private final ConversationViewModel viewModel;
+
+	protected ConversationScrollListener(ConversationAdapter adapter,
+			ConversationViewModel viewModel) {
+		super(adapter);
+		this.viewModel = viewModel;
+	}
+
+	@Override
+	protected void onItemVisible(ConversationItem item) {
+		if (!item.isRead()) {
+			viewModel.markMessageRead(item.getGroupId(), item.getId());
+			item.markRead();
+		}
+	}
+
+}

briar-android/src/main/java/org/briarproject/briar/android/conversation/ConversationViewModel.java

@@ -5,19 +5,41 @@ import android.arch.lifecycle.AndroidViewModel;
 import android.arch.lifecycle.LiveData;
 import android.arch.lifecycle.MutableLiveData;
 import android.arch.lifecycle.Transformations;
+import android.content.ContentResolver;
+import android.net.Uri;
 import android.support.annotation.Nullable;
+import android.support.annotation.UiThread;
 
+import org.briarproject.bramble.api.FormatException;
+import org.briarproject.bramble.api.Pair;
 import org.briarproject.bramble.api.contact.Contact;
 import org.briarproject.bramble.api.contact.ContactId;
 import org.briarproject.bramble.api.contact.ContactManager;
+import org.briarproject.bramble.api.crypto.CryptoExecutor;
+import org.briarproject.bramble.api.db.DatabaseComponent;
 import org.briarproject.bramble.api.db.DatabaseExecutor;
 import org.briarproject.bramble.api.db.DbException;
 import org.briarproject.bramble.api.db.NoSuchContactException;
 import org.briarproject.bramble.api.identity.AuthorId;
 import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
+import org.briarproject.bramble.api.settings.Settings;
+import org.briarproject.bramble.api.settings.SettingsManager;
+import org.briarproject.bramble.api.sync.GroupId;
+import org.briarproject.bramble.api.sync.Message;
+import org.briarproject.bramble.api.sync.MessageId;
 import org.briarproject.briar.android.util.UiUtils;
+import org.briarproject.briar.api.messaging.Attachment;
+import org.briarproject.briar.api.messaging.AttachmentHeader;
 import org.briarproject.briar.api.messaging.MessagingManager;
+import org.briarproject.briar.api.messaging.PrivateMessage;
+import org.briarproject.briar.api.messaging.PrivateMessageFactory;
+import org.briarproject.briar.api.messaging.PrivateMessageHeader;
 
+import java.io.IOException;
+import java.io.InputStream;
+import java.util.ArrayList;
+import java.util.Collection;
+import java.util.List;
 import java.util.concurrent.Executor;
 import java.util.logging.Logger;
 
@@ -26,19 +48,34 @@ import javax.inject.Inject;
 import static java.util.Objects.requireNonNull;
 import static java.util.logging.Level.WARNING;
 import static java.util.logging.Logger.getLogger;
+import static org.briarproject.bramble.util.IoUtils.tryToClose;
 import static org.briarproject.bramble.util.LogUtils.logDuration;
 import static org.briarproject.bramble.util.LogUtils.logException;
 import static org.briarproject.bramble.util.LogUtils.now;
+import static org.briarproject.briar.android.conversation.AttachmentDimensions.getAttachmentDimensions;
+import static org.briarproject.briar.android.settings.SettingsFragment.SETTINGS_NAMESPACE;
+import static org.briarproject.briar.android.util.UiUtils.observeForeverOnce;
 
 @NotNullByDefault
 public class ConversationViewModel extends AndroidViewModel {
 
 	private static Logger LOG =
 			getLogger(ConversationViewModel.class.getName());
+	private static final String SHOW_ONBOARDING_IMAGE =
+			"showOnboardingImage";
+	private static final String SHOW_ONBOARDING_INTRODUCTION =
+			"showOnboardingIntroduction";
 
 	@DatabaseExecutor
 	private final Executor dbExecutor;
+	@CryptoExecutor
+	private final Executor cryptoExecutor;
+	// TODO replace with TransactionManager once it exists
+	private final DatabaseComponent db;
+	private final MessagingManager messagingManager;
 	private final ContactManager contactManager;
+	private final SettingsManager settingsManager;
+	private final PrivateMessageFactory privateMessageFactory;
 	private final AttachmentController attachmentController;
 
 	@Nullable
@@ -48,38 +85,64 @@ public class ConversationViewModel extends AndroidViewModel {
 			Transformations.map(contact, c -> c.getAuthor().getId());
 	private final LiveData<String> contactName =
 			Transformations.map(contact, UiUtils::getContactDisplayName);
+	private final MutableLiveData<Boolean> imageSupport =
+			new MutableLiveData<>();
+	private final MutableLiveData<Boolean> showImageOnboarding =
+			new MutableLiveData<>();
+	private final MutableLiveData<Boolean> showIntroductionOnboarding =
+			new MutableLiveData<>();
+	private final MutableLiveData<Boolean> showIntroductionAction =
+			new MutableLiveData<>();
 	private final MutableLiveData<Boolean> contactDeleted =
 			new MutableLiveData<>();
+	private final MutableLiveData<GroupId> messagingGroupId =
+			new MutableLiveData<>();
+	private final MutableLiveData<PrivateMessageHeader> addedHeader =
+			new MutableLiveData<>();
 
 	@Inject
 	ConversationViewModel(Application application,
 			@DatabaseExecutor Executor dbExecutor,
-			ContactManager contactManager, MessagingManager messagingManager) {
+			@CryptoExecutor Executor cryptoExecutor, DatabaseComponent db,
+			MessagingManager messagingManager, ContactManager contactManager,
+			SettingsManager settingsManager,
+			PrivateMessageFactory privateMessageFactory) {
 		super(application);
 		this.dbExecutor = dbExecutor;
+		this.cryptoExecutor = cryptoExecutor;
+		this.db = db;
+		this.messagingManager = messagingManager;
 		this.contactManager = contactManager;
+		this.settingsManager = settingsManager;
+		this.privateMessageFactory = privateMessageFactory;
 		this.attachmentController = new AttachmentController(messagingManager,
-				application.getResources());
+				getAttachmentDimensions(application.getResources()));
 		contactDeleted.setValue(false);
 	}
 
+	/**
+	 * Setting the {@link ContactId} automatically triggers loading of other
+	 * data.
+	 */
 	void setContactId(ContactId contactId) {
 		if (this.contactId == null) {
 			this.contactId = contactId;
-			loadContact();
+			loadContact(contactId);
 		} else if (!contactId.equals(this.contactId)) {
 			throw new IllegalStateException();
 		}
 	}
 
-	private void loadContact() {
+	private void loadContact(ContactId contactId) {
 		dbExecutor.execute(() -> {
 			try {
 				long start = now();
-				Contact c =
-						contactManager.getContact(requireNonNull(contactId));
+				Contact c = contactManager.getContact(contactId);
 				contact.postValue(c);
 				logDuration(LOG, "Loading contact", start);
+				start = now();
+				checkFeaturesAndOnboarding(contactId);
+				logDuration(LOG, "Checking for image support", start);
 			} catch (NoSuchContactException e) {
 				contactDeleted.postValue(true);
 			} catch (DbException e) {
@@ -88,18 +151,196 @@ public class ConversationViewModel extends AndroidViewModel {
 		});
 	}
 
+	void markMessageRead(GroupId g, MessageId m) {
+		dbExecutor.execute(() -> {
+			try {
+				long start = now();
+				messagingManager.setReadFlag(g, m, true);
+				logDuration(LOG, "Marking read", start);
+			} catch (DbException e) {
+				logException(LOG, WARNING, e);
+			}
+		});
+	}
+
 	void setContactAlias(String alias) {
 		dbExecutor.execute(() -> {
 			try {
 				contactManager.setContactAlias(requireNonNull(contactId),
 						alias.isEmpty() ? null : alias);
-				loadContact();
+				loadContact(contactId);
 			} catch (DbException e) {
 				logException(LOG, WARNING, e);
 			}
 		});
 	}
 
+	void sendMessage(@Nullable String text, List<Uri> uris, long timestamp) {
+		if (messagingGroupId.getValue() == null) loadGroupId();
+		observeForeverOnce(messagingGroupId, groupId -> {
+			if (groupId == null) return;
+			// calls through to creating and storing the message
+			storeAttachments(groupId, text, uris, timestamp);
+		});
+	}
+
+	private void loadGroupId() {
+		if (contactId == null) throw new IllegalStateException();
+		dbExecutor.execute(() -> {
+			try {
+				messagingGroupId.postValue(
+						messagingManager.getConversationId(contactId));
+			} catch (DbException e) {
+				logException(LOG, WARNING, e);
+			}
+		});
+	}
+
+	@DatabaseExecutor
+	private void checkFeaturesAndOnboarding(ContactId c) throws DbException {
+		// check if images are supported
+		boolean imagesSupported = db.transactionWithResult(true, txn ->
+				messagingManager.contactSupportsImages(txn, c));
+		imageSupport.postValue(imagesSupported);
+
+		// check if introductions are supported
+		Collection<Contact> contacts = contactManager.getActiveContacts();
+		boolean introductionSupported = contacts.size() > 1;
+		showIntroductionAction.postValue(introductionSupported);
+
+		Settings settings = settingsManager.getSettings(SETTINGS_NAMESPACE);
+		if (imagesSupported &&
+				settings.getBoolean(SHOW_ONBOARDING_IMAGE, true)) {
+			// check if we should show onboarding, only if images are supported
+			showImageOnboarding.postValue(true);
+			// allow observer to stop listening for changes
+			showIntroductionOnboarding.postValue(false);
+		} else {
+			// allow observer to stop listening for changes
+			showImageOnboarding.postValue(false);
+			// we only show one onboarding dialog at a time
+			if (introductionSupported &&
+					settings.getBoolean(SHOW_ONBOARDING_INTRODUCTION, true)) {
+				showIntroductionOnboarding.postValue(true);
+			} else {
+				// allow observer to stop listening for changes
+				showIntroductionOnboarding.postValue(false);
+			}
+		}
+	}
+
+	void onImageOnboardingSeen() {
+		onOnboardingSeen(SHOW_ONBOARDING_IMAGE);
+	}
+
+	void onIntroductionOnboardingSeen() {
+		onOnboardingSeen(SHOW_ONBOARDING_INTRODUCTION);
+	}
+
+	private void onOnboardingSeen(String key) {
+		dbExecutor.execute(() -> {
+			try {
+				Settings settings = new Settings();
+				settings.putBoolean(key, false);
+				settingsManager.mergeSettings(settings, SETTINGS_NAMESPACE);
+			} catch (DbException e) {
+				logException(LOG, WARNING, e);
+			}
+		});
+	}
+
+	private void storeAttachments(GroupId groupId, @Nullable String text,
+			List<Uri> uris, long timestamp) {
+		dbExecutor.execute(() -> {
+			long start = now();
+			List<AttachmentHeader> attachments = new ArrayList<>();
+			List<AttachmentItem> items = new ArrayList<>();
+			boolean needsSize = uris.size() == 1;
+			for (Uri uri : uris) {
+				Pair<AttachmentHeader, AttachmentItem> pair =
+						createAttachmentHeader(groupId, uri, timestamp,
+								needsSize);
+				if (pair == null) continue;
+				attachments.add(pair.getFirst());
+				items.add(pair.getSecond());
+			}
+			logDuration(LOG, "Storing attachments", start);
+			createMessage(groupId, text, attachments, items, timestamp);
+		});
+	}
+
+	@Nullable
+	@DatabaseExecutor
+	private Pair<AttachmentHeader, AttachmentItem> createAttachmentHeader(
+			GroupId groupId, Uri uri, long timestamp, boolean needsSize) {
+		InputStream is = null;
+		try {
+			ContentResolver contentResolver =
+					getApplication().getContentResolver();
+			is = contentResolver.openInputStream(uri);
+			if (is == null) throw new IOException();
+			String contentType = contentResolver.getType(uri);
+			if (contentType == null) throw new IOException("null content type");
+			AttachmentHeader h = messagingManager
+					.addLocalAttachment(groupId, timestamp, contentType, is);
+			is.close();
+			// re-open stream to get AttachmentItem
+			is = contentResolver.openInputStream(uri);
+			if (is == null) throw new IOException();
+			AttachmentItem item = attachmentController
+					.getAttachmentItem(h, new Attachment(is), needsSize);
+			return new Pair<>(h, item);
+		} catch (DbException | IOException e) {
+			logException(LOG, WARNING, e);
+			return null;
+		} finally {
+			if (is != null) tryToClose(is, LOG, WARNING);
+		}
+	}
+
+	private void createMessage(GroupId groupId, @Nullable String text,
+			List<AttachmentHeader> attachments, List<AttachmentItem> aItems,
+			long timestamp) {
+		cryptoExecutor.execute(() -> {
+			try {
+				// TODO remove when text can be null in the backend
+				String msgText = text == null ? "null" : text;
+				PrivateMessage pm = privateMessageFactory
+						.createPrivateMessage(groupId, timestamp, msgText,
+								attachments);
+				attachmentController.put(pm.getMessage().getId(), aItems);
+				storeMessage(pm, msgText, attachments);
+			} catch (FormatException e) {
+				throw new RuntimeException(e);
+			}
+		});
+	}
+
+	private void storeMessage(PrivateMessage m, @Nullable String text,
+			List<AttachmentHeader> attachments) {
+		dbExecutor.execute(() -> {
+			try {
+				long start = now();
+				messagingManager.addLocalMessage(m);
+				logDuration(LOG, "Storing message", start);
+				Message message = m.getMessage();
+				PrivateMessageHeader h = new PrivateMessageHeader(
+						message.getId(), message.getGroupId(),
+						message.getTimestamp(), true, true, false, false,
+						text != null, attachments);
+				// TODO add text to cache when available here
+				addedHeader.postValue(h);
+			} catch (DbException e) {
+				logException(LOG, WARNING, e);
+			}
+		});
+	}
+
+	@UiThread
+	void onAddedPrivateMessageSeen() {
+		addedHeader.setValue(null);
+	}
+
 	AttachmentController getAttachmentController() {
 		return attachmentController;
 	}
@@ -116,8 +357,28 @@ public class ConversationViewModel extends AndroidViewModel {
 		return contactName;
 	}
 
+	LiveData<Boolean> hasImageSupport() {
+		return imageSupport;
+	}
+
+	LiveData<Boolean> showImageOnboarding() {
+		return showImageOnboarding;
+	}
+
+	LiveData<Boolean> showIntroductionOnboarding() {
+		return showIntroductionOnboarding;
+	}
+
+	LiveData<Boolean> showIntroductionAction() {
+		return showIntroductionAction;
+	}
+
 	LiveData<Boolean> isContactDeleted() {
 		return contactDeleted;
 	}
 
+	LiveData<PrivateMessageHeader> getAddedPrivateMessage() {
+		return addedHeader;
+	}
+
 }

briar-android/src/main/java/org/briarproject/briar/android/conversation/ImageActivity.java

@@ -1,54 +1,84 @@
 package org.briarproject.briar.android.conversation;
 
-import android.graphics.drawable.Animatable;
+import android.arch.lifecycle.ViewModelProvider;
+import android.arch.lifecycle.ViewModelProviders;
+import android.content.DialogInterface.OnClickListener;
+import android.content.Intent;
 import android.graphics.drawable.Drawable;
 import android.os.Bundle;
 import android.support.annotation.Nullable;
 import android.support.annotation.RequiresApi;
 import android.support.design.widget.AppBarLayout;
+import android.support.design.widget.Snackbar;
+import android.support.v4.app.Fragment;
+import android.support.v4.app.FragmentManager;
+import android.support.v4.app.FragmentStatePagerAdapter;
+import android.support.v4.content.ContextCompat;
+import android.support.v4.graphics.drawable.DrawableCompat;
+import android.support.v4.view.ViewPager;
+import android.support.v7.app.AlertDialog.Builder;
 import android.support.v7.widget.Toolbar;
 import android.transition.Fade;
 import android.transition.Transition;
+import android.view.Menu;
 import android.view.MenuItem;
 import android.view.View;
+import android.view.ViewTreeObserver.OnGlobalLayoutListener;
 import android.view.Window;
 import android.widget.TextView;
 
-import com.bumptech.glide.load.DataSource;
-import com.bumptech.glide.load.engine.GlideException;
-import com.bumptech.glide.request.RequestListener;
-import com.bumptech.glide.request.target.Target;
-import com.github.chrisbanes.photoview.PhotoView;
-
+import org.briarproject.bramble.api.nullsafety.MethodsNotNullByDefault;
+import org.briarproject.bramble.api.nullsafety.ParametersNotNullByDefault;
 import org.briarproject.briar.R;
 import org.briarproject.briar.android.activity.ActivityComponent;
 import org.briarproject.briar.android.activity.BriarActivity;
-import org.briarproject.briar.android.conversation.glide.GlideApp;
 import org.briarproject.briar.android.view.PullDownLayout;
 
+import java.text.SimpleDateFormat;
+import java.util.Date;
+import java.util.List;
+import java.util.Locale;
+
+import javax.inject.Inject;
+
+import static android.content.Intent.ACTION_CREATE_DOCUMENT;
+import static android.content.Intent.CATEGORY_OPENABLE;
+import static android.content.Intent.EXTRA_TITLE;
 import static android.graphics.Color.TRANSPARENT;
 import static android.os.Build.VERSION.SDK_INT;
+import static android.support.design.widget.Snackbar.LENGTH_LONG;
 import static android.view.View.GONE;
 import static android.view.View.SYSTEM_UI_FLAG_FULLSCREEN;
 import static android.view.View.SYSTEM_UI_FLAG_LAYOUT_FULLSCREEN;
 import static android.view.View.SYSTEM_UI_FLAG_LAYOUT_STABLE;
 import static android.view.View.VISIBLE;
 import static android.view.WindowManager.LayoutParams.FLAG_TRANSLUCENT_STATUS;
-import static android.widget.ImageView.ScaleType.FIT_START;
-import static com.bumptech.glide.load.engine.DiskCacheStrategy.NONE;
 import static java.util.Objects.requireNonNull;
+import static org.briarproject.briar.android.activity.RequestCodes.REQUEST_SAVE_ATTACHMENT;
 import static org.briarproject.briar.android.util.UiUtils.formatDateAbsolute;
 
+@MethodsNotNullByDefault
+@ParametersNotNullByDefault
 public class ImageActivity extends BriarActivity
-		implements PullDownLayout.Callback {
+		implements PullDownLayout.Callback, OnGlobalLayoutListener {
 
-	final static String ATTACHMENT = "attachment";
+	final static String ATTACHMENTS = "attachments";
+	final static String ATTACHMENT_POSITION = "position";
 	final static String NAME = "name";
 	final static String DATE = "date";
 
+	@RequiresApi(api = 16)
+	private final static int UI_FLAGS_DEFAULT =
+			SYSTEM_UI_FLAG_LAYOUT_STABLE | SYSTEM_UI_FLAG_LAYOUT_FULLSCREEN;
+
+	@Inject
+	ViewModelProvider.Factory viewModelFactory;
+
+	private ImageViewModel viewModel;
 	private PullDownLayout layout;
 	private AppBarLayout appBarLayout;
-	private PhotoView photoView;
+	private ViewPager viewPager;
+	private List<AttachmentItem> attachments;
 
 	@Override
 	public void injectActivity(ActivityComponent component) {
@@ -60,18 +90,23 @@ public class ImageActivity extends BriarActivity
 		super.onCreate(state);
 
 		// Transitions
-		supportPostponeEnterTransition();
+		if (state == null) supportPostponeEnterTransition();
 		Window window = getWindow();
 		if (SDK_INT >= 21) {
 			Transition transition = new Fade();
 			setSceneTransitionAnimation(transition, null, transition);
 		}
 
+		// get View Model
+		viewModel = ViewModelProviders.of(this, viewModelFactory)
+				.get(ImageViewModel.class);
+		viewModel.getSaveState().observe(this, this::onImageSaveStateChanged);
+
 		// inflate layout
 		setContentView(R.layout.activity_image);
 		layout = findViewById(R.id.layout);
-		layout.getBackground().setAlpha(255);
 		layout.setCallback(this);
+		layout.getViewTreeObserver().addOnGlobalLayoutListener(this);
 
 		// Status Bar
 		if (SDK_INT >= 21) {
@@ -88,59 +123,33 @@ public class ImageActivity extends BriarActivity
 		TextView dateView = toolbar.findViewById(R.id.dateView);
 
 		// Intent Extras
-		AttachmentItem attachment = getIntent().getParcelableExtra(ATTACHMENT);
-		String name = getIntent().getStringExtra(NAME);
-		long time = getIntent().getLongExtra(DATE, 0);
+		Intent i = getIntent();
+		attachments = i.getParcelableArrayListExtra(ATTACHMENTS);
+		int position = i.getIntExtra(ATTACHMENT_POSITION, -1);
+		if (position == -1) throw new IllegalStateException();
+		String name = i.getStringExtra(NAME);
+		long time = i.getLongExtra(DATE, 0);
 		String date = formatDateAbsolute(this, time);
 		contactName.setText(name);
 		dateView.setText(date);
 
-		// Image View
-		photoView = findViewById(R.id.photoView);
+		// Set up image ViewPager
+		viewPager = findViewById(R.id.viewPager);
+		ImagePagerAdapter pagerAdapter =
+				new ImagePagerAdapter(getSupportFragmentManager());
+		viewPager.setAdapter(pagerAdapter);
+		viewPager.setCurrentItem(position);
+
 		if (SDK_INT >= 16) {
-			photoView.setOnClickListener(view -> toggleSystemUi());
-			window.getDecorView().setSystemUiVisibility(
-					SYSTEM_UI_FLAG_LAYOUT_STABLE |
-							SYSTEM_UI_FLAG_LAYOUT_FULLSCREEN);
+			viewModel.getOnImageClicked().observe(this, this::onImageClicked);
+			window.getDecorView().setSystemUiVisibility(UI_FLAGS_DEFAULT);
 		}
+	}
 
-		// Request Listener
-		RequestListener<Drawable> listener = new RequestListener<Drawable>() {
-			@Override
-			public boolean onLoadFailed(@Nullable GlideException e,
-					Object model, Target<Drawable> target,
-					boolean isFirstResource) {
-				supportStartPostponedEnterTransition();
-				return false;
-			}
-
-			@Override
-			public boolean onResourceReady(Drawable resource, Object model,
-					Target<Drawable> target, DataSource dataSource,
-					boolean isFirstResource) {
-				if (SDK_INT >= 21 && !(resource instanceof Animatable)) {
-					// set transition name only when not animatable,
-					// because the animation won't start otherwise
-					photoView.setTransitionName(
-							attachment.getTransitionName());
-				}
-				// Move image to the top if overlapping toolbar
-				if (isOverlappingToolbar(resource)) {
-					photoView.setScaleType(FIT_START);
-				}
-				supportStartPostponedEnterTransition();
-				return false;
-			}
-		};
-
-		// Load Image
-		GlideApp.with(this)
-				.load(attachment)
-				.diskCacheStrategy(NONE)
-				.error(R.drawable.ic_image_broken)
-				.dontTransform()
-				.addListener(listener)
-				.into(photoView);
+	@Override
+	public boolean onCreateOptionsMenu(Menu menu) {
+		getMenuInflater().inflate(R.menu.image_actions, menu);
+		return super.onCreateOptionsMenu(menu);
 	}
 
 	@Override
@@ -149,11 +158,36 @@ public class ImageActivity extends BriarActivity
 			case android.R.id.home:
 				onBackPressed();
 				return true;
+			case R.id.action_save_image:
+				showSaveImageDialog();
+				return true;
 			default:
 				return super.onOptionsItemSelected(item);
 		}
 	}
 
+	@Override
+	public void onGlobalLayout() {
+		viewModel.setToolbarPosition(
+				appBarLayout.getTop(), appBarLayout.getBottom()
+		);
+		if (SDK_INT >= 16) {
+			layout.getViewTreeObserver().removeOnGlobalLayoutListener(this);
+		} else {
+			layout.getViewTreeObserver().removeGlobalOnLayoutListener(this);
+		}
+	}
+
+	@Override
+	protected void onActivityResult(int request, int result,
+			@Nullable Intent data) {
+		super.onActivityResult(request, result, data);
+		if (request == REQUEST_SAVE_ATTACHMENT && result == RESULT_OK &&
+				data != null) {
+			viewModel.saveImage(getVisibleAttachment(), data.getData());
+		}
+	}
+
 	@Override
 	public void onPullStart() {
 		appBarLayout.animate()
@@ -163,7 +197,6 @@ public class ImageActivity extends BriarActivity
 
 	@Override
 	public void onPull(float progress) {
-		layout.getBackground().setAlpha(Math.round((1 - progress) * 255));
 	}
 
 	@Override
@@ -175,9 +208,24 @@ public class ImageActivity extends BriarActivity
 
 	@Override
 	public void onPullComplete() {
+		showStatusBarBeforeFinishing();
 		supportFinishAfterTransition();
 	}
 
+	@Override
+	public void onBackPressed() {
+		showStatusBarBeforeFinishing();
+		super.onBackPressed();
+	}
+
+	@RequiresApi(api = 16)
+	private void onImageClicked(@Nullable Boolean clicked) {
+		if (clicked != null && clicked) {
+			toggleSystemUi();
+			viewModel.onOnImageClickSeen();
+		}
+	}
+
 	@RequiresApi(api = 16)
 	private void toggleSystemUi() {
 		View decorView = getWindow().getDecorView();
@@ -190,10 +238,8 @@ public class ImageActivity extends BriarActivity
 
 	@RequiresApi(api = 16)
 	private void hideSystemUi(View decorView) {
-		decorView.setSystemUiVisibility(SYSTEM_UI_FLAG_LAYOUT_STABLE
-				| SYSTEM_UI_FLAG_LAYOUT_FULLSCREEN
-				| SYSTEM_UI_FLAG_FULLSCREEN
-		);
+		decorView.setSystemUiVisibility(
+				SYSTEM_UI_FLAG_FULLSCREEN | UI_FLAGS_DEFAULT);
 		appBarLayout.animate()
 				.translationYBy(-1 * appBarLayout.getHeight())
 				.alpha(0f)
@@ -203,10 +249,7 @@ public class ImageActivity extends BriarActivity
 
 	@RequiresApi(api = 16)
 	private void showSystemUi(View decorView) {
-		decorView.setSystemUiVisibility(
-				SYSTEM_UI_FLAG_LAYOUT_STABLE
-						| SYSTEM_UI_FLAG_LAYOUT_FULLSCREEN
-		);
+		decorView.setSystemUiVisibility(UI_FLAGS_DEFAULT);
 		appBarLayout.animate()
 				.translationYBy(appBarLayout.getHeight())
 				.alpha(1f)
@@ -214,20 +257,88 @@ public class ImageActivity extends BriarActivity
 				.start();
 	}
 
-	private boolean isOverlappingToolbar(Drawable drawable) {
-		int width = drawable.getIntrinsicWidth();
-		int height = drawable.getIntrinsicHeight();
-		float widthPercentage = photoView.getWidth() / (float) width;
-		float heightPercentage = photoView.getHeight() / (float) height;
-		float scaleFactor = Math.min(widthPercentage, heightPercentage);
-		int realWidth = (int) (width * scaleFactor);
-		int realHeight = (int) (height * scaleFactor);
-		// return if photo doesn't use the full width,
-		// because it will be moved to the right otherwise
-		if (realWidth < photoView.getWidth()) return false;
-		int drawableTop = (photoView.getHeight() - realHeight) / 2;
-		return drawableTop < appBarLayout.getBottom() &&
-				drawableTop != appBarLayout.getTop();
+	/**
+	 * If we don't show the status bar again before finishing this activity,
+	 * the return transition will "jump" down the size of the status bar
+	 * when the previous activity (with visible status bar) is shown.
+	 */
+	private void showStatusBarBeforeFinishing() {
+		if (SDK_INT >= 16 && appBarLayout.getVisibility() == GONE) {
+			View decorView = getWindow().getDecorView();
+			decorView.setSystemUiVisibility(UI_FLAGS_DEFAULT);
+		}
+	}
+
+	private void showSaveImageDialog() {
+		OnClickListener okListener = (dialog, which) -> {
+			if (SDK_INT >= 19) {
+				Intent intent = getCreationIntent();
+				startActivityForResult(intent, REQUEST_SAVE_ATTACHMENT);
+			} else {
+				viewModel.saveImage(getVisibleAttachment());
+			}
+		};
+		Builder builder = new Builder(this, R.style.BriarDialogTheme);
+		builder.setTitle(getString(R.string.dialog_title_save_image));
+		builder.setMessage(getString(R.string.dialog_message_save_image));
+		Drawable icon = ContextCompat.getDrawable(this, R.drawable.ic_security);
+		DrawableCompat.setTint(requireNonNull(icon),
+				ContextCompat.getColor(this, R.color.color_primary));
+		builder.setIcon(icon);
+		builder.setPositiveButton(R.string.save_image, okListener);
+		builder.setNegativeButton(R.string.cancel, null);
+		builder.show();
+	}
+
+	@RequiresApi(api = 19)
+	private Intent getCreationIntent() {
+		SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd'T'HH:mm:ss",
+				Locale.getDefault());
+		String fileName = sdf.format(new Date());
+		Intent intent = new Intent(ACTION_CREATE_DOCUMENT);
+		intent.addCategory(CATEGORY_OPENABLE);
+		intent.setType(getVisibleAttachment().getMimeType());
+		intent.putExtra(EXTRA_TITLE, fileName);
+		return intent;
+	}
+
+	private void onImageSaveStateChanged(@Nullable Boolean error) {
+		if (error == null) return;
+		int stringRes = error ?
+				R.string.save_image_error : R.string.save_image_success;
+		int colorRes = error ?
+				R.color.briar_red : R.color.briar_primary;
+		Snackbar s = Snackbar.make(layout, stringRes, LENGTH_LONG);
+		s.getView().setBackgroundResource(colorRes);
+		s.show();
+		viewModel.onSaveStateSeen();
+	}
+
+	AttachmentItem getVisibleAttachment() {
+		return attachments.get(viewPager.getCurrentItem());
+	}
+
+	private class ImagePagerAdapter extends FragmentStatePagerAdapter {
+
+		private boolean isFirst = true;
+
+		private ImagePagerAdapter(FragmentManager fm) {
+			super(fm);
+		}
+
+		@Override
+		public Fragment getItem(int position) {
+			Fragment f = ImageFragment
+					.newInstance(attachments.get(position), isFirst);
+			isFirst = false;
+			return f;
+		}
+
+		@Override
+		public int getCount() {
+			return attachments.size();
+		}
+
 	}
 
 }

briar-android/src/main/java/org/briarproject/briar/android/conversation/ImageAdapter.java

@@ -0,0 +1,155 @@
+package org.briarproject.briar.android.conversation;
+
+import android.content.Context;
+import android.content.res.Resources;
+import android.support.annotation.Nullable;
+import android.support.v7.widget.RecyclerView.Adapter;
+import android.util.DisplayMetrics;
+import android.view.LayoutInflater;
+import android.view.View;
+import android.view.ViewGroup;
+import android.view.WindowManager;
+
+import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
+import org.briarproject.briar.R;
+import org.briarproject.briar.android.conversation.glide.Radii;
+
+import java.util.ArrayList;
+import java.util.List;
+
+import static android.content.Context.WINDOW_SERVICE;
+import static java.util.Objects.requireNonNull;
+import static org.briarproject.briar.android.util.UiUtils.isRtl;
+
+@NotNullByDefault
+class ImageAdapter extends Adapter<ImageViewHolder> {
+
+	private final List<AttachmentItem> items = new ArrayList<>();
+	private final ConversationListener listener;
+	private final int imageSize;
+	private final int radiusBig, radiusSmall;
+	private final boolean isRtl;
+	@Nullable
+	private ConversationMessageItem conversationItem;
+
+	ImageAdapter(Context ctx, ConversationListener listener) {
+		this.listener = listener;
+		imageSize = getImageSize(ctx);
+		Resources res = ctx.getResources();
+		radiusBig =
+				res.getDimensionPixelSize(R.dimen.message_bubble_radius_big);
+		radiusSmall =
+				res.getDimensionPixelSize(R.dimen.message_bubble_radius_small);
+		isRtl = isRtl(ctx);
+	}
+
+	@Override
+	public ImageViewHolder onCreateViewHolder(ViewGroup viewGroup, int type) {
+		View v = LayoutInflater.from(viewGroup.getContext()).inflate(
+				R.layout.list_item_image, viewGroup, false);
+		return new ImageViewHolder(v, imageSize);
+	}
+
+	@Override
+	public void onBindViewHolder(ImageViewHolder imageViewHolder,
+			int position) {
+		// get item
+		requireNonNull(conversationItem);
+		AttachmentItem item = items.get(position);
+		// set onClick listener
+		imageViewHolder.itemView.setOnClickListener(v ->
+				listener.onAttachmentClicked(v, conversationItem, item)
+		);
+		// bind view holder
+		int size = items.size();
+		boolean isIncoming = conversationItem.isIncoming();
+		boolean hasText = conversationItem.getText() != null;
+		Radii r = getRadii(position, size, isIncoming, hasText);
+		imageViewHolder.bind(item, r, size == 1, singleInRow(position, size));
+	}
+
+	@Override
+	public int getItemCount() {
+		return items.size();
+	}
+
+	void setConversationItem(ConversationMessageItem item) {
+		this.conversationItem = item;
+		this.items.clear();
+		this.items.addAll(item.getAttachments());
+		notifyDataSetChanged();
+	}
+
+	private int getImageSize(Context ctx) {
+		Resources res = ctx.getResources();
+		WindowManager windowManager =
+				(WindowManager) ctx.getSystemService(WINDOW_SERVICE);
+		DisplayMetrics displayMetrics = new DisplayMetrics();
+		if (windowManager == null) {
+			return res.getDimensionPixelSize(
+					R.dimen.message_bubble_image_default);
+		}
+		windowManager.getDefaultDisplay().getMetrics(displayMetrics);
+		int imageSize = displayMetrics.widthPixels / 3;
+		int maxSize = res.getDimensionPixelSize(
+				R.dimen.message_bubble_image_max_width);
+		return Math.min(imageSize, maxSize);
+	}
+
+	private Radii getRadii(int pos, int num, boolean isIncoming,
+			boolean hasText) {
+		boolean left = isLeft(pos);
+		boolean single = num == 1;
+		// Top Row
+		int topLeft;
+		int topRight;
+		if (single) {
+			topLeft = isIncoming ? radiusSmall : radiusBig;
+			topRight = !isIncoming ? radiusSmall : radiusBig;
+		} else if (isTopRow(pos)) {
+			topLeft = left ? (isIncoming ? radiusSmall : radiusBig) : 0;
+			topRight = !left ? (!isIncoming ? radiusSmall : radiusBig) : 0;
+		} else {
+			topLeft = 0;
+			topRight = 0;
+		}
+		// Bottom Row
+		boolean singleInRow = singleInRow(pos, num);
+		int bottomLeft;
+		int bottomRight;
+		if (!hasText && isBottomRow(pos, num)) {
+			bottomLeft = singleInRow || left ? radiusBig : 0;
+			bottomRight = singleInRow || !left ? radiusBig : 0;
+		} else {
+			bottomLeft = 0;
+			bottomRight = 0;
+		}
+		if (isRtl) return new Radii(topRight, topLeft, bottomRight, bottomLeft);
+		return new Radii(topLeft, topRight, bottomLeft, bottomRight);
+	}
+
+	void clear() {
+		items.clear();
+		notifyDataSetChanged();
+	}
+
+	static boolean isTopRow(int pos) {
+		return pos < 2;
+	}
+
+	static boolean isLeft(int pos) {
+		return pos % 2 == 0;
+	}
+
+	static boolean isBottomRow(int pos, int num) {
+		return num % 2 == 0 ?
+				pos >= num - 2 : // last two, if even
+				pos > num - 2;   // last one, if odd
+	}
+
+	static boolean singleInRow(int pos, int num) {
+		// last item of an odd number
+		return num % 2 != 0 && pos == num -1;
+	}
+
+}

briar-android/src/main/java/org/briarproject/briar/android/conversation/ImageFragment.java

@@ -0,0 +1,133 @@
+package org.briarproject.briar.android.conversation;
+
+import android.arch.lifecycle.ViewModelProvider;
+import android.arch.lifecycle.ViewModelProviders;
+import android.graphics.drawable.Animatable;
+import android.graphics.drawable.Drawable;
+import android.os.Bundle;
+import android.support.annotation.Nullable;
+import android.support.v4.app.Fragment;
+import android.view.LayoutInflater;
+import android.view.View;
+import android.view.ViewGroup;
+
+import com.bumptech.glide.load.DataSource;
+import com.bumptech.glide.load.engine.GlideException;
+import com.bumptech.glide.request.RequestListener;
+import com.bumptech.glide.request.target.Target;
+import com.github.chrisbanes.photoview.PhotoView;
+
+import org.briarproject.bramble.api.nullsafety.MethodsNotNullByDefault;
+import org.briarproject.briar.R;
+import org.briarproject.briar.android.activity.BaseActivity;
+import org.briarproject.briar.android.conversation.glide.GlideApp;
+
+import javax.annotation.ParametersAreNonnullByDefault;
+import javax.inject.Inject;
+
+import static android.os.Build.VERSION.SDK_INT;
+import static android.widget.ImageView.ScaleType.FIT_START;
+import static com.bumptech.glide.load.engine.DiskCacheStrategy.NONE;
+import static org.briarproject.bramble.api.nullsafety.NullSafety.requireNonNull;
+import static org.briarproject.briar.android.conversation.ImageActivity.ATTACHMENT_POSITION;
+
+@MethodsNotNullByDefault
+@ParametersAreNonnullByDefault
+public class ImageFragment extends Fragment {
+
+	private final static String IS_FIRST = "isFirst";
+
+	@Inject
+	ViewModelProvider.Factory viewModelFactory;
+
+	private AttachmentItem attachment;
+	private boolean isFirst;
+	private ImageViewModel viewModel;
+	private PhotoView photoView;
+
+	static ImageFragment newInstance(AttachmentItem a, boolean isFirst) {
+		ImageFragment f = new ImageFragment();
+		Bundle args = new Bundle();
+		args.putParcelable(ATTACHMENT_POSITION, a);
+		args.putBoolean(IS_FIRST, isFirst);
+		f.setArguments(args);
+		return f;
+	}
+
+	@Override
+	public void onActivityCreated(@Nullable Bundle savedInstanceState) {
+		super.onActivityCreated(savedInstanceState);
+		BaseActivity a = (BaseActivity) requireNonNull(getActivity());
+		a.getActivityComponent().inject(this);
+	}
+
+	@Override
+	public void onCreate(@Nullable Bundle savedInstanceState) {
+		super.onCreate(savedInstanceState);
+
+		Bundle args = requireNonNull(getArguments());
+		attachment = requireNonNull(args.getParcelable(ATTACHMENT_POSITION));
+		isFirst = args.getBoolean(IS_FIRST);
+	}
+
+	@Nullable
+	@Override
+	public View onCreateView(LayoutInflater inflater,
+			@Nullable ViewGroup container,
+			@Nullable Bundle savedInstanceState) {
+		View v = inflater.inflate(R.layout.fragment_image, container,
+				false);
+
+		viewModel = ViewModelProviders.of(requireNonNull(getActivity()),
+				viewModelFactory).get(ImageViewModel.class);
+
+		photoView = v.findViewById(R.id.photoView);
+		photoView.setScaleLevels(1, 2, 4);
+		photoView.setOnClickListener(view -> viewModel.clickImage());
+
+		// Request Listener
+		RequestListener<Drawable> listener = new RequestListener<Drawable>() {
+			@Override
+			public boolean onLoadFailed(@Nullable GlideException e,
+					Object model, Target<Drawable> target,
+					boolean isFirstResource) {
+				if (getActivity() != null && isFirst)
+					getActivity().supportStartPostponedEnterTransition();
+				return false;
+			}
+
+			@Override
+			public boolean onResourceReady(Drawable resource, Object model,
+					Target<Drawable> target, DataSource dataSource,
+					boolean isFirstResource) {
+				if (SDK_INT >= 21 && !(resource instanceof Animatable)) {
+					// set transition name only when not animatable,
+					// because the animation won't start otherwise
+					photoView.setTransitionName(
+							attachment.getTransitionName());
+				}
+				// Move image to the top if overlapping toolbar
+				if (viewModel.isOverlappingToolbar(photoView, resource)) {
+					photoView.setScaleType(FIT_START);
+				}
+				if (getActivity() != null && isFirst) {
+					getActivity().supportStartPostponedEnterTransition();
+				}
+				return false;
+			}
+		};
+
+		// Load Image
+		GlideApp.with(this)
+				.load(attachment)
+				// TODO allow if size < maxTextureSize ?
+//				.override(SIZE_ORIGINAL)
+				.diskCacheStrategy(NONE)
+				.error(R.drawable.ic_image_broken)
+				.addListener(listener)
+				.into(photoView);
+
+		return v;
+	}
+
+}

briar-android/src/main/java/org/briarproject/briar/android/conversation/ImageHelper.java

@@ -0,0 +1,29 @@
+package org.briarproject.briar.android.conversation;
+
+import android.support.annotation.Nullable;
+
+import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
+
+import java.io.InputStream;
+
+@NotNullByDefault
+interface ImageHelper {
+
+	DecodeResult decodeStream(InputStream is);
+
+	@Nullable
+	String getExtensionFromMimeType(String mimeType);
+
+	class DecodeResult {
+
+		final int width;
+		final int height;
+		final String mimeType;
+
+		DecodeResult(int width, int height, String mimeType) {
+			this.width = width;
+			this.height = height;
+			this.mimeType = mimeType;
+		}
+	}
+}

briar-android/src/main/java/org/briarproject/briar/android/conversation/ImageItemDecoration.java

@@ -0,0 +1,54 @@
+package org.briarproject.briar.android.conversation;
+
+import android.content.Context;
+import android.content.res.Resources;
+import android.graphics.Rect;
+import android.support.v7.widget.RecyclerView;
+import android.support.v7.widget.RecyclerView.ItemDecoration;
+import android.support.v7.widget.RecyclerView.State;
+import android.view.View;
+
+import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
+import org.briarproject.briar.R;
+
+import static org.briarproject.briar.android.conversation.ImageAdapter.isBottomRow;
+import static org.briarproject.briar.android.conversation.ImageAdapter.isLeft;
+import static org.briarproject.briar.android.conversation.ImageAdapter.isTopRow;
+import static org.briarproject.briar.android.conversation.ImageAdapter.singleInRow;
+import static org.briarproject.briar.android.util.UiUtils.isRtl;
+
+@NotNullByDefault
+class ImageItemDecoration extends ItemDecoration {
+
+	private final int border;
+	private final boolean isRtl;
+
+	ImageItemDecoration(Context ctx) {
+		Resources res = ctx.getResources();
+
+		// for pixel perfection, add a pixel to the border if it has an odd size
+		int b = res.getDimensionPixelSize(R.dimen.message_bubble_border);
+		int realBorderSize = b % 2 == 0 ? b : b + 1;
+
+		// we are applying half the border around the insides of each image
+		// to prevent differently sized images looking slightly broken
+		border = realBorderSize / 2;
+
+		// find out if we are showing a RTL language
+		isRtl = isRtl(ctx);
+	}
+
+	@Override
+	public void getItemOffsets(Rect outRect, View view, RecyclerView parent,
+			State state) {
+		if (state.getItemCount() == 1) return;
+		int pos = parent.getChildAdapterPosition(view);
+		int num = state.getItemCount();
+		boolean start = isLeft(pos) ^ isRtl;
+		outRect.top = isTopRow(pos) ? 0 : border;
+		outRect.left = start ? 0 : border;
+		outRect.right = start && !singleInRow(pos, num) ? border : 0;
+		outRect.bottom = isBottomRow(pos, num) ? 0 : border;
+	}
+
+}

briar-android/src/main/java/org/briarproject/briar/android/conversation/ImageViewHolder.java

@@ -0,0 +1,74 @@
+package org.briarproject.briar.android.conversation;
+
+import android.graphics.Bitmap;
+import android.support.annotation.DrawableRes;
+import android.support.v7.widget.RecyclerView.ViewHolder;
+import android.support.v7.widget.StaggeredGridLayoutManager.LayoutParams;
+import android.view.View;
+import android.widget.ImageView;
+
+import com.bumptech.glide.load.Transformation;
+
+import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
+import org.briarproject.briar.R;
+import org.briarproject.briar.android.conversation.glide.BriarImageTransformation;
+import org.briarproject.briar.android.conversation.glide.GlideApp;
+import org.briarproject.briar.android.conversation.glide.Radii;
+
+import static android.os.Build.VERSION.SDK_INT;
+import static com.bumptech.glide.load.engine.DiskCacheStrategy.NONE;
+import static com.bumptech.glide.load.resource.drawable.DrawableTransitionOptions.withCrossFade;
+
+@NotNullByDefault
+class ImageViewHolder extends ViewHolder {
+
+	@DrawableRes
+	private static final int ERROR_RES = R.drawable.ic_image_broken;
+
+	protected final ImageView imageView;
+	private final int imageSize;
+
+	ImageViewHolder(View v, int imageSize) {
+		super(v);
+		imageView = v.findViewById(R.id.imageView);
+		this.imageSize = imageSize;
+	}
+
+	void bind(AttachmentItem attachment, Radii r, boolean single,
+			boolean needsStretch) {
+		if (attachment.hasError()) {
+			GlideApp.with(imageView)
+					.clear(imageView);
+			imageView.setImageResource(ERROR_RES);
+		} else {
+			setImageViewDimensions(attachment, single, needsStretch);
+			loadImage(attachment, r);
+			if (SDK_INT >= 21) {
+				imageView.setTransitionName(attachment.getTransitionName());
+			}
+		}
+	}
+
+	private void setImageViewDimensions(AttachmentItem a, boolean single,
+			boolean needsStretch) {
+		LayoutParams params = (LayoutParams) imageView.getLayoutParams();
+		int width = needsStretch ? imageSize * 2 : imageSize;
+		params.width = single ? a.getThumbnailWidth() : width;
+		params.height = single ? a.getThumbnailHeight() : imageSize;
+		params.setFullSpan(!single && needsStretch);
+		imageView.setLayoutParams(params);
+	}
+
+	private void loadImage(AttachmentItem a, Radii r) {
+		Transformation<Bitmap> transformation = new BriarImageTransformation(r);
+		GlideApp.with(imageView)
+				.load(a)
+				.diskCacheStrategy(NONE)
+				.error(ERROR_RES)
+				.transform(transformation)
+				.transition(withCrossFade())
+				.into(imageView)
+				.waitForLayout();
+	}
+
+}

briar-android/src/main/java/org/briarproject/briar/android/conversation/ImageViewModel.java

@@ -0,0 +1,214 @@
+package org.briarproject.briar.android.conversation;
+
+import android.app.Application;
+import android.arch.lifecycle.AndroidViewModel;
+import android.arch.lifecycle.LiveData;
+import android.arch.lifecycle.MutableLiveData;
+import android.graphics.drawable.Drawable;
+import android.net.Uri;
+import android.support.annotation.Nullable;
+import android.support.annotation.UiThread;
+import android.view.View;
+
+import org.briarproject.bramble.api.db.DatabaseExecutor;
+import org.briarproject.bramble.api.db.DbException;
+import org.briarproject.bramble.api.lifecycle.IoExecutor;
+import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
+import org.briarproject.bramble.api.sync.MessageId;
+import org.briarproject.briar.api.messaging.Attachment;
+import org.briarproject.briar.api.messaging.MessagingManager;
+
+import java.io.File;
+import java.io.FileOutputStream;
+import java.io.IOException;
+import java.io.InputStream;
+import java.io.OutputStream;
+import java.text.SimpleDateFormat;
+import java.util.Date;
+import java.util.Locale;
+import java.util.concurrent.Executor;
+import java.util.logging.Logger;
+
+import javax.inject.Inject;
+
+import static android.media.MediaScannerConnection.scanFile;
+import static android.os.Environment.DIRECTORY_PICTURES;
+import static android.os.Environment.getExternalStoragePublicDirectory;
+import static java.util.logging.Level.WARNING;
+import static java.util.logging.Logger.getLogger;
+import static org.briarproject.bramble.util.IoUtils.copyAndClose;
+import static org.briarproject.bramble.util.LogUtils.logException;
+
+@NotNullByDefault
+public class ImageViewModel extends AndroidViewModel {
+
+	private static Logger LOG = getLogger(ImageViewModel.class.getName());
+
+	private final MessagingManager messagingManager;
+	@DatabaseExecutor
+	private final Executor dbExecutor;
+	@IoExecutor
+	private final Executor ioExecutor;
+
+	/**
+	 * true means there was an error saving the image, false if image was saved.
+	 */
+	private final MutableLiveData<Boolean> saveState = new MutableLiveData<>();
+	private final MutableLiveData<Boolean> imageClicked =
+			new MutableLiveData<>();
+	private int toolbarTop, toolbarBottom;
+
+	@Inject
+	ImageViewModel(Application application,
+			MessagingManager messagingManager,
+			@DatabaseExecutor Executor dbExecutor,
+			@IoExecutor Executor ioExecutor) {
+		super(application);
+		this.messagingManager = messagingManager;
+		this.dbExecutor = dbExecutor;
+		this.ioExecutor = ioExecutor;
+	}
+
+	void clickImage() {
+		imageClicked.setValue(true);
+	}
+
+	/**
+	 * A LiveData that is true if the image was clicked,
+	 * false if it wasn't.
+	 *
+	 * Call {@link #onOnImageClickSeen()} after consuming an update.
+	 */
+	LiveData<Boolean> getOnImageClicked() {
+		return imageClicked;
+	}
+
+	@UiThread
+	void onOnImageClickSeen() {
+		imageClicked.setValue(false);
+	}
+
+	void setToolbarPosition(int top, int bottom) {
+		toolbarTop = top;
+		toolbarBottom = bottom;
+	}
+
+	boolean isOverlappingToolbar(View screenView, Drawable drawable) {
+		int width = drawable.getIntrinsicWidth();
+		int height = drawable.getIntrinsicHeight();
+		float widthPercentage = screenView.getWidth() / (float) width;
+		float heightPercentage = screenView.getHeight() / (float) height;
+		float scaleFactor = Math.min(widthPercentage, heightPercentage);
+		int realWidth = (int) (width * scaleFactor);
+		int realHeight = (int) (height * scaleFactor);
+		// return if image doesn't use the full width,
+		// because it will be moved to the right otherwise
+		if (realWidth < screenView.getWidth()) return false;
+		int drawableTop = (screenView.getHeight() - realHeight) / 2;
+		return drawableTop < toolbarBottom && drawableTop != toolbarTop;
+	}
+
+	/**
+	 * A LiveData that is true if there was an error
+	 * and false if the image was saved.
+	 * It can be null otherwise, if no image was saved recently.
+	 *
+	 * Call {@link #onSaveStateSeen()} after consuming an update.
+	 */
+	LiveData<Boolean> getSaveState() {
+		return saveState;
+	}
+
+	@UiThread
+	void onSaveStateSeen() {
+		saveState.setValue(null);
+	}
+
+	/**
+	 * Saves the attachment to a writeable {@link Uri}.
+	 */
+	@UiThread
+	void saveImage(AttachmentItem attachment, @Nullable Uri uri) {
+		if (uri == null) {
+			saveState.setValue(true);
+		} else {
+			saveImage(attachment, () -> getOutputStream(uri), null);
+		}
+	}
+
+	/**
+	 * Saves the attachment on external storage,
+	 * assuming the permission was granted during install time.
+	 */
+	void saveImage(AttachmentItem attachment) {
+		File file = getImageFile(attachment);
+		saveImage(attachment, () -> getOutputStream(file), () -> scanFile(
+				getApplication(), new String[] {file.toString()}, null, null));
+	}
+
+	private void saveImage(AttachmentItem attachment, OutputStreamProvider osp,
+			@Nullable Runnable afterCopy) {
+		MessageId messageId = attachment.getMessageId();
+		dbExecutor.execute(() -> {
+			try {
+				Attachment a = messagingManager.getAttachment(messageId);
+				copyImageFromDb(a, osp, afterCopy);
+			} catch (DbException e) {
+				logException(LOG, WARNING, e);
+				saveState.postValue(true);
+			}
+		});
+	}
+
+	private void copyImageFromDb(Attachment a, OutputStreamProvider osp,
+			@Nullable Runnable afterCopy) {
+		ioExecutor.execute(() -> {
+			try {
+				InputStream is = a.getStream();
+				OutputStream os = osp.getOutputStream();
+				copyAndClose(is, os);
+				if (afterCopy != null) afterCopy.run();
+				saveState.postValue(false);
+			} catch (IOException e) {
+				logException(LOG, WARNING, e);
+				saveState.postValue(true);
+			}
+		});
+	}
+
+	private String getFileName() {
+		SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd'T'HH:mm:ss",
+				Locale.getDefault());
+		return sdf.format(new Date());
+	}
+
+	private File getImageFile(AttachmentItem attachment) {
+		File path = getExternalStoragePublicDirectory(DIRECTORY_PICTURES);
+		//noinspection ResultOfMethodCallIgnored
+		path.mkdirs();
+		String fileName = getFileName();
+		String ext = "." + attachment.getExtension();
+		File file = new File(path, fileName + ext);
+		int i = 1;
+		while (file.exists()) {
+			file = new File(path, fileName + " (" + i + ")" + ext);
+		}
+		return file;
+	}
+
+	private OutputStream getOutputStream(File file) throws IOException {
+		return new FileOutputStream(file);
+	}
+
+	private OutputStream getOutputStream(Uri uri) throws IOException {
+		OutputStream os =
+				getApplication().getContentResolver().openOutputStream(uri);
+		if (os == null) throw new IOException();
+		return os;
+	}
+
+	private interface OutputStreamProvider {
+		OutputStream getOutputStream() throws IOException;
+	}
+
+}

briar-android/src/main/java/org/briarproject/briar/android/conversation/glide/BriarDataFetcher.java

@@ -40,7 +40,7 @@ class BriarDataFetcher implements DataFetcher<InputStream> {
 	private volatile boolean cancel = false;
 
 	@Inject
-	public BriarDataFetcher(MessagingManager messagingManager,
+	BriarDataFetcher(MessagingManager messagingManager,
 			@DatabaseExecutor Executor dbExecutor, AttachmentItem attachment) {
 		this.messagingManager = messagingManager;
 		this.dbExecutor = dbExecutor;

briar-android/src/main/java/org/briarproject/briar/android/conversation/glide/BriarImageTransformation.java

@@ -7,10 +7,8 @@ import com.bumptech.glide.load.resource.bitmap.CenterCrop;
 
 public class BriarImageTransformation extends MultiTransformation<Bitmap> {
 
-	public BriarImageTransformation(int smallRadius, int radius,
-			boolean leftCornerSmall, boolean bottomRound) {
-		super(new CenterCrop(), new ImageCornerTransformation(
-				smallRadius, radius, leftCornerSmall, bottomRound));
+	public BriarImageTransformation(Radii r) {
+		super(new CenterCrop(), new CustomCornersTransformation(r));
 	}
 
 }

briar-android/src/main/java/org/briarproject/briar/android/conversation/glide/BriarModelLoader.java

@@ -22,7 +22,7 @@ public final class BriarModelLoader
 	@Inject
 	BriarDataFetcherFactory dataFetcherFactory;
 
-	public BriarModelLoader(BriarApplication app) {
+	BriarModelLoader(BriarApplication app) {
 		app.getApplicationComponent().inject(this);
 	}
 

briar-android/src/main/java/org/briarproject/briar/android/conversation/glide/BriarModelLoaderFactory.java

@@ -16,7 +16,7 @@ class BriarModelLoaderFactory
 
 	private final BriarApplication app;
 
-	public BriarModelLoaderFactory(BriarApplication app) {
+	BriarModelLoaderFactory(BriarApplication app) {
 		this.app = app;
 	}
 

briar-android/src/main/java/org/briarproject/briar/android/conversation/glide/CustomCornersTransformation.java

@@ -0,0 +1,129 @@
+package org.briarproject.briar.android.conversation.glide;
+
+import android.graphics.Bitmap;
+import android.graphics.BitmapShader;
+import android.graphics.Canvas;
+import android.graphics.Paint;
+import android.graphics.RectF;
+import android.support.annotation.NonNull;
+
+import com.bumptech.glide.load.engine.bitmap_recycle.BitmapPool;
+import com.bumptech.glide.load.resource.bitmap.BitmapTransformation;
+
+import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
+
+import java.security.MessageDigest;
+
+import javax.annotation.concurrent.Immutable;
+
+import static android.graphics.Bitmap.Config.ARGB_8888;
+import static android.graphics.Shader.TileMode.CLAMP;
+
+@Immutable
+@NotNullByDefault
+class CustomCornersTransformation extends BitmapTransformation {
+
+	private static final String ID =
+			CustomCornersTransformation.class.getName();
+
+	private final Radii radii;
+
+	CustomCornersTransformation(Radii radii) {
+		this.radii = radii;
+	}
+
+	@Override
+	protected Bitmap transform(BitmapPool pool, Bitmap toTransform,
+			int outWidth, int outHeight) {
+		int width = toTransform.getWidth();
+		int height = toTransform.getHeight();
+
+		Bitmap bitmap = pool.get(width, height, ARGB_8888);
+		bitmap.setHasAlpha(true);
+
+		Canvas canvas = new Canvas(bitmap);
+		Paint paint = new Paint();
+		paint.setAntiAlias(true);
+		paint.setShader(new BitmapShader(toTransform, CLAMP, CLAMP));
+		drawRect(canvas, paint, width, height);
+		return bitmap;
+	}
+
+	private void drawRect(Canvas canvas, Paint paint, float width,
+			float height) {
+		drawTopLeft(canvas, paint, radii.topLeft, width, height);
+		drawTopRight(canvas, paint, radii.topRight, width, height);
+		drawBottomLeft(canvas, paint, radii.bottomLeft, width, height);
+		drawBottomRight(canvas, paint, radii.bottomRight, width, height);
+	}
+
+	private void drawTopLeft(Canvas canvas, Paint paint, int radius,
+			float width, float height) {
+		RectF rect = new RectF(
+				0,
+				0,
+				width / 2 + radius + 1,
+				height / 2 + radius + 1
+		);
+		if (radius == 0) canvas.drawRect(rect, paint);
+		else canvas.drawRoundRect(rect, radius, radius, paint);
+	}
+
+	private void drawTopRight(Canvas canvas, Paint paint, int radius,
+			float width, float height) {
+		RectF rect = new RectF(
+				width / 2 - radius,
+				0,
+				width,
+				height / 2 + radius + 1
+		);
+		if (radius == 0) canvas.drawRect(rect, paint);
+		else canvas.drawRoundRect(rect, radius, radius, paint);
+	}
+
+	private void drawBottomLeft(Canvas canvas, Paint paint, int radius,
+			float width, float height) {
+		RectF rect = new RectF(
+				0,
+				height / 2 - radius,
+				width / 2 + radius + 1,
+				height
+		);
+		if (radius == 0) canvas.drawRect(rect, paint);
+		else canvas.drawRoundRect(rect, radius, radius, paint);
+	}
+
+	private void drawBottomRight(Canvas canvas, Paint paint, int radius,
+			float width, float height) {
+		RectF rect = new RectF(
+				width / 2 - radius,
+				height / 2 - radius,
+				width,
+				height
+		);
+		if (radius == 0) canvas.drawRect(rect, paint);
+		else canvas.drawRoundRect(rect, radius, radius, paint);
+	}
+
+	@Override
+	public String toString() {
+		return "ImageCornerTransformation(" + radii + ")";
+	}
+
+	@Override
+	public boolean equals(Object o) {
+		return o instanceof CustomCornersTransformation &&
+				radii.equals(((CustomCornersTransformation) o).radii);
+	}
+
+	@Override
+	public int hashCode() {
+		return ID.hashCode() + radii.hashCode();
+	}
+
+	@Override
+	public void updateDiskCacheKey(@NonNull MessageDigest messageDigest) {
+		messageDigest.update((ID + radii).getBytes(CHARSET));
+	}
+
+}

briar-android/src/main/java/org/briarproject/briar/android/conversation/glide/ImageCornerTransformation.java

@@ -1,111 +0,0 @@
-package org.briarproject.briar.android.conversation.glide;
-
-import android.graphics.Bitmap;
-import android.graphics.BitmapShader;
-import android.graphics.Canvas;
-import android.graphics.Paint;
-import android.graphics.RectF;
-import android.support.annotation.NonNull;
-
-import com.bumptech.glide.load.engine.bitmap_recycle.BitmapPool;
-import com.bumptech.glide.load.resource.bitmap.BitmapTransformation;
-
-import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
-
-import java.security.MessageDigest;
-
-import javax.annotation.concurrent.Immutable;
-
-import static android.graphics.Bitmap.Config.ARGB_8888;
-import static android.graphics.Shader.TileMode.CLAMP;
-
-@Immutable
-@NotNullByDefault
-class ImageCornerTransformation extends BitmapTransformation {
-
-	private static final String ID = ImageCornerTransformation.class.getName();
-
-	private final int smallRadius, radius;
-	private final boolean leftCornerSmall, bottomRound;
-
-	ImageCornerTransformation(int smallRadius, int radius,
-			boolean leftCornerSmall, boolean bottomRound) {
-		this.smallRadius = smallRadius;
-		this.radius = radius;
-		this.leftCornerSmall = leftCornerSmall;
-		this.bottomRound = bottomRound;
-	}
-
-	@Override
-	protected Bitmap transform(BitmapPool pool, Bitmap toTransform,
-			int outWidth, int outHeight) {
-		int width = toTransform.getWidth();
-		int height = toTransform.getHeight();
-
-		Bitmap bitmap = pool.get(width, height, ARGB_8888);
-		bitmap.setHasAlpha(true);
-
-		Canvas canvas = new Canvas(bitmap);
-		Paint paint = new Paint();
-		paint.setAntiAlias(true);
-		paint.setShader(new BitmapShader(toTransform, CLAMP, CLAMP));
-		drawRect(canvas, paint, width, height);
-		return bitmap;
-	}
-
-	private void drawRect(Canvas canvas, Paint paint, float width,
-			float height) {
-		drawSmallCorner(canvas, paint, width);
-		drawBigCorners(canvas, paint, width, height);
-	}
-
-	private void drawSmallCorner(Canvas canvas, Paint paint, float width) {
-		float left = leftCornerSmall ? 0 : width - radius;
-		float right = leftCornerSmall ? radius : width;
-		canvas.drawRoundRect(new RectF(left, 0, right, radius),
-				smallRadius, smallRadius, paint);
-	}
-
-	private void drawBigCorners(Canvas canvas, Paint paint, float width,
-			float height) {
-		float top = bottomRound ? 0 : radius;
-		RectF rect = new RectF(0, top, width, height);
-		if (bottomRound) {
-			canvas.drawRoundRect(rect, radius, radius, paint);
-		} else {
-			canvas.drawRect(rect, paint);
-			canvas.drawRoundRect(new RectF(0, 0, width, radius * 2),
-					radius, radius, paint);
-		}
-	}
-
-	@Override
-	public String toString() {
-		return "ImageCornerTransformation(smallRadius=" + smallRadius +
-				", radius=" + radius + ", leftCornerSmall=" + leftCornerSmall +
-				", bottomRound=" + bottomRound + ")";
-	}
-
-	@Override
-	public boolean equals(Object o) {
-		return o instanceof ImageCornerTransformation &&
-				((ImageCornerTransformation) o).smallRadius == smallRadius &&
-				((ImageCornerTransformation) o).radius == radius &&
-				((ImageCornerTransformation) o).leftCornerSmall ==
-						leftCornerSmall &&
-				((ImageCornerTransformation) o).bottomRound == bottomRound;
-	}
-
-	@Override
-	public int hashCode() {
-		return ID.hashCode() + (smallRadius << 16) ^ (radius << 2) ^
-				(leftCornerSmall ? 2 : 0) ^ (bottomRound ? 1 : 0);
-	}
-
-	@Override
-	public void updateDiskCacheKey(@NonNull MessageDigest messageDigest) {
-		messageDigest.update((ID + '|' + smallRadius + '|' + radius + '|' +
-				leftCornerSmall + '|' + bottomRound).getBytes(CHARSET));
-	}
-
-}

briar-android/src/main/java/org/briarproject/briar/android/conversation/glide/Radii.java

@@ -0,0 +1,41 @@
+package org.briarproject.briar.android.conversation.glide;
+
+import android.support.annotation.Nullable;
+
+import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
+
+@NotNullByDefault
+public class Radii {
+
+	public final int topLeft, topRight, bottomLeft, bottomRight;
+
+	public Radii(int topLeft, int topRight, int bottomLeft, int bottomRight) {
+		this.topLeft = topLeft;
+		this.topRight = topRight;
+		this.bottomLeft = bottomLeft;
+		this.bottomRight = bottomRight;
+	}
+
+	@Override
+	public boolean equals(@Nullable Object o) {
+		return o instanceof Radii &&
+				topLeft == ((Radii) o).topLeft &&
+				topRight == ((Radii) o).topRight &&
+				bottomLeft == ((Radii) o).bottomLeft &&
+				bottomRight == ((Radii) o).bottomRight;
+	}
+
+	@Override
+	public int hashCode() {
+		return topLeft << 24 ^ topRight << 16 ^ bottomLeft << 8 ^ bottomRight;
+	}
+
+	@Override
+	public String toString() {
+		return "Radii(topLeft=" + topLeft +
+				",topRight=" + topRight +
+				",bottomLeft=" + bottomLeft +
+				",bottomRight=" + bottomRight;
+	}
+
+}

briar-android/src/main/java/org/briarproject/briar/android/forum/ForumActivity.java

@@ -134,12 +134,6 @@ public class ForumActivity extends
 		return MAX_FORUM_POST_TEXT_LENGTH;
 	}
 
-	@Override
-	@StringRes
-	protected int getItemPostedString() {
-		return R.string.forum_new_entry_posted;
-	}
-
 	private void showUnsubscribeDialog() {
 		OnClickListener okListener = (dialog, which) -> deleteForum();
 		AlertDialog.Builder builder = new AlertDialog.Builder(this,

briar-android/src/main/java/org/briarproject/briar/android/forum/ForumListFragment.java

@@ -44,6 +44,7 @@ import javax.annotation.Nullable;
 import javax.inject.Inject;
 
 import static android.support.design.widget.Snackbar.LENGTH_INDEFINITE;
+import static java.util.Objects.requireNonNull;
 import static java.util.logging.Level.WARNING;
 import static org.briarproject.bramble.util.LogUtils.logDuration;
 import static org.briarproject.bramble.util.LogUtils.logException;
@@ -80,13 +81,18 @@ public class ForumListFragment extends BaseEventFragment implements
 		return fragment;
 	}
 
+	@Override
+	public void injectFragment(ActivityComponent component) {
+		component.inject(this);
+	}
+
 	@Nullable
 	@Override
 	public View onCreateView(LayoutInflater inflater,
 			@Nullable ViewGroup container,
 			@Nullable Bundle savedInstanceState) {
 
-		getActivity().setTitle(R.string.forums_button);
+		requireNonNull(getActivity()).setTitle(R.string.forums_button);
 
 		View contentView =
 				inflater.inflate(R.layout.fragment_forum_list, container,
@@ -102,7 +108,7 @@ public class ForumListFragment extends BaseEventFragment implements
 		snackbar.getView().setBackgroundResource(R.color.briar_primary);
 		snackbar.setAction(R.string.show, this);
 		snackbar.setActionTextColor(ContextCompat
-				.getColor(getContext(), R.color.briar_button_text_positive));
+				.getColor(getActivity(), R.color.briar_button_text_positive));
 
 		return contentView;
 	}
@@ -112,11 +118,6 @@ public class ForumListFragment extends BaseEventFragment implements
 		return TAG;
 	}
 
-	@Override
-	public void injectFragment(ActivityComponent component) {
-		component.inject(this);
-	}
-
 	@Override
 	public void onStart() {
 		super.onStart();

briar-android/src/main/java/org/briarproject/briar/android/fragment/BaseFragment.java

@@ -10,11 +10,15 @@ import android.support.v4.app.FragmentActivity;
 import android.view.MenuItem;
 
 import org.briarproject.bramble.api.db.DbException;
+import org.briarproject.bramble.api.nullsafety.MethodsNotNullByDefault;
+import org.briarproject.bramble.api.nullsafety.ParametersNotNullByDefault;
 import org.briarproject.briar.android.DestroyableContext;
 import org.briarproject.briar.android.activity.ActivityComponent;
 
 import javax.annotation.Nullable;
 
+@MethodsNotNullByDefault
+@ParametersNotNullByDefault
 public abstract class BaseFragment extends Fragment
 		implements DestroyableContext {
 
@@ -22,12 +26,15 @@ public abstract class BaseFragment extends Fragment
 
 	public abstract String getUniqueTag();
 
-	public abstract void injectFragment(ActivityComponent component);
-
 	@Override
 	public void onAttach(Context context) {
 		super.onAttach(context);
 		listener = (BaseFragmentListener) context;
+		injectFragment(listener.getActivityComponent());
+	}
+
+	public void injectFragment(ActivityComponent component) {
+		// fragments that need to inject, can override this method
 	}
 
 	@Override
@@ -38,12 +45,6 @@ public abstract class BaseFragment extends Fragment
 		setHasOptionsMenu(true);
 	}
 
-	@Override
-	public void onActivityCreated(@Nullable Bundle savedInstanceState) {
-		super.onActivityCreated(savedInstanceState);
-		injectFragment(listener.getActivityComponent());
-	}
-
 	@Override
 	public boolean onOptionsItemSelected(MenuItem item) {
 		switch (item.getItemId()) {

briar-android/src/main/java/org/briarproject/briar/android/fragment/ErrorFragment.java

@@ -10,7 +10,6 @@ import android.widget.TextView;
 import org.briarproject.bramble.api.nullsafety.MethodsNotNullByDefault;
 import org.briarproject.bramble.api.nullsafety.ParametersNotNullByDefault;
 import org.briarproject.briar.R;
-import org.briarproject.briar.android.activity.ActivityComponent;
 
 
 @MethodsNotNullByDefault
@@ -57,9 +56,4 @@ public class ErrorFragment extends BaseFragment {
 		return v;
 	}
 
-	@Override
-	public void injectFragment(ActivityComponent component) {
-		// not necessary
-	}
-
 }

briar-android/src/main/java/org/briarproject/briar/android/introduction/ContactChooserFragment.java

@@ -1,7 +1,8 @@
 package org.briarproject.briar.android.introduction;
 
-import android.content.Context;
 import android.os.Bundle;
+import android.support.annotation.Nullable;
+import android.support.annotation.UiThread;
 import android.support.v7.widget.LinearLayoutManager;
 import android.view.LayoutInflater;
 import android.view.View;
@@ -11,6 +12,8 @@ import org.briarproject.bramble.api.contact.Contact;
 import org.briarproject.bramble.api.contact.ContactId;
 import org.briarproject.bramble.api.contact.ContactManager;
 import org.briarproject.bramble.api.db.DbException;
+import org.briarproject.bramble.api.nullsafety.MethodsNotNullByDefault;
+import org.briarproject.bramble.api.nullsafety.ParametersNotNullByDefault;
 import org.briarproject.bramble.api.plugin.ConnectionRegistry;
 import org.briarproject.briar.R;
 import org.briarproject.briar.android.activity.ActivityComponent;
@@ -28,10 +31,14 @@ import java.util.logging.Logger;
 
 import javax.inject.Inject;
 
+import static java.util.Objects.requireNonNull;
 import static java.util.logging.Level.WARNING;
 import static org.briarproject.bramble.util.LogUtils.logException;
 import static org.briarproject.briar.android.conversation.ConversationActivity.CONTACT_ID;
 
+@UiThread
+@MethodsNotNullByDefault
+@ParametersNotNullByDefault
 public class ContactChooserFragment extends BaseFragment {
 
 	public static final String TAG = ContactChooserFragment.class.getName();
@@ -51,7 +58,6 @@ public class ContactChooserFragment extends BaseFragment {
 	volatile ConnectionRegistry connectionRegistry;
 
 	public static ContactChooserFragment newInstance(ContactId id) {
-
 		Bundle args = new Bundle();
 
 		ContactChooserFragment fragment = new ContactChooserFragment();
@@ -61,13 +67,13 @@ public class ContactChooserFragment extends BaseFragment {
 	}
 
 	@Override
-	public void onAttach(Context context) {
-		super.onAttach(context);
+	public void injectFragment(ActivityComponent component) {
+		component.inject(this);
 	}
 
 	@Override
-	public View onCreateView(LayoutInflater inflater, ViewGroup container,
-			Bundle savedInstanceState) {
+	public View onCreateView(LayoutInflater inflater, @Nullable ViewGroup container,
+			@Nullable Bundle savedInstanceState) {
 
 		View contentView = inflater.inflate(R.layout.list, container, false);
 
@@ -77,14 +83,16 @@ public class ContactChooserFragment extends BaseFragment {
 					Contact c2 = item.getContact();
 					showMessageScreen(c1, c2);
 				};
-		adapter = new ContactListAdapter(getActivity(), onContactClickListener);
+		adapter = new ContactListAdapter(requireNonNull(getActivity()),
+				onContactClickListener);
 
 		list = contentView.findViewById(R.id.list);
 		list.setLayoutManager(new LinearLayoutManager(getActivity()));
 		list.setAdapter(adapter);
 		list.setEmptyText(R.string.no_contacts);
 
-		contactId = new ContactId(getArguments().getInt(CONTACT_ID));
+		contactId = new ContactId(
+				requireNonNull(getArguments()).getInt(CONTACT_ID));
 
 		return contentView;
 	}
@@ -107,11 +115,6 @@ public class ContactChooserFragment extends BaseFragment {
 		return TAG;
 	}
 
-	@Override
-	public void injectFragment(ActivityComponent component) {
-		component.inject(this);
-	}
-
 	private void loadContacts() {
 		listener.runOnDbThread(() -> {
 			try {

briar-android/src/main/java/org/briarproject/briar/android/introduction/IntroductionMessageFragment.java

@@ -1,8 +1,8 @@
 package org.briarproject.briar.android.introduction;
 
 import android.content.Context;
+import android.net.Uri;
 import android.os.Bundle;
-import android.support.annotation.NonNull;
 import android.support.annotation.Nullable;
 import android.support.v7.app.ActionBar;
 import android.view.LayoutInflater;
@@ -17,14 +17,17 @@ import org.briarproject.bramble.api.contact.Contact;
 import org.briarproject.bramble.api.contact.ContactId;
 import org.briarproject.bramble.api.contact.ContactManager;
 import org.briarproject.bramble.api.db.DbException;
-import org.briarproject.bramble.util.StringUtils;
+import org.briarproject.bramble.api.nullsafety.MethodsNotNullByDefault;
+import org.briarproject.bramble.api.nullsafety.ParametersNotNullByDefault;
 import org.briarproject.briar.R;
 import org.briarproject.briar.android.activity.ActivityComponent;
 import org.briarproject.briar.android.fragment.BaseFragment;
 import org.briarproject.briar.android.view.TextInputView;
-import org.briarproject.briar.android.view.TextInputView.TextInputListener;
+import org.briarproject.briar.android.view.TextSendController;
+import org.briarproject.briar.android.view.TextSendController.SendListener;
 import org.briarproject.briar.api.introduction.IntroductionManager;
 
+import java.util.List;
 import java.util.logging.Logger;
 
 import javax.inject.Inject;
@@ -36,13 +39,16 @@ import static android.app.Activity.RESULT_OK;
 import static android.view.View.GONE;
 import static android.view.View.VISIBLE;
 import static android.widget.Toast.LENGTH_SHORT;
+import static java.util.Objects.requireNonNull;
 import static java.util.logging.Level.WARNING;
 import static org.briarproject.bramble.util.LogUtils.logException;
 import static org.briarproject.briar.android.util.UiUtils.getContactDisplayName;
 import static org.briarproject.briar.api.introduction.IntroductionConstants.MAX_INTRODUCTION_TEXT_LENGTH;
 
+@MethodsNotNullByDefault
+@ParametersNotNullByDefault
 public class IntroductionMessageFragment extends BaseFragment
-		implements TextInputListener {
+		implements SendListener {
 
 	public static final String TAG =
 			IntroductionMessageFragment.class.getName();
@@ -72,11 +78,6 @@ public class IntroductionMessageFragment extends BaseFragment
 		return fragment;
 	}
 
-	@Override
-	public void injectFragment(ActivityComponent component) {
-		component.inject(this);
-	}
-
 	@Override
 	public void onAttach(Context context) {
 		super.onAttach(context);
@@ -84,8 +85,14 @@ public class IntroductionMessageFragment extends BaseFragment
 	}
 
 	@Override
-	public View onCreateView(@NonNull LayoutInflater inflater,
-			ViewGroup container, Bundle savedInstanceState) {
+	public void injectFragment(ActivityComponent component) {
+		component.inject(this);
+	}
+
+	@Override
+	public View onCreateView(LayoutInflater inflater,
+			@Nullable ViewGroup container,
+			@Nullable Bundle savedInstanceState) {
 
 		// change toolbar text
 		ActionBar actionBar = introductionActivity.getSupportActionBar();
@@ -93,11 +100,26 @@ public class IntroductionMessageFragment extends BaseFragment
 			actionBar.setTitle(R.string.introduction_message_title);
 		}
 
+		// get contact IDs from fragment arguments
+		Bundle args = requireNonNull(getArguments());
+		int contactId1 = args.getInt(CONTACT_ID_1, -1);
+		int contactId2 = args.getInt(CONTACT_ID_2, -1);
+		if (contactId1 == -1 || contactId2 == -1) {
+			throw new AssertionError("Use newInstance() to instantiate");
+		}
+
 		// inflate view
 		View v = inflater.inflate(R.layout.introduction_message, container,
 				false);
 		ui = new ViewHolder(v);
-		ui.message.setSendButtonEnabled(false);
+		TextSendController sendController =
+				new TextSendController(ui.message, this, true);
+		ui.message.setSendController(sendController);
+		ui.message.setMaxTextLength(MAX_INTRODUCTION_TEXT_LENGTH);
+		ui.message.setEnabled(false);
+
+		// get contacts and then show view
+		prepareToSetUpViews(contactId1, contactId2);
 
 		return v;
 	}
@@ -105,16 +127,6 @@ public class IntroductionMessageFragment extends BaseFragment
 	@Override
 	public void onStart() {
 		super.onStart();
-
-		// get contact IDs from fragment arguments
-		int contactId1 = getArguments().getInt(CONTACT_ID_1, -1);
-		int contactId2 = getArguments().getInt(CONTACT_ID_2, -1);
-		if (contactId1 == -1 || contactId2 == -1) {
-			throw new java.lang.InstantiationError(
-					"You need to use newInstance() to instantiate");
-		}
-		// get contacts and then show view
-		prepareToSetUpViews(contactId1, contactId2);
 	}
 
 	@Override
@@ -156,13 +168,10 @@ public class IntroductionMessageFragment extends BaseFragment
 			ui.progressBar.setVisibility(GONE);
 
 			if (possible) {
-				// set button action
-				ui.message.setListener(IntroductionMessageFragment.this);
-
 				// show views
 				ui.notPossible.setVisibility(GONE);
 				ui.message.setVisibility(VISIBLE);
-				ui.message.setSendButtonEnabled(true);
+				ui.message.setEnabled(true);
 				ui.message.showSoftKeyboard();
 			} else {
 				ui.notPossible.setVisibility(VISIBLE);
@@ -184,14 +193,11 @@ public class IntroductionMessageFragment extends BaseFragment
 	}
 
 	@Override
-	public void onSendClick(@NonNull String text) {
+	public void onSendClick(@Nullable String text, List<Uri> imageUris) {
 		// disable button to prevent accidental double invitations
-		ui.message.setSendButtonEnabled(false);
+		ui.message.setEnabled(false);
 
-		String txt = ui.message.getText().toString();
-		if (txt.isEmpty()) txt = null;
-		else txt = StringUtils.truncateUtf8(txt, MAX_INTRODUCTION_TEXT_LENGTH);
-		makeIntroduction(contact1, contact2, txt);
+		makeIntroduction(contact1, contact2, text);
 
 		// don't wait for the introduction to be made before finishing activity
 		introductionActivity.hideSoftKeyboard(ui.message);

briar-android/src/main/java/org/briarproject/briar/android/keyagreement/ContactExchangeActivity.java

@@ -4,9 +4,12 @@ import android.os.Bundle;
 import android.support.annotation.UiThread;
 import android.widget.Toast;
 
-import org.briarproject.bramble.api.contact.ContactExchangeListener;
 import org.briarproject.bramble.api.contact.ContactExchangeTask;
+import org.briarproject.bramble.api.contact.event.ContactExchangeFailedEvent;
+import org.briarproject.bramble.api.contact.event.ContactExchangeSucceededEvent;
 import org.briarproject.bramble.api.db.DbException;
+import org.briarproject.bramble.api.event.Event;
+import org.briarproject.bramble.api.event.EventListener;
 import org.briarproject.bramble.api.identity.Author;
 import org.briarproject.bramble.api.identity.IdentityManager;
 import org.briarproject.bramble.api.identity.LocalAuthor;
@@ -28,7 +31,7 @@ import static org.briarproject.bramble.util.LogUtils.logException;
 @MethodsNotNullByDefault
 @ParametersNotNullByDefault
 public class ContactExchangeActivity extends KeyAgreementActivity implements
-		ContactExchangeListener {
+		EventListener {
 
 	private static final Logger LOG =
 			Logger.getLogger(ContactExchangeActivity.class.getName());
@@ -50,6 +53,20 @@ public class ContactExchangeActivity extends KeyAgreementActivity implements
 		getSupportActionBar().setTitle(R.string.add_contact_title);
 	}
 
+	@Override
+	public void onStart() {
+		super.onStart();
+		// Listen to updates from contactExchangeTask
+		eventBus.addListener(this);
+	}
+
+	@Override
+	protected void onStop() {
+		super.onStop();
+		// Stop listen to updates from contactExchangeTask
+		eventBus.addListener(this);
+	}
+
 	private void startContactExchange(KeyAgreementResult result) {
 		runOnDbThread(() -> {
 			LocalAuthor localAuthor;
@@ -63,15 +80,28 @@ public class ContactExchangeActivity extends KeyAgreementActivity implements
 			}
 
 			// Exchange contact details
-			contactExchangeTask.startExchange(ContactExchangeActivity.this,
-					localAuthor, result.getMasterKey(),
-					result.getConnection(), result.getTransportId(),
-					result.wasAlice());
+			contactExchangeTask.startExchange(localAuthor,
+					result.getMasterKey(), result.getConnection(),
+					result.getTransportId(), result.wasAlice());
 		});
 	}
 
 	@Override
-	public void contactExchangeSucceeded(Author remoteAuthor) {
+	public void eventOccurred(Event e) {
+		if (e instanceof ContactExchangeSucceededEvent) {
+			contactExchangeSucceeded(
+					((ContactExchangeSucceededEvent) e).getRemoteAuthor());
+		} else if (e instanceof ContactExchangeFailedEvent) {
+			ContactExchangeFailedEvent fe = (ContactExchangeFailedEvent) e;
+			if (fe.wasDuplicateContact()) {
+				duplicateContact(fe.getDuplicateRemoteAuthor());
+			} else {
+				contactExchangeFailed();
+			}
+		}
+	}
+
+	private void contactExchangeSucceeded(Author remoteAuthor) {
 		runOnUiThreadUnlessDestroyed(() -> {
 			String contactName = remoteAuthor.getName();
 			String format = getString(R.string.contact_added_toast);
@@ -82,8 +112,7 @@ public class ContactExchangeActivity extends KeyAgreementActivity implements
 		});
 	}
 
-	@Override
-	public void duplicateContact(Author remoteAuthor) {
+	private void duplicateContact(Author remoteAuthor) {
 		runOnUiThreadUnlessDestroyed(() -> {
 			String contactName = remoteAuthor.getName();
 			String format = getString(R.string.contact_already_exists);
@@ -94,8 +123,7 @@ public class ContactExchangeActivity extends KeyAgreementActivity implements
 		});
 	}
 
-	@Override
-	public void contactExchangeFailed() {
+	private void contactExchangeFailed() {
 		runOnUiThreadUnlessDestroyed(() -> {
 			showErrorFragment(R.string.connection_error_explanation);
 		});

briar-android/src/main/java/org/briarproject/briar/android/keyagreement/ContactExchangeErrorFragment.java

@@ -44,6 +44,11 @@ public class ContactExchangeErrorFragment extends BaseFragment {
 		return TAG;
 	}
 
+	@Override
+	public void injectFragment(ActivityComponent component) {
+		component.inject(this);
+	}
+
 	@Nullable
 	@Override
 	public View onCreateView(LayoutInflater inflater,
@@ -74,11 +79,6 @@ public class ContactExchangeErrorFragment extends BaseFragment {
 		return v;
 	}
 
-	@Override
-	public void injectFragment(ActivityComponent component) {
-		component.inject(this);
-	}
-
 	private void triggerFeedback() {
 		finish();
 		UiUtils.triggerFeedback(androidExecutor);