merge with 1872-key-agreement

bramble-android/build.gradle

@@ -8,11 +8,15 @@ android {
 	compileSdkVersion 30
 	buildToolsVersion '30.0.2'
 
+	packagingOptions {
+		doNotStrip '**/*.so'
+	}
+
 	defaultConfig {
 		minSdkVersion 16
 		targetSdkVersion 29
-		versionCode 10216
+		versionCode 10218
-		versionName "1.2.16"
+		versionName "1.2.18"
 		consumerProguardFiles 'proguard-rules.txt'
 
 		testInstrumentationRunner "androidx.test.runner.AndroidJUnitRunner"

bramble-android/src/main/java/org/briarproject/bramble/plugin/bluetooth/AndroidBluetoothPlugin.java

@@ -175,6 +175,11 @@ class AndroidBluetoothPlugin
 		} catch (IOException e) {
 			IoUtils.tryToClose(s, LOG, WARNING);
 			throw e;
+		} catch (NullPointerException e) {
+			// BluetoothSocket#connect() may throw an NPE under unknown
+			// circumstances
+			IoUtils.tryToClose(s, LOG, WARNING);
+			throw new IOException(e);
 		}
 	}
 

bramble-android/src/main/java/org/briarproject/bramble/util/AndroidUtils.java

@@ -114,12 +114,8 @@ public class AndroidUtils {
 
 	/**
 	 * Returns an array of supported content types for image attachments.
-	 * GIFs can't be compressed on API < 24 so they're not supported.
-	 * <p>
-	 * TODO: Remove this restriction when large message support is added
 	 */
 	public static String[] getSupportedImageContentTypes() {
-		if (SDK_INT < 24) return new String[] {"image/jpeg", "image/png"};
+		return new String[] {"image/jpeg", "image/png", "image/gif"};
-		else return new String[] {"image/jpeg", "image/png", "image/gif"};
 	}
 }

bramble-core/src/main/java/org/briarproject/bramble/keyagreement/KeyAgreementTransport.java

@@ -34,12 +34,12 @@ class KeyAgreementTransport {
 			Logger.getLogger(KeyAgreementTransport.class.getName());
 
 	// Accept records with current protocol version, known record type
-	private static Predicate<Record> ACCEPT = r ->
+	private static final Predicate<Record> ACCEPT = r ->
 			r.getProtocolVersion() == PROTOCOL_VERSION &&
 					isKnownRecordType(r.getRecordType());
 
 	// Ignore records with current protocol version, unknown record type
-	private static Predicate<Record> IGNORE = r ->
+	private static final Predicate<Record> IGNORE = r ->
 			r.getProtocolVersion() == PROTOCOL_VERSION &&
 					!isKnownRecordType(r.getRecordType());
 

bramble-core/src/main/resources/bridges

@@ -2,12 +2,11 @@ Bridge obfs4 192.95.36.142:443 CDF2E852BF539B82BD10E27E9115A31734E378C2 cert=qUV
 Bridge obfs4 38.229.1.78:80 C8CBDB2464FC9804A69531437BCF2BE31FDD2EE4 cert=Hmyfd2ev46gGY7NoVxA9ngrPF2zCZtzskRTzoWXbxNkzeVnGFPWmrTtILRyqCTjHR+s9dg iat-mode=1
 Bridge obfs4 37.218.245.14:38224 D9A82D2F9C2F65A18407B1D2B764F130847F8B5D cert=bjRaMrr1BRiAW8IE9U5z27fQaYgOhX1UCmOpg2pFpoMvo6ZgQMzLsaTzzQNTlm7hNcb+Sg iat-mode=0
 Bridge obfs4 85.31.186.98:443 011F2599C0E9B27EE74B353155E244813763C3E5 cert=ayq0XzCwhpdysn5o0EyDUbmSOx3X/oTEbzDMvczHOdBJKlvIdHHLJGkZARtT4dcBFArPPg iat-mode=0
-Bridge obfs4 85.31.186.26:443 91A6354697E6B02A386312F68D82CF86824D3606 cert=PBwr+S8JTVZo6MPdHnkTwXJPILWADLqfMGoVvhZClMq/Urndyd42BwX9YFJHZnBB3H0XCw iat-mode=0
+Bridge obfs4 144.217.20.138:80 FB70B257C162BF1038CA669D568D76F5B7F0BABB cert=vYIV5MgrghGQvZPIi1tJwnzorMgqgmlKaB77Y3Z9Q/v94wZBOAXkW+fdx4aSxLVnKO+xNw iat-mode=0
 Bridge obfs4 193.11.166.194:27015 2D82C2E354D531A68469ADF7F878FA6060C6BACA cert=4TLQPJrTSaDffMK7Nbao6LC7G9OW/NHkUwIdjLSS3KYf0Nv4/nQiiI8dY2TcsQx01NniOg iat-mode=0
 Bridge obfs4 193.11.166.194:27020 86AC7B8D430DAC4117E9F42C9EAED18133863AAF cert=0LDeJH4JzMDtkJJrFphJCiPqKx7loozKN7VNfuukMGfHO0Z8OGdzHVkhVAOfo1mUdv9cMg iat-mode=0
 Bridge obfs4 193.11.166.194:27025 1AE2C08904527FEA90C4C4F8C1083EA59FBC6FAF cert=ItvYZzW5tn6v3G4UnQa6Qz04Npro6e81AP70YujmK/KXwDFPTs3aHXcHp4n8Vt6w/bv8cA iat-mode=0
 Bridge obfs4 209.148.46.65:443 74FAD13168806246602538555B5521A0383A1875 cert=ssH+9rP8dG2NLDN2XuFw63hIO/9MNNinLmxQDpVa+7kTOa9/m+tGWT1SmSYpQ9uTBGa6Hw iat-mode=0
-Bridge obfs4 146.57.248.225:22 10A6CD36A537FCE513A322361547444B393989F0 cert=K1gDtDAIcUfeLqbstggjIw2rtgIKqdIhUlHp82XRqNSq/mtAjp1BIC9vHKJ2FAEpGssTPw iat-mode=0
 Bridge obfs4 45.145.95.6:27015 C5B7CD6946FF10C5B3E89691A7D3F2C122D2117C cert=TD7PbUO0/0k6xYHMPW3vJxICfkMZNdkRrb63Zhl5j9dW3iRGiCx0A7mPhe5T2EDzQ35+Zw iat-mode=0
 Bridge obfs4 51.222.13.177:80 5EDAC3B810E12B01F6FD8050D2FD3E277B289A08 cert=2uplIpLQ0q9+0qMFrK5pkaYRDOe460LL9WHBvatgkuRr/SL31wBOEupaMMJ6koRE6Ld0ew iat-mode=0
 Bridge obfs4 78.46.188.239:37356 5A2D2F4158D0453E00C7C176978D3F41D69C45DB cert=3c0SwxpOisbohNxEc4tb875RVW8eOu1opRTVXJhafaKA/PNNtI7ElQIVOVZg1AdL5bxGCw iat-mode=0

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:0.3.5.13@zip'
+	tor 'org.briarproject:tor:0.3.5.13-1@zip'
 	tor 'org.briarproject:obfs4proxy:0.0.12-dev-40245c4a@zip'
 
 	annotationProcessor 'com.google.dagger:dagger-compiler:2.24'

bramble-java/src/main/java/org/briarproject/bramble/plugin/tor/UnixTorPluginFactory.java

@@ -25,6 +25,7 @@ import javax.annotation.concurrent.Immutable;
 import javax.inject.Inject;
 import javax.net.SocketFactory;
 
+import static java.util.logging.Level.INFO;
 import static java.util.logging.Logger.getLogger;
 import static org.briarproject.bramble.util.OsUtils.isLinux;
 
@@ -96,8 +97,15 @@ public class UnixTorPluginFactory implements DuplexPluginFactory {
 		String architecture = null;
 		if (isLinux()) {
 			String arch = System.getProperty("os.arch");
+			if (LOG.isLoggable(INFO)) {
+				LOG.info("System's os.arch is " + arch);
+			}
 			if (arch.equals("amd64")) {
 				architecture = "linux-x86_64";
+			} else if (arch.equals("aarch64")) {
+				architecture = "linux-aarch64";
+			} else if (arch.equals("arm")) {
+				architecture = "linux-armhf";
 			}
 		}
 		if (architecture == null) {
@@ -105,6 +113,10 @@ public class UnixTorPluginFactory implements DuplexPluginFactory {
 			return null;
 		}
 
+		if (LOG.isLoggable(INFO)) {
+			LOG.info("The selected architecture for Tor is " + architecture);
+		}
+
 		Backoff backoff = backoffFactory.createBackoff(MIN_POLLING_INTERVAL,
 				MAX_POLLING_INTERVAL, BACKOFF_BASE);
 		TorRendezvousCrypto torRendezvousCrypto = new TorRendezvousCryptoImpl();

bramble-java/witness.gradle

@@ -24,7 +24,7 @@ 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:0.0.12-dev-40245c4a:obfs4proxy-0.0.12-dev-40245c4a.zip:172029e7058b3a83ac93ac4991a44bf76e16ce8d46f558f5836d57da3cb3a766',
-        'org.briarproject:tor:0.3.5.13:tor-0.3.5.13.zip:1c5f0b821ee2aadb0ea04aa96caab3ca0a08370cce8de81c2dfe04d172f8a2a0',
+        'org.briarproject:tor:0.3.5.13-1:tor-0.3.5.13-1.zip:ef35c16bf8dc1f4c75ed71d9f55e4514f383d124ec96b859aca647c990927c99',
         'org.checkerframework:checker-compat-qual:2.5.3:checker-compat-qual-2.5.3.jar:d76b9afea61c7c082908023f0cbc1427fab9abd2df915c8b8a3e7a509bccbc6d',
         'org.checkerframework:checker-qual:2.5.2:checker-qual-2.5.2.jar:64b02691c8b9d4e7700f8ee2e742dce7ea2c6e81e662b7522c9ee3bf568c040a',
         'org.codehaus.mojo:animal-sniffer-annotations:1.17:animal-sniffer-annotations-1.17.jar:92654f493ecfec52082e76354f0ebf87648dc3d5cec2e3c3cdb947c016747a53',

briar-android/build.gradle

@@ -19,12 +19,16 @@ android {
 	compileSdkVersion 30
 	buildToolsVersion '30.0.2'
 
+	packagingOptions {
+		doNotStrip '**/*.so'
+	}
+
 	defaultConfig {
 		minSdkVersion 16
 		targetSdkVersion 29
-		versionCode 10216
+		versionCode 10218
-		versionName "1.2.16"
+		versionName "1.2.18"
-		applicationId "org.briarproject.briar.socialbackup"
+		applicationId "org.briarproject.briar.android"
 
 		vectorDrawables.useSupportLibrary = true
 		buildConfigField "String", "GitHash",
@@ -95,6 +99,7 @@ dependencies {
 	implementation project(path: ':bramble-core', configuration: 'default')
 	implementation project(':bramble-android')
 
+	implementation 'androidx.fragment:fragment:1.3.0'
 	implementation 'androidx.preference:preference:1.1.1'
 	implementation 'androidx.exifinterface:exifinterface:1.3.1'
 	implementation 'androidx.lifecycle:lifecycle-extensions:2.2.0'

briar-android/src/main/AndroidManifest.xml

@@ -27,7 +27,10 @@
 	<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
+		android:name="android.permission.WRITE_EXTERNAL_STORAGE"
+		android:maxSdkVersion="18"
+		tools:ignore="ScopedStorage" />
 
 	<uses-permission-sdk-23 android:name="android.permission.ACCESS_FINE_LOCATION" />
 	<uses-permission-sdk-23 android:name="android.permission.REQUEST_IGNORE_BATTERY_OPTIMIZATIONS" />
@@ -38,6 +41,7 @@
 		android:name="org.briarproject.briar.android.BriarApplicationImpl"
 		android:allowBackup="false"
 		android:banner="@mipmap/tv_banner"
+		android:fullBackupContent="@xml/backup_rules"
 		android:icon="@mipmap/ic_launcher_round"
 		android:label="@string/app_name"
 		android:logo="@mipmap/ic_launcher_round"
@@ -374,7 +378,7 @@
 		</activity>
 
 		<activity
-			android:name="org.briarproject.briar.android.keyagreement.ContactExchangeActivity"
+			android:name="org.briarproject.briar.android.contact.add.nearby.AddNearbyContactActivity"
 			android:label="@string/add_contact_title"
 			android:parentActivityName="org.briarproject.briar.android.navdrawer.NavDrawerActivity"
 			android:theme="@style/BriarTheme.NoActionBar">

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

@@ -31,8 +31,9 @@ import org.briarproject.briar.android.account.DozeHelperModule;
 import org.briarproject.briar.android.account.LockManagerImpl;
 import org.briarproject.briar.android.account.SetupModule;
 import org.briarproject.briar.android.contact.ContactListModule;
+import org.briarproject.briar.android.contact.add.nearby.AddNearbyContactModule;
 import org.briarproject.briar.android.forum.ForumModule;
-import org.briarproject.briar.android.keyagreement.ContactExchangeModule;
+import org.briarproject.briar.android.introduction.IntroductionModule;
 import org.briarproject.briar.android.logging.LoggingModule;
 import org.briarproject.briar.android.login.LoginModule;
 import org.briarproject.briar.android.navdrawer.NavDrawerModule;
@@ -75,7 +76,7 @@ import static org.briarproject.briar.android.TestingConstants.IS_DEBUG_BUILD;
 @Module(includes = {
 		SetupModule.class,
 		DozeHelperModule.class,
-		ContactExchangeModule.class,
+		AddNearbyContactModule.class,
 		LoggingModule.class,
 		LoginModule.class,
 		NavDrawerModule.class,
@@ -84,6 +85,7 @@ import static org.briarproject.briar.android.TestingConstants.IS_DEBUG_BUILD;
 		DevReportModule.class,
 		ContactListModule.class,
 		AndroidDarkCrystalModule.class,
+		IntroductionModule.class,
 		// below need to be within same scope as ViewModelProvider.Factory
 		ForumModule.class,
 		GroupListModule.class,

briar-android/src/main/java/org/briarproject/briar/android/account/DozeFragment.java

@@ -33,7 +33,6 @@ public class DozeFragment extends SetupFragment
 	private DozeView dozeView;
 	private HuaweiView huaweiView;
 	private Button next;
-	private ProgressBar progressBar;
 	private boolean secondAttempt = false;
 
 	public static DozeFragment newInstance() {
@@ -58,11 +57,19 @@ public class DozeFragment extends SetupFragment
 		huaweiView = v.findViewById(R.id.huaweiView);
 		huaweiView.setOnCheckedChangedListener(this);
 		next = v.findViewById(R.id.next);
-		progressBar = v.findViewById(R.id.progress);
+		ProgressBar progressBar = v.findViewById(R.id.progress);
 
 		dozeView.setOnButtonClickListener(this::askForDozeWhitelisting);
 		next.setOnClickListener(this);
 
+		viewModel.getIsCreatingAccount()
+				.observe(getViewLifecycleOwner(), isCreatingAccount -> {
+					if (isCreatingAccount) {
+						next.setVisibility(INVISIBLE);
+						progressBar.setVisibility(VISIBLE);
+					}
+				});
+
 		return v;
 	}
 
@@ -104,15 +111,6 @@ public class DozeFragment extends SetupFragment
 
 	@Override
 	public void onClick(View view) {
-		setNextClicked();
 		viewModel.dozeExceptionConfirmed();
 	}
-
-	@Override
-	void setNextClicked() {
-		super.setNextClicked();
-
-		next.setVisibility(INVISIBLE);
-		progressBar.setVisibility(VISIBLE);
-	}
 }

briar-android/src/main/java/org/briarproject/briar/android/account/SetPasswordFragment.java

@@ -38,7 +38,6 @@ public class SetPasswordFragment extends SetupFragment {
 	private TextInputEditText passwordConfirmation;
 	private StrengthMeter strengthMeter;
 	private Button nextButton;
-	private ProgressBar progressBar;
 
 	public static SetPasswordFragment newInstance() {
 		return new SetPasswordFragment();
@@ -64,7 +63,7 @@ public class SetPasswordFragment extends SetupFragment {
 				v.findViewById(R.id.password_confirm_wrapper);
 		passwordConfirmation = v.findViewById(R.id.password_confirm);
 		nextButton = v.findViewById(R.id.next);
-		progressBar = v.findViewById(R.id.progress);
+		ProgressBar progressBar = v.findViewById(R.id.progress);
 
 		passwordEntry.addTextChangedListener(this);
 		passwordConfirmation.addTextChangedListener(this);
@@ -75,6 +74,17 @@ public class SetPasswordFragment extends SetupFragment {
 			passwordConfirmation.setImeOptions(IME_ACTION_DONE);
 		}
 
+		viewModel.getIsCreatingAccount()
+				.observe(getViewLifecycleOwner(), isCreatingAccount -> {
+					if (isCreatingAccount) {
+						nextButton.setVisibility(INVISIBLE);
+						progressBar.setVisibility(VISIBLE);
+						// this also avoids the keyboard popping up
+						passwordEntry.setFocusable(false);
+						passwordConfirmation.setFocusable(false);
+					}
+				});
+
 		return v;
 	}
 
@@ -116,20 +126,6 @@ public class SetPasswordFragment extends SetupFragment {
 		IBinder token = passwordEntry.getWindowToken();
 		Object o = getContext().getSystemService(INPUT_METHOD_SERVICE);
 		((InputMethodManager) o).hideSoftInputFromWindow(token, 0);
-
-		setNextClicked();
 		viewModel.setPassword(passwordEntry.getText().toString());
 	}
-
-	@Override
-	void setNextClicked() {
-		super.setNextClicked();
-
-		passwordEntry.setFocusable(false);
-		passwordConfirmation.setFocusable(false);
-		if (!viewModel.needToShowDozeFragment()) {
-			nextButton.setVisibility(INVISIBLE);
-			progressBar.setVisibility(VISIBLE);
-		}
-	}
 }

briar-android/src/main/java/org/briarproject/briar/android/account/SetupFragment.java

@@ -7,7 +7,6 @@ import android.view.KeyEvent;
 import android.view.Menu;
 import android.view.MenuInflater;
 import android.view.MenuItem;
-import android.view.View;
 import android.view.View.OnClickListener;
 import android.widget.TextView;
 import android.widget.TextView.OnEditorActionListener;
@@ -19,8 +18,6 @@ import org.briarproject.briar.android.fragment.BaseFragment;
 
 import javax.inject.Inject;
 
-import androidx.annotation.CallSuper;
-import androidx.annotation.NonNull;
 import androidx.annotation.Nullable;
 import androidx.lifecycle.ViewModelProvider;
 
@@ -35,7 +32,6 @@ abstract class SetupFragment extends BaseFragment implements TextWatcher,
 		OnEditorActionListener, OnClickListener {
 
 	private final static String STATE_KEY_CLICKED = "setupFragmentClicked";
-	private boolean clicked = false;
 
 	@Inject
 	ViewModelProvider.Factory viewModelFactory;
@@ -48,27 +44,6 @@ abstract class SetupFragment extends BaseFragment implements TextWatcher,
 				.get(SetupViewModel.class);
 	}
 
-	@Override
-	public void onViewCreated(View view, @Nullable Bundle savedInstanceState) {
-		if (savedInstanceState != null) {
-			clicked = savedInstanceState.getBoolean(STATE_KEY_CLICKED);
-		}
-		if (clicked) {
-			setNextClicked();
-		}
-	}
-
-	@Override
-	public void onSaveInstanceState(@NonNull Bundle outState) {
-		super.onSaveInstanceState(outState);
-		outState.putBoolean(STATE_KEY_CLICKED, clicked);
-	}
-
-	@CallSuper
-	void setNextClicked() {
-		this.clicked = true;
-	}
-
 	@Override
 	public void onCreateOptionsMenu(Menu menu, MenuInflater inflater) {
 		inflater.inflate(R.menu.help_action, menu);
@@ -114,5 +89,4 @@ abstract class SetupFragment extends BaseFragment implements TextWatcher,
 	public void afterTextChanged(Editable editable) {
 		// noop
 	}
-
 }

briar-android/src/main/java/org/briarproject/briar/android/account/SetupViewModel.java

@@ -17,6 +17,8 @@ import javax.inject.Inject;
 
 import androidx.annotation.Nullable;
 import androidx.lifecycle.AndroidViewModel;
+import androidx.lifecycle.LiveData;
+import androidx.lifecycle.MutableLiveData;
 
 import static java.util.logging.Logger.getLogger;
 import static org.briarproject.briar.android.account.SetupViewModel.State.AUTHOR_NAME;
@@ -36,6 +38,8 @@ class SetupViewModel extends AndroidViewModel {
 	@Nullable
 	private String authorName, password;
 	private final MutableLiveEvent<State> state = new MutableLiveEvent<>();
+	private final MutableLiveData<Boolean> isCreatingAccount =
+			new MutableLiveData<>(false);
 
 	private final AccountManager accountManager;
 	private final Executor ioExecutor;
@@ -67,6 +71,10 @@ class SetupViewModel extends AndroidViewModel {
 		return state;
 	}
 
+	LiveData<Boolean> getIsCreatingAccount() {
+		return isCreatingAccount;
+	}
+
 	void setAuthorName(String authorName) {
 		this.authorName = authorName;
 		state.setEvent(SET_PASSWORD);
@@ -97,6 +105,7 @@ class SetupViewModel extends AndroidViewModel {
 	private void createAccount() {
 		if (authorName == null) throw new IllegalStateException();
 		if (password == null) throw new IllegalStateException();
+		isCreatingAccount.setValue(true);
 		ioExecutor.execute(() -> {
 			if (accountManager.createAccount(authorName, password)) {
 				LOG.info("Created account");

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

@@ -24,6 +24,10 @@ import org.briarproject.briar.android.blog.RssFeedImportActivity;
 import org.briarproject.briar.android.blog.RssFeedManageActivity;
 import org.briarproject.briar.android.blog.WriteBlogPostActivity;
 import org.briarproject.briar.android.contact.ContactListFragment;
+import org.briarproject.briar.android.contact.add.nearby.AddNearbyContactActivity;
+import org.briarproject.briar.android.contact.add.nearby.AddNearbyContactErrorFragment;
+import org.briarproject.briar.android.contact.add.nearby.AddNearbyContactFragment;
+import org.briarproject.briar.android.contact.add.nearby.AddNearbyContactIntroFragment;
 import org.briarproject.briar.android.contact.add.remote.AddContactActivity;
 import org.briarproject.briar.android.contact.add.remote.LinkExchangeFragment;
 import org.briarproject.briar.android.contact.add.remote.NicknameFragment;
@@ -39,10 +43,6 @@ import org.briarproject.briar.android.fragment.ScreenFilterDialogFragment;
 import org.briarproject.briar.android.introduction.ContactChooserFragment;
 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.KeyAgreementActivity;
-import org.briarproject.briar.android.keyagreement.KeyAgreementFragment;
 import org.briarproject.briar.android.login.ChangePasswordActivity;
 import org.briarproject.briar.android.login.OpenDatabaseFragment;
 import org.briarproject.briar.android.login.PasswordFragment;
@@ -122,9 +122,7 @@ public interface ActivityComponent {
 
 	void inject(PanicPreferencesActivity activity);
 
-	void inject(ContactExchangeActivity activity);
+	void inject(AddNearbyContactActivity activity);
-
-	void inject(KeyAgreementActivity activity);
 
 	void inject(ConversationActivity activity);
 
@@ -226,7 +224,9 @@ public interface ActivityComponent {
 
 	void inject(FeedFragment fragment);
 
-	void inject(KeyAgreementFragment fragment);
+	void inject(AddNearbyContactIntroFragment fragment);
+
+	void inject(AddNearbyContactFragment fragment);
 
 	void inject(LinkExchangeFragment fragment);
 
@@ -244,7 +244,7 @@ public interface ActivityComponent {
 
 	void inject(ScreenFilterDialogFragment fragment);
 
-	void inject(ContactExchangeErrorFragment fragment);
+	void inject(AddNearbyContactErrorFragment fragment);
 
 	void inject(AliasDialogFragment aliasDialogFragment);
 

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

@@ -9,9 +9,7 @@ public interface RequestCodes {
 	int REQUEST_WRITE_BLOG_POST = 5;
 	int REQUEST_SHARE_BLOG = 6;
 	int REQUEST_RINGTONE = 7;
-	int REQUEST_PERMISSION_CAMERA_LOCATION = 8;
 	int REQUEST_DOZE_WHITELISTING = 9;
-	int REQUEST_BLUETOOTH_DISCOVERABLE = 10;
 	int REQUEST_UNLOCK = 11;
 	int REQUEST_KEYGUARD_UNLOCK = 12;
 	int REQUEST_ATTACH_IMAGE = 13;

briar-android/src/main/java/org/briarproject/briar/android/attachment/AttachmentRetrieverImpl.java

@@ -28,9 +28,12 @@ import javax.inject.Inject;
 import androidx.lifecycle.LiveData;
 import androidx.lifecycle.MutableLiveData;
 
+import static java.util.Arrays.asList;
 import static java.util.Objects.requireNonNull;
+import static java.util.logging.Level.INFO;
 import static java.util.logging.Level.WARNING;
 import static java.util.logging.Logger.getLogger;
+import static org.briarproject.bramble.util.AndroidUtils.getSupportedImageContentTypes;
 import static org.briarproject.bramble.util.IoUtils.tryToClose;
 import static org.briarproject.bramble.util.LogUtils.logException;
 import static org.briarproject.briar.android.attachment.AttachmentItem.State.AVAILABLE;
@@ -86,7 +89,17 @@ class AttachmentRetrieverImpl implements AttachmentRetriever {
 		List<AttachmentHeader> headers = messageHeader.getAttachmentHeaders();
 		List<LiveData<AttachmentItem>> items = new ArrayList<>(headers.size());
 		boolean needsSize = headers.size() == 1;
+		List<String> supported = asList(getSupportedImageContentTypes());
 		for (AttachmentHeader h : headers) {
+			// Fail early if we don't support the content type
+			if (!supported.contains(h.getContentType())) {
+				if (LOG.isLoggable(INFO)) {
+					LOG.info("Unsupported content type " + h.getContentType());
+				}
+				AttachmentItem item = new AttachmentItem(h, "", ERROR);
+				items.add(new MutableLiveData<>(item));
+				continue;
+			}
 			// try cache for existing item live data
 			MutableLiveData<AttachmentItem> liveData =
 					itemsWithSize.get(h.getMessageId());

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

@@ -1,7 +1,6 @@
 package org.briarproject.briar.android.contact;
 
 import android.content.Context;
-import android.view.View;
 
 import org.briarproject.briar.android.util.BriarAdapter;
 
@@ -45,8 +44,4 @@ public abstract class BaseContactListAdapter<I extends ContactItem, VH extends C
 		return true;
 	}
 
-	public interface OnContactClickListener<I> {
-		void onItemClick(View view, I item);
-	}
-
 }

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

@@ -7,7 +7,6 @@ import android.widget.TextView;
 
 import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
 import org.briarproject.briar.R;
-import org.briarproject.briar.android.contact.BaseContactListAdapter.OnContactClickListener;
 
 import javax.annotation.Nullable;
 

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

@@ -7,7 +7,6 @@ import android.view.ViewGroup;
 import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
 import org.briarproject.bramble.api.nullsafety.NullSafety;
 import org.briarproject.briar.R;
-import org.briarproject.briar.android.contact.BaseContactListAdapter.OnContactClickListener;
 
 import androidx.recyclerview.widget.DiffUtil.ItemCallback;
 import androidx.recyclerview.widget.ListAdapter;
@@ -16,9 +15,6 @@ import androidx.recyclerview.widget.ListAdapter;
 public class ContactListAdapter extends
 		ListAdapter<ContactListItem, ContactListItemViewHolder> {
 
-	// TODO: using the click listener interface from BaseContactListAdapter on
-	// purpose here because it is entangled with ContactListItemViewHolder. At
-	// some point we probably want to change that.
 	protected final OnContactClickListener<ContactListItem> listener;
 
 	public ContactListAdapter(

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

@@ -15,12 +15,11 @@ 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.contact.BaseContactListAdapter.OnContactClickListener;
+import org.briarproject.briar.android.contact.add.nearby.AddNearbyContactActivity;
 import org.briarproject.briar.android.contact.add.remote.AddContactActivity;
 import org.briarproject.briar.android.contact.add.remote.PendingContactListActivity;
 import org.briarproject.briar.android.conversation.ConversationActivity;
 import org.briarproject.briar.android.fragment.BaseFragment;
-import org.briarproject.briar.android.keyagreement.ContactExchangeActivity;
 import org.briarproject.briar.android.util.BriarSnackbarBuilder;
 import org.briarproject.briar.android.view.BriarRecyclerView;
 
@@ -34,7 +33,6 @@ import io.github.kobakei.materialfabspeeddial.FabSpeedDial;
 import io.github.kobakei.materialfabspeeddial.FabSpeedDial.OnMenuItemClickListener;
 
 import static com.google.android.material.snackbar.BaseTransientBottomBar.LENGTH_INDEFINITE;
-import static org.briarproject.bramble.api.nullsafety.NullSafety.requireNonNull;
 import static org.briarproject.briar.android.conversation.ConversationActivity.CONTACT_ID;
 
 @MethodsNotNullByDefault
@@ -102,7 +100,6 @@ public class ContactListFragment extends BaseFragment
 				.observe(getViewLifecycleOwner(), result -> {
 					result.onError(this::handleException).onSuccess(items -> {
 						adapter.submitList(items);
-						if (requireNonNull(items).size() == 0) list.showData();
 					});
 				});
 		viewModel.getHasPendingContacts()
@@ -128,7 +125,8 @@ public class ContactListFragment extends BaseFragment
 		switch (itemId) {
 			case R.id.action_add_contact_nearby:
 				Intent intent =
-						new Intent(getContext(), ContactExchangeActivity.class);
+						new Intent(getContext(),
+								AddNearbyContactActivity.class);
 				startActivity(intent);
 				return;
 			case R.id.action_add_contact_remotely:

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

@@ -5,7 +5,6 @@ import android.widget.TextView;
 
 import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
 import org.briarproject.briar.R;
-import org.briarproject.briar.android.contact.BaseContactListAdapter.OnContactClickListener;
 
 import java.util.Locale;
 

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

@@ -3,70 +3,41 @@ package org.briarproject.briar.android.contact;
 import android.app.Application;
 
 import org.briarproject.bramble.api.connection.ConnectionRegistry;
-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.event.ContactAddedEvent;
-import org.briarproject.bramble.api.contact.event.ContactRemovedEvent;
 import org.briarproject.bramble.api.contact.event.PendingContactAddedEvent;
 import org.briarproject.bramble.api.contact.event.PendingContactRemovedEvent;
 import org.briarproject.bramble.api.db.DatabaseExecutor;
 import org.briarproject.bramble.api.db.DbException;
-import org.briarproject.bramble.api.db.Transaction;
 import org.briarproject.bramble.api.db.TransactionManager;
 import org.briarproject.bramble.api.event.Event;
 import org.briarproject.bramble.api.event.EventBus;
-import org.briarproject.bramble.api.event.EventListener;
 import org.briarproject.bramble.api.lifecycle.LifecycleManager;
 import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
-import org.briarproject.bramble.api.plugin.event.ContactConnectedEvent;
-import org.briarproject.bramble.api.plugin.event.ContactDisconnectedEvent;
 import org.briarproject.bramble.api.system.AndroidExecutor;
-import org.briarproject.briar.android.viewmodel.DbViewModel;
-import org.briarproject.briar.android.viewmodel.LiveResult;
 import org.briarproject.briar.api.android.AndroidNotificationManager;
-import org.briarproject.briar.api.avatar.event.AvatarUpdatedEvent;
-import org.briarproject.briar.api.client.MessageTracker;
 import org.briarproject.briar.api.conversation.ConversationManager;
-import org.briarproject.briar.api.conversation.ConversationMessageHeader;
-import org.briarproject.briar.api.conversation.event.ConversationMessageReceivedEvent;
-import org.briarproject.briar.api.identity.AuthorInfo;
 import org.briarproject.briar.api.identity.AuthorManager;
 
-import java.util.ArrayList;
-import java.util.Collections;
-import java.util.List;
 import java.util.concurrent.Executor;
 import java.util.logging.Logger;
 
 import javax.inject.Inject;
 
-import androidx.arch.core.util.Function;
 import androidx.lifecycle.LiveData;
 import androidx.lifecycle.MutableLiveData;
 
 import static java.util.logging.Level.WARNING;
 import static java.util.logging.Logger.getLogger;
-import static org.briarproject.bramble.util.LogUtils.logDuration;
 import static org.briarproject.bramble.util.LogUtils.logException;
-import static org.briarproject.bramble.util.LogUtils.now;
 
 @NotNullByDefault
-class ContactListViewModel extends DbViewModel implements EventListener {
+class ContactListViewModel extends ContactsViewModel {
 
 	private static final Logger LOG =
 			getLogger(ContactListViewModel.class.getName());
 
-	private final ContactManager contactManager;
-	private final AuthorManager authorManager;
-	private final ConversationManager conversationManager;
-	private final ConnectionRegistry connectionRegistry;
-	private final EventBus eventBus;
 	private final AndroidNotificationManager notificationManager;
 
-	private final MutableLiveData<LiveResult<List<ContactListItem>>>
-			contactListItems = new MutableLiveData<>();
-
 	private final MutableLiveData<Boolean> hasPendingContacts =
 			new MutableLiveData<>();
 
@@ -79,99 +50,25 @@ class ContactListViewModel extends DbViewModel implements EventListener {
 			ConversationManager conversationManager,
 			ConnectionRegistry connectionRegistry, EventBus eventBus,
 			AndroidNotificationManager notificationManager) {
-		super(application, dbExecutor, lifecycleManager, db, androidExecutor);
+		super(application, dbExecutor, lifecycleManager, db, androidExecutor,
-		this.contactManager = contactManager;
+				contactManager, authorManager, conversationManager,
-		this.authorManager = authorManager;
+				connectionRegistry, eventBus);
-		this.conversationManager = conversationManager;
-		this.connectionRegistry = connectionRegistry;
-		this.eventBus = eventBus;
 		this.notificationManager = notificationManager;
-		this.eventBus.addListener(this);
-	}
-
-	@Override
-	protected void onCleared() {
-		super.onCleared();
-		eventBus.removeListener(this);
-	}
-
-	void loadContacts() {
-		loadList(this::loadContacts, contactListItems::setValue);
-	}
-
-	private List<ContactListItem> loadContacts(Transaction txn)
-			throws DbException {
-		long start = now();
-		List<ContactListItem> contacts = new ArrayList<>();
-		for (Contact c : contactManager.getContacts(txn)) {
-			ContactId id = c.getId();
-			AuthorInfo authorInfo = authorManager.getAuthorInfo(txn, c);
-			MessageTracker.GroupCount count =
-					conversationManager.getGroupCount(txn, id);
-			boolean connected = connectionRegistry.isConnected(c.getId());
-			contacts.add(new ContactListItem(c, authorInfo, connected, count));
-		}
-		Collections.sort(contacts);
-		logDuration(LOG, "Full load", start);
-		return contacts;
 	}
 
 	@Override
 	public void eventOccurred(Event e) {
-		if (e instanceof ContactAddedEvent) {
+		super.eventOccurred(e);
-			LOG.info("Contact added, reloading");
+		if (e instanceof PendingContactAddedEvent ||
-			loadContacts();
-		} else if (e instanceof ContactConnectedEvent) {
-			updateItem(((ContactConnectedEvent) e).getContactId(),
-					item -> new ContactListItem(item, true), false);
-		} else if (e instanceof ContactDisconnectedEvent) {
-			updateItem(((ContactDisconnectedEvent) e).getContactId(),
-					item -> new ContactListItem(item, false), false);
-		} else if (e instanceof ContactRemovedEvent) {
-			LOG.info("Contact removed, removing item");
-			removeItem(((ContactRemovedEvent) e).getContactId());
-		} else if (e instanceof ConversationMessageReceivedEvent) {
-			LOG.info("Conversation message received, updating item");
-			ConversationMessageReceivedEvent<?> p =
-					(ConversationMessageReceivedEvent<?>) e;
-			ConversationMessageHeader h = p.getMessageHeader();
-			updateItem(p.getContactId(), item -> new ContactListItem(item, h),
-					true);
-		} else if (e instanceof PendingContactAddedEvent ||
 				e instanceof PendingContactRemovedEvent) {
 			checkForPendingContacts();
-		} else if (e instanceof AvatarUpdatedEvent) {
-			AvatarUpdatedEvent a = (AvatarUpdatedEvent) e;
-			updateItem(a.getContactId(), item -> new ContactListItem(item,
-					a.getAttachmentHeader()), false);
 		}
 	}
 
-	LiveData<LiveResult<List<ContactListItem>>> getContactListItems() {
-		return contactListItems;
-	}
-
 	LiveData<Boolean> getHasPendingContacts() {
 		return hasPendingContacts;
 	}
 
-	private void updateItem(ContactId c,
-			Function<ContactListItem, ContactListItem> replacer, boolean sort) {
-		List<ContactListItem> list = updateListItems(contactListItems,
-				itemToTest -> itemToTest.getContact().getId().equals(c),
-				replacer);
-		if (list == null) return;
-		if (sort) Collections.sort(list);
-		contactListItems.setValue(new LiveResult<>(list));
-	}
-
-	private void removeItem(ContactId c) {
-		List<ContactListItem> list = removeListItems(contactListItems,
-				itemToTest -> itemToTest.getContact().getId().equals(c));
-		if (list == null) return;
-		contactListItems.setValue(new LiveResult<>(list));
-	}
-
 	void checkForPendingContacts() {
 		runOnDbThread(() -> {
 			try {

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

@@ -0,0 +1,170 @@
+package org.briarproject.briar.android.contact;
+
+import android.app.Application;
+
+import org.briarproject.bramble.api.connection.ConnectionRegistry;
+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.event.ContactAddedEvent;
+import org.briarproject.bramble.api.contact.event.ContactRemovedEvent;
+import org.briarproject.bramble.api.db.DatabaseExecutor;
+import org.briarproject.bramble.api.db.DbException;
+import org.briarproject.bramble.api.db.Transaction;
+import org.briarproject.bramble.api.db.TransactionManager;
+import org.briarproject.bramble.api.event.Event;
+import org.briarproject.bramble.api.event.EventBus;
+import org.briarproject.bramble.api.event.EventListener;
+import org.briarproject.bramble.api.lifecycle.LifecycleManager;
+import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
+import org.briarproject.bramble.api.plugin.event.ContactConnectedEvent;
+import org.briarproject.bramble.api.plugin.event.ContactDisconnectedEvent;
+import org.briarproject.bramble.api.system.AndroidExecutor;
+import org.briarproject.briar.android.viewmodel.DbViewModel;
+import org.briarproject.briar.android.viewmodel.LiveResult;
+import org.briarproject.briar.api.avatar.event.AvatarUpdatedEvent;
+import org.briarproject.briar.api.client.MessageTracker;
+import org.briarproject.briar.api.conversation.ConversationManager;
+import org.briarproject.briar.api.conversation.ConversationMessageHeader;
+import org.briarproject.briar.api.conversation.event.ConversationMessageReceivedEvent;
+import org.briarproject.briar.api.identity.AuthorInfo;
+import org.briarproject.briar.api.identity.AuthorManager;
+
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.List;
+import java.util.concurrent.Executor;
+import java.util.logging.Logger;
+
+import javax.inject.Inject;
+
+import androidx.annotation.UiThread;
+import androidx.arch.core.util.Function;
+import androidx.lifecycle.LiveData;
+import androidx.lifecycle.MutableLiveData;
+
+import static java.util.logging.Logger.getLogger;
+import static org.briarproject.bramble.util.LogUtils.logDuration;
+import static org.briarproject.bramble.util.LogUtils.now;
+
+@NotNullByDefault
+public class ContactsViewModel extends DbViewModel implements EventListener {
+
+	private static final Logger LOG =
+			getLogger(ContactsViewModel.class.getName());
+
+	protected final ContactManager contactManager;
+	private final AuthorManager authorManager;
+	private final ConversationManager conversationManager;
+	private final ConnectionRegistry connectionRegistry;
+	private final EventBus eventBus;
+
+	private final MutableLiveData<LiveResult<List<ContactListItem>>>
+			contactListItems = new MutableLiveData<>();
+
+	@Inject
+	public ContactsViewModel(Application application,
+			@DatabaseExecutor Executor dbExecutor,
+			LifecycleManager lifecycleManager, TransactionManager db,
+			AndroidExecutor androidExecutor, ContactManager contactManager,
+			AuthorManager authorManager,
+			ConversationManager conversationManager,
+			ConnectionRegistry connectionRegistry, EventBus eventBus) {
+		super(application, dbExecutor, lifecycleManager, db, androidExecutor);
+		this.contactManager = contactManager;
+		this.authorManager = authorManager;
+		this.conversationManager = conversationManager;
+		this.connectionRegistry = connectionRegistry;
+		this.eventBus = eventBus;
+		this.eventBus.addListener(this);
+	}
+
+	@Override
+	protected void onCleared() {
+		super.onCleared();
+		eventBus.removeListener(this);
+	}
+
+	protected void loadContacts() {
+		loadList(this::loadContacts, contactListItems::setValue);
+	}
+
+	private List<ContactListItem> loadContacts(Transaction txn)
+			throws DbException {
+		long start = now();
+		List<ContactListItem> contacts = new ArrayList<>();
+		for (Contact c : contactManager.getContacts(txn)) {
+			ContactId id = c.getId();
+			if (!displayContact(id)) {
+				continue;
+			}
+			AuthorInfo authorInfo = authorManager.getAuthorInfo(txn, c);
+			MessageTracker.GroupCount count =
+					conversationManager.getGroupCount(txn, id);
+			boolean connected = connectionRegistry.isConnected(c.getId());
+			contacts.add(new ContactListItem(c, authorInfo, connected, count));
+		}
+		Collections.sort(contacts);
+		logDuration(LOG, "Full load", start);
+		return contacts;
+	}
+
+	/**
+	 * Override this method to display only a subset of contacts.
+	 */
+	protected boolean displayContact(ContactId contactId) {
+		return true;
+	}
+
+	@Override
+	public void eventOccurred(Event e) {
+		if (e instanceof ContactAddedEvent) {
+			LOG.info("Contact added, reloading");
+			loadContacts();
+		} else if (e instanceof ContactConnectedEvent) {
+			updateItem(((ContactConnectedEvent) e).getContactId(),
+					item -> new ContactListItem(item, true), false);
+		} else if (e instanceof ContactDisconnectedEvent) {
+			updateItem(((ContactDisconnectedEvent) e).getContactId(),
+					item -> new ContactListItem(item, false), false);
+		} else if (e instanceof ContactRemovedEvent) {
+			LOG.info("Contact removed, removing item");
+			removeItem(((ContactRemovedEvent) e).getContactId());
+		} else if (e instanceof ConversationMessageReceivedEvent) {
+			LOG.info("Conversation message received, updating item");
+			ConversationMessageReceivedEvent<?> p =
+					(ConversationMessageReceivedEvent<?>) e;
+			ConversationMessageHeader h = p.getMessageHeader();
+			updateItem(p.getContactId(), item -> new ContactListItem(item, h),
+					true);
+		} else if (e instanceof AvatarUpdatedEvent) {
+			AvatarUpdatedEvent a = (AvatarUpdatedEvent) e;
+			updateItem(a.getContactId(), item -> new ContactListItem(item,
+					a.getAttachmentHeader()), false);
+		}
+	}
+
+	public LiveData<LiveResult<List<ContactListItem>>> getContactListItems() {
+		return contactListItems;
+	}
+
+	@UiThread
+	private void updateItem(ContactId c,
+			Function<ContactListItem, ContactListItem> replacer, boolean sort) {
+		List<ContactListItem> list = updateListItems(contactListItems,
+				itemToTest -> itemToTest.getContact().getId().equals(c),
+				replacer);
+		if (list == null) return;
+		if (sort) Collections.sort(list);
+		contactListItems.setValue(new LiveResult<>(list));
+	}
+
+	@UiThread
+	private void removeItem(ContactId c) {
+		List<ContactListItem> list = removeListItems(contactListItems,
+				itemToTest -> itemToTest.getContact().getId().equals(c));
+		if (list == null) return;
+		contactListItems.setValue(new LiveResult<>(list));
+	}
+
+}

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

@@ -1,50 +0,0 @@
-package org.briarproject.briar.android.contact;
-
-import android.content.Context;
-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 LegacyContactListAdapter extends
-		BaseContactListAdapter<ContactListItem, ContactListItemViewHolder> {
-
-	public LegacyContactListAdapter(Context context,
-			OnContactClickListener<ContactListItem> listener) {
-		super(context, ContactListItem.class, listener);
-	}
-
-	@Override
-	public ContactListItemViewHolder onCreateViewHolder(ViewGroup viewGroup,
-			int i) {
-		View v = LayoutInflater.from(viewGroup.getContext()).inflate(
-				R.layout.list_item_contact, viewGroup, false);
-
-		return new ContactListItemViewHolder(v);
-	}
-
-	@Override
-	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;
-		}
-		if (c1.getTimestamp() != c2.getTimestamp()) {
-			return false;
-		}
-		return c1.isConnected() == c2.isConnected();
-	}
-
-	@Override
-	public int compare(ContactListItem c1, ContactListItem c2) {
-		return Long.compare(c2.getTimestamp(), c1.getTimestamp());
-	}
-
-}

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

@@ -0,0 +1,9 @@
+package org.briarproject.briar.android.contact;
+
+import android.view.View;
+
+public interface OnContactClickListener<I> {
+
+	void onItemClick(View view, I item);
+
+}

briar-android/src/main/java/org/briarproject/briar/android/contact/add/nearby/AddContactState.java

@@ -0,0 +1,76 @@
+package org.briarproject.briar.android.contact.add.nearby;
+
+import android.graphics.Bitmap;
+
+import org.briarproject.bramble.api.identity.Author;
+
+import androidx.annotation.Nullable;
+
+abstract class AddContactState {
+
+	static class KeyAgreementListening extends AddContactState {
+		final Bitmap qrCode;
+
+		KeyAgreementListening(Bitmap qrCode) {
+			this.qrCode = qrCode;
+		}
+	}
+
+	static class QrCodeScanned extends AddContactState {
+	}
+
+	static class KeyAgreementWaiting extends AddContactState {
+	}
+
+	static class KeyAgreementStarted extends AddContactState {
+	}
+
+	static class ContactExchangeStarted extends AddContactState {
+	}
+
+	static class ContactExchangeFinished extends AddContactState {
+		final ContactExchangeResult result;
+
+		ContactExchangeFinished(ContactExchangeResult result) {
+			this.result = result;
+		}
+	}
+
+	static class Failed extends AddContactState {
+		/**
+		 * Non-null if failed due to the scanned QR code version.
+		 * True if the app producing the code is too old.
+		 * False if the scanning app is too old.
+		 */
+		@Nullable
+		final Boolean qrCodeTooOld;
+
+		Failed(@Nullable Boolean qrCodeTooOld) {
+			this.qrCodeTooOld = qrCodeTooOld;
+		}
+
+		Failed() {
+			this(null);
+		}
+	}
+
+	abstract static class ContactExchangeResult {
+		static class Success extends ContactExchangeResult {
+			final Author remoteAuthor;
+
+			Success(Author remoteAuthor) {
+				this.remoteAuthor = remoteAuthor;
+			}
+		}
+
+		static class Error extends ContactExchangeResult {
+			@Nullable
+			final Author duplicateAuthor;
+
+			Error(@Nullable Author duplicateAuthor) {
+				this.duplicateAuthor = duplicateAuthor;
+			}
+		}
+	} // end ContactExchangeResult
+
+}

briar-android/src/main/java/org/briarproject/briar/android/contact/add/nearby/AddNearbyContactActivity.java

@@ -0,0 +1,226 @@
+package org.briarproject.briar.android.contact.add.nearby;
+
+import android.content.Intent;
+import android.os.Bundle;
+import android.view.MenuItem;
+import android.widget.Toast;
+
+import org.briarproject.bramble.api.identity.Author;
+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.contact.add.nearby.AddContactState.ContactExchangeFinished;
+import org.briarproject.briar.android.contact.add.nearby.AddContactState.ContactExchangeResult;
+import org.briarproject.briar.android.contact.add.nearby.AddContactState.Failed;
+import org.briarproject.briar.android.contact.add.nearby.AddNearbyContactViewModel.BluetoothDecision;
+import org.briarproject.briar.android.fragment.BaseFragment;
+import org.briarproject.briar.android.fragment.BaseFragment.BaseFragmentListener;
+import org.briarproject.briar.android.util.RequestBluetoothDiscoverable;
+
+import java.util.logging.Logger;
+
+import javax.annotation.Nullable;
+import javax.inject.Inject;
+
+import androidx.activity.result.ActivityResultLauncher;
+import androidx.activity.result.contract.ActivityResultContracts.RequestMultiplePermissions;
+import androidx.appcompat.widget.Toolbar;
+import androidx.fragment.app.FragmentManager;
+import androidx.lifecycle.ViewModelProvider;
+
+import static android.bluetooth.BluetoothAdapter.ACTION_REQUEST_DISCOVERABLE;
+import static android.content.Intent.FLAG_ACTIVITY_CLEAR_TOP;
+import static android.widget.Toast.LENGTH_LONG;
+import static java.util.Objects.requireNonNull;
+import static java.util.logging.Logger.getLogger;
+import static org.briarproject.briar.android.contact.add.nearby.AddNearbyContactViewModel.BluetoothDecision.ACCEPTED;
+import static org.briarproject.briar.android.contact.add.nearby.AddNearbyContactViewModel.BluetoothDecision.REFUSED;
+
+@MethodsNotNullByDefault
+@ParametersNotNullByDefault
+public class AddNearbyContactActivity extends BriarActivity
+		implements BaseFragmentListener {
+
+	private static final Logger LOG =
+			getLogger(AddNearbyContactActivity.class.getName());
+
+	@Inject
+	ViewModelProvider.Factory viewModelFactory;
+
+	private AddNearbyContactViewModel viewModel;
+	private AddNearbyContactPermissionManager permissionManager;
+
+	private final ActivityResultLauncher<String[]> permissionLauncher =
+			registerForActivityResult(new RequestMultiplePermissions(), r ->
+					permissionManager.onRequestPermissionResult(r,
+							viewModel::showQrCodeFragmentIfAllowed));
+	private final ActivityResultLauncher<Integer> bluetoothLauncher =
+			registerForActivityResult(new RequestBluetoothDiscoverable(),
+					this::onBluetoothDiscoverableResult);
+
+	@Override
+	public void injectActivity(ActivityComponent component) {
+		component.inject(this);
+		viewModel = new ViewModelProvider(this, viewModelFactory)
+				.get(AddNearbyContactViewModel.class);
+		permissionManager = new AddNearbyContactPermissionManager(this,
+				permissionLauncher::launch, viewModel.isBluetoothSupported());
+	}
+
+	@Override
+	public void onCreate(@Nullable Bundle state) {
+		super.onCreate(state);
+		setContentView(R.layout.activity_fragment_container_toolbar);
+		Toolbar toolbar = findViewById(R.id.toolbar);
+		setSupportActionBar(toolbar);
+		requireNonNull(getSupportActionBar()).setDisplayHomeAsUpEnabled(true);
+		if (state == null) {
+			showInitialFragment(AddNearbyContactIntroFragment.newInstance());
+		}
+		viewModel.getCheckPermissions().observeEvent(this, check ->
+				permissionManager.checkPermissions());
+		viewModel.getRequestBluetoothDiscoverable().observeEvent(this, r ->
+				requestBluetoothDiscoverable()); // never false
+		viewModel.getShowQrCodeFragment().observeEvent(this, show -> {
+			if (show) showQrCodeFragment();
+		});
+		requireNonNull(getSupportActionBar())
+				.setTitle(R.string.add_contact_title);
+		viewModel.getState()
+				.observe(this, this::onAddContactStateChanged);
+	}
+
+	@Override
+	public void onStart() {
+		super.onStart();
+		// Permissions may have been granted manually while we were stopped
+		permissionManager.resetPermissions();
+	}
+
+	@Override
+	protected void onPostResume() {
+		super.onPostResume();
+		viewModel.setIsActivityResumed(true);
+	}
+
+	@Override
+	protected void onPause() {
+		super.onPause();
+		viewModel.setIsActivityResumed(false);
+	}
+
+	private void onBluetoothDiscoverableResult(boolean discoverable) {
+		if (discoverable) {
+			LOG.info("Bluetooth discoverability was accepted");
+			viewModel.setBluetoothDecision(ACCEPTED);
+		} else {
+			LOG.info("Bluetooth discoverability was refused");
+			viewModel.setBluetoothDecision(REFUSED);
+		}
+	}
+
+	@Override
+	public boolean onOptionsItemSelected(MenuItem item) {
+		if (item.getItemId() == android.R.id.home) {
+			onBackPressed();
+			return true;
+		}
+		return super.onOptionsItemSelected(item);
+	}
+
+	@Override
+	public void onBackPressed() {
+		if (viewModel.getState().getValue() instanceof Failed) {
+			// re-create this activity when going back in failed state
+			Intent i = new Intent(this, AddNearbyContactActivity.class);
+			i.setFlags(FLAG_ACTIVITY_CLEAR_TOP);
+			startActivity(i);
+		} else {
+			super.onBackPressed();
+		}
+	}
+
+	private void requestBluetoothDiscoverable() {
+		if (!viewModel.isBluetoothSupported()) {
+			viewModel.setBluetoothDecision(BluetoothDecision.NO_ADAPTER);
+		} else {
+			Intent i = new Intent(ACTION_REQUEST_DISCOVERABLE);
+			if (i.resolveActivity(getPackageManager()) != null) {
+				LOG.info("Asking for Bluetooth discoverability");
+				viewModel.setBluetoothDecision(BluetoothDecision.WAITING);
+				bluetoothLauncher.launch(120); // 2min discoverable
+			} else {
+				viewModel.setBluetoothDecision(BluetoothDecision.NO_ADAPTER);
+			}
+		}
+	}
+
+	private void showQrCodeFragment() {
+		// FIXME #824
+		FragmentManager fm = getSupportFragmentManager();
+		if (fm.findFragmentByTag(AddNearbyContactFragment.TAG) == null) {
+			BaseFragment f = AddNearbyContactFragment.newInstance();
+			fm.beginTransaction()
+					.replace(R.id.fragmentContainer, f, f.getUniqueTag())
+					.addToBackStack(f.getUniqueTag())
+					.commit();
+		}
+	}
+
+	private void onAddContactStateChanged(AddContactState state) {
+		if (state instanceof ContactExchangeFinished) {
+			ContactExchangeResult result =
+					((ContactExchangeFinished) state).result;
+			onContactExchangeResult(result);
+		} else if (state instanceof Failed) {
+			Boolean qrCodeTooOld = ((Failed) state).qrCodeTooOld;
+			onAddingContactFailed(qrCodeTooOld);
+		}
+	}
+
+	private void onContactExchangeResult(ContactExchangeResult result) {
+		if (result instanceof ContactExchangeResult.Success) {
+			Author remoteAuthor =
+					((ContactExchangeResult.Success) result).remoteAuthor;
+			String contactName = remoteAuthor.getName();
+			String text = getString(R.string.contact_added_toast, contactName);
+			Toast.makeText(this, text, LENGTH_LONG).show();
+			supportFinishAfterTransition();
+		} else if (result instanceof ContactExchangeResult.Error) {
+			Author duplicateAuthor =
+					((ContactExchangeResult.Error) result).duplicateAuthor;
+			if (duplicateAuthor == null) {
+				showErrorFragment();
+			} else {
+				String contactName = duplicateAuthor.getName();
+				String text =
+						getString(R.string.contact_already_exists, contactName);
+				Toast.makeText(this, text, LENGTH_LONG).show();
+				supportFinishAfterTransition();
+			}
+		} else throw new AssertionError();
+	}
+
+	private void onAddingContactFailed(@Nullable Boolean qrCodeTooOld) {
+		if (qrCodeTooOld == null) {
+			showErrorFragment();
+		} else {
+			String msg;
+			if (qrCodeTooOld) {
+				msg = getString(R.string.qr_code_too_old,
+						getString(R.string.app_name));
+			} else {
+				msg = getString(R.string.qr_code_too_new,
+						getString(R.string.app_name));
+			}
+			showNextFragment(AddNearbyContactErrorFragment.newInstance(msg));
+		}
+	}
+
+	private void showErrorFragment() {
+		showNextFragment(new AddNearbyContactErrorFragment());
+	}
+
+}

briar-android/src/main/java/org/briarproject/briar/android/contact/add/nearby/AddNearbyContactErrorFragment.java

@@ -1,4 +1,4 @@
-package org.briarproject.briar.android.keyagreement;
+package org.briarproject.briar.android.contact.add.nearby;
 
 import android.content.Intent;
 import android.os.Bundle;
@@ -24,14 +24,14 @@ import static org.briarproject.briar.android.util.UiUtils.onSingleLinkClick;
 
 @MethodsNotNullByDefault
 @ParametersNotNullByDefault
-public class ContactExchangeErrorFragment extends BaseFragment {
+public class AddNearbyContactErrorFragment extends BaseFragment {
 
 	public static final String TAG =
-			ContactExchangeErrorFragment.class.getName();
+			AddNearbyContactErrorFragment.class.getName();
 	private static final String ERROR_MSG = "errorMessage";
 
-	public static ContactExchangeErrorFragment newInstance(String errorMsg) {
+	public static AddNearbyContactErrorFragment newInstance(String errorMsg) {
-		ContactExchangeErrorFragment f = new ContactExchangeErrorFragment();
+		AddNearbyContactErrorFragment f = new AddNearbyContactErrorFragment();
 		Bundle args = new Bundle();
 		args.putString(ERROR_MSG, errorMsg);
 		f.setArguments(args);
@@ -72,7 +72,7 @@ public class ContactExchangeErrorFragment extends BaseFragment {
 		tryAgain.setOnClickListener(view -> {
 			// Recreate the activity so we return to the intro fragment
 			FragmentActivity activity = requireActivity();
-			Intent i = new Intent(activity, ContactExchangeActivity.class);
+			Intent i = new Intent(activity, AddNearbyContactActivity.class);
 			i.setFlags(FLAG_ACTIVITY_CLEAR_TOP);
 			activity.startActivity(i);
 		});

briar-android/src/main/java/org/briarproject/briar/android/contact/add/nearby/AddNearbyContactFragment.java

@@ -0,0 +1,202 @@
+package org.briarproject.briar.android.contact.add.nearby;
+
+import android.graphics.Bitmap;
+import android.os.Bundle;
+import android.view.LayoutInflater;
+import android.view.View;
+import android.view.ViewGroup;
+import android.widget.LinearLayout;
+import android.widget.LinearLayout.LayoutParams;
+import android.widget.TextView;
+import android.widget.Toast;
+
+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.contact.add.nearby.AddContactState.ContactExchangeStarted;
+import org.briarproject.briar.android.contact.add.nearby.AddContactState.Failed;
+import org.briarproject.briar.android.contact.add.nearby.AddContactState.KeyAgreementStarted;
+import org.briarproject.briar.android.contact.add.nearby.AddContactState.KeyAgreementWaiting;
+import org.briarproject.briar.android.contact.add.nearby.AddContactState.QrCodeScanned;
+import org.briarproject.briar.android.fragment.BaseFragment;
+import org.briarproject.briar.android.view.QrCodeView;
+
+import java.util.logging.Logger;
+
+import javax.annotation.Nullable;
+import javax.inject.Inject;
+
+import androidx.annotation.UiThread;
+import androidx.lifecycle.ViewModelProvider;
+
+import static android.content.pm.ActivityInfo.SCREEN_ORIENTATION_NOSENSOR;
+import static android.content.pm.ActivityInfo.SCREEN_ORIENTATION_UNSPECIFIED;
+import static android.view.View.INVISIBLE;
+import static android.view.View.VISIBLE;
+import static android.view.ViewGroup.LayoutParams.MATCH_PARENT;
+import static android.widget.LinearLayout.HORIZONTAL;
+import static android.widget.Toast.LENGTH_LONG;
+import static java.util.logging.Level.WARNING;
+import static org.briarproject.bramble.util.LogUtils.logException;
+
+@MethodsNotNullByDefault
+@ParametersNotNullByDefault
+public class AddNearbyContactFragment extends BaseFragment
+		implements QrCodeView.FullscreenListener {
+
+	static final String TAG = AddNearbyContactFragment.class.getName();
+
+	private static final Logger LOG = Logger.getLogger(TAG);
+
+	@Inject
+	ViewModelProvider.Factory viewModelFactory;
+
+	private AddNearbyContactViewModel viewModel;
+	private CameraView cameraView;
+	private LinearLayout cameraOverlay;
+	private View statusView;
+	private QrCodeView qrCodeView;
+	private TextView status;
+
+	public static AddNearbyContactFragment newInstance() {
+		Bundle args = new Bundle();
+		AddNearbyContactFragment fragment = new AddNearbyContactFragment();
+		fragment.setArguments(args);
+		return fragment;
+	}
+
+	@Override
+	public void injectFragment(ActivityComponent component) {
+		component.inject(this);
+		viewModel = new ViewModelProvider(requireActivity(), viewModelFactory)
+				.get(AddNearbyContactViewModel.class);
+	}
+
+	@Nullable
+	@Override
+	public View onCreateView(LayoutInflater inflater,
+			@Nullable ViewGroup container,
+			@Nullable Bundle savedInstanceState) {
+		return inflater.inflate(R.layout.fragment_keyagreement_qr, container,
+				false);
+	}
+
+	@Override
+	public void onViewCreated(View view, @Nullable Bundle savedInstanceState) {
+		super.onViewCreated(view, savedInstanceState);
+		cameraView = view.findViewById(R.id.camera_view);
+		cameraOverlay = view.findViewById(R.id.camera_overlay);
+		statusView = view.findViewById(R.id.status_container);
+		status = view.findViewById(R.id.connect_status);
+		qrCodeView = view.findViewById(R.id.qr_code_view);
+		qrCodeView.setFullscreenListener(this);
+
+		viewModel.getState().observe(getViewLifecycleOwner(),
+				this::onAddContactStateChanged);
+	}
+
+	@Override
+	public void onActivityCreated(@Nullable Bundle savedInstanceState) {
+		super.onActivityCreated(savedInstanceState);
+		requireActivity().setRequestedOrientation(SCREEN_ORIENTATION_NOSENSOR);
+		cameraView.setPreviewConsumer(viewModel.qrCodeDecoder);
+	}
+
+	@Override
+	public void onStart() {
+		super.onStart();
+		try {
+			cameraView.start();
+		} catch (CameraException e) {
+			logCameraExceptionAndFinish(e);
+		}
+	}
+
+	@Override
+	public void onStop() {
+		super.onStop();
+		try {
+			cameraView.stop();
+		} catch (CameraException e) {
+			logCameraExceptionAndFinish(e);
+		}
+	}
+
+	@Override
+	public void onDestroy() {
+		requireActivity()
+				.setRequestedOrientation(SCREEN_ORIENTATION_UNSPECIFIED);
+		super.onDestroy();
+	}
+
+	@Override
+	public void setFullscreen(boolean fullscreen) {
+		LinearLayout.LayoutParams statusParams, qrCodeParams;
+		if (fullscreen) {
+			// Grow the QR code view to fill its parent
+			statusParams = new LayoutParams(0, 0, 0f);
+			qrCodeParams = new LayoutParams(MATCH_PARENT, MATCH_PARENT, 1f);
+		} else {
+			// Shrink the QR code view to fill half its parent
+			if (cameraOverlay.getOrientation() == HORIZONTAL) {
+				statusParams = new LayoutParams(0, MATCH_PARENT, 1f);
+				qrCodeParams = new LayoutParams(0, MATCH_PARENT, 1f);
+			} else {
+				statusParams = new LayoutParams(MATCH_PARENT, 0, 1f);
+				qrCodeParams = new LayoutParams(MATCH_PARENT, 0, 1f);
+			}
+		}
+		statusView.setLayoutParams(statusParams);
+		qrCodeView.setLayoutParams(qrCodeParams);
+		cameraOverlay.invalidate();
+	}
+
+	@UiThread
+	private void onAddContactStateChanged(AddContactState state) {
+		if (state instanceof AddContactState.KeyAgreementListening) {
+			Bitmap qrCode =
+					((AddContactState.KeyAgreementListening) state).qrCode;
+			qrCodeView.setQrCode(qrCode);
+		} else if (state instanceof QrCodeScanned) {
+			try {
+				cameraView.stop();
+			} catch (CameraException e) {
+				logCameraExceptionAndFinish(e);
+			}
+			cameraView.setVisibility(INVISIBLE);
+			statusView.setVisibility(VISIBLE);
+			status.setText(R.string.connecting_to_device);
+		} else if (state instanceof KeyAgreementWaiting) {
+			status.setText(R.string.waiting_for_contact_to_scan);
+		} else if (state instanceof KeyAgreementStarted) {
+			qrCodeView.setVisibility(INVISIBLE);
+			status.setText(R.string.authenticating_with_device);
+		} else if (state instanceof ContactExchangeStarted) {
+			status.setText(R.string.exchanging_contact_details);
+		} else if (state instanceof Failed) {
+			// the activity will replace this fragment with an error fragment
+			statusView.setVisibility(INVISIBLE);
+			cameraView.setVisibility(INVISIBLE);
+		}
+	}
+
+	@Override
+	public String getUniqueTag() {
+		return TAG;
+	}
+
+	@UiThread
+	private void logCameraExceptionAndFinish(CameraException e) {
+		logException(LOG, WARNING, e);
+		Toast.makeText(getActivity(), R.string.camera_error,
+				LENGTH_LONG).show();
+		finish();
+	}
+
+	@Override
+	protected void finish() {
+		requireActivity().getSupportFragmentManager().popBackStack();
+	}
+
+}

briar-android/src/main/java/org/briarproject/briar/android/contact/add/nearby/AddNearbyContactIntroFragment.java

@@ -1,6 +1,5 @@
-package org.briarproject.briar.android.keyagreement;
+package org.briarproject.briar.android.contact.add.nearby;
 
-import android.content.Context;
 import android.os.Bundle;
 import android.view.LayoutInflater;
 import android.view.View;
@@ -10,43 +9,42 @@ import android.widget.ScrollView;
 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 javax.annotation.Nullable;
+import javax.inject.Inject;
+
+import androidx.lifecycle.ViewModelProvider;
 
 import static android.view.View.FOCUS_DOWN;
 
 @MethodsNotNullByDefault
 @ParametersNotNullByDefault
-public class IntroFragment extends BaseFragment {
+public class AddNearbyContactIntroFragment extends BaseFragment {
 
-	interface IntroScreenSeenListener {
+	public static final String TAG = AddNearbyContactIntroFragment.class.getName();
-		void showNextScreen();
-	}
 
-	public static final String TAG = IntroFragment.class.getName();
+	@Inject
+	ViewModelProvider.Factory viewModelFactory;
+
+	private AddNearbyContactViewModel viewModel;
 
-	private IntroScreenSeenListener screenSeenListener;
 	private ScrollView scrollView;
 
-	public static IntroFragment newInstance() {
+	public static AddNearbyContactIntroFragment newInstance() {
-
 		Bundle args = new Bundle();
-
+		AddNearbyContactIntroFragment
-		IntroFragment fragment = new IntroFragment();
+				fragment = new AddNearbyContactIntroFragment();
 		fragment.setArguments(args);
 		return fragment;
 	}
 
 	@Override
-	public void onAttach(Context context) {
+	public void injectFragment(ActivityComponent component) {
-		super.onAttach(context);
+		component.inject(this);
-		screenSeenListener = (IntroScreenSeenListener) context;
+		viewModel = new ViewModelProvider(requireActivity(), viewModelFactory)
-	}
+				.get(AddNearbyContactViewModel.class);
-
-	@Override
-	public String getUniqueTag() {
-		return TAG;
 	}
 
 	@Nullable
@@ -59,7 +57,7 @@ public class IntroFragment extends BaseFragment {
 				false);
 		scrollView = v.findViewById(R.id.scrollView);
 		View button = v.findViewById(R.id.continueButton);
-		button.setOnClickListener(view -> screenSeenListener.showNextScreen());
+		button.setOnClickListener(view -> viewModel.onContinueClicked());
 		return v;
 	}
 
@@ -69,4 +67,9 @@ public class IntroFragment extends BaseFragment {
 		scrollView.post(() -> scrollView.fullScroll(FOCUS_DOWN));
 	}
 
+	@Override
+	public String getUniqueTag() {
+		return TAG;
+	}
+
 }

briar-android/src/main/java/org/briarproject/briar/android/contact/add/nearby/AddNearbyContactModule.java

@@ -1,4 +1,4 @@
-package org.briarproject.briar.android.keyagreement;
+package org.briarproject.briar.android.contact.add.nearby;
 
 import org.briarproject.briar.android.viewmodel.ViewModelKey;
 
@@ -8,12 +8,12 @@ import dagger.Module;
 import dagger.multibindings.IntoMap;
 
 @Module
-public abstract class ContactExchangeModule {
+public abstract class AddNearbyContactModule {
 
 	@Binds
 	@IntoMap
-	@ViewModelKey(ContactExchangeViewModel.class)
+	@ViewModelKey(AddNearbyContactViewModel.class)
 	abstract ViewModel bindContactExchangeViewModel(
-			ContactExchangeViewModel contactExchangeViewModel);
+			AddNearbyContactViewModel addNearbyContactViewModel);
 
 }

briar-android/src/main/java/org/briarproject/briar/android/contact/add/nearby/AddNearbyContactPermissionManager.java

@@ -0,0 +1,168 @@
+package org.briarproject.briar.android.contact.add.nearby;
+
+import android.content.Context;
+
+import org.briarproject.briar.R;
+import org.briarproject.briar.android.activity.BaseActivity;
+
+import java.util.Map;
+
+import androidx.annotation.StringRes;
+import androidx.appcompat.app.AlertDialog;
+import androidx.core.util.Consumer;
+
+import static android.Manifest.permission.ACCESS_FINE_LOCATION;
+import static android.Manifest.permission.CAMERA;
+import static android.content.pm.PackageManager.PERMISSION_GRANTED;
+import static android.os.Build.VERSION.SDK_INT;
+import static androidx.core.app.ActivityCompat.shouldShowRequestPermissionRationale;
+import static androidx.core.content.ContextCompat.checkSelfPermission;
+import static org.briarproject.briar.android.util.UiUtils.getGoToSettingsListener;
+
+class AddNearbyContactPermissionManager {
+
+	private enum Permission {
+		UNKNOWN, GRANTED, SHOW_RATIONALE, PERMANENTLY_DENIED
+	}
+
+	private Permission cameraPermission = Permission.UNKNOWN;
+	private Permission locationPermission = Permission.UNKNOWN;
+
+	private final BaseActivity ctx;
+	private final Consumer<String[]> requestPermissions;
+	private final boolean isBluetoothSupported;
+
+	AddNearbyContactPermissionManager(BaseActivity ctx,
+			Consumer<String[]> requestPermissions,
+			boolean isBluetoothSupported) {
+		this.ctx = ctx;
+		this.requestPermissions = requestPermissions;
+		this.isBluetoothSupported = isBluetoothSupported;
+	}
+
+	void resetPermissions() {
+		cameraPermission = Permission.UNKNOWN;
+		locationPermission = Permission.UNKNOWN;
+	}
+
+	static boolean areEssentialPermissionsGranted(Context ctx,
+			boolean isBluetoothSupported) {
+		int ok = PERMISSION_GRANTED;
+		return checkSelfPermission(ctx, CAMERA) == ok &&
+				(SDK_INT < 23 ||
+						checkSelfPermission(ctx, ACCESS_FINE_LOCATION) == ok ||
+						!isBluetoothSupported);
+	}
+
+	boolean areEssentialPermissionsGranted() {
+		return cameraPermission == Permission.GRANTED &&
+				(SDK_INT < 23 || locationPermission == Permission.GRANTED ||
+						!isBluetoothSupported);
+	}
+
+	boolean checkPermissions() {
+		if (areEssentialPermissionsGranted()) return true;
+		// If an essential permission has been permanently denied, ask the
+		// user to change the setting
+		if (cameraPermission == Permission.PERMANENTLY_DENIED) {
+			showDenialDialog(R.string.permission_camera_title,
+					R.string.permission_camera_denied_body);
+			return false;
+		}
+		if (isBluetoothSupported &&
+				locationPermission == Permission.PERMANENTLY_DENIED) {
+			showDenialDialog(R.string.permission_location_title,
+					R.string.permission_location_denied_body);
+			return false;
+		}
+		// Should we show the rationale for one or both permissions?
+		if (cameraPermission == Permission.SHOW_RATIONALE &&
+				locationPermission == Permission.SHOW_RATIONALE) {
+			showRationale(R.string.permission_camera_location_title,
+					R.string.permission_camera_location_request_body);
+		} else if (cameraPermission == Permission.SHOW_RATIONALE) {
+			showRationale(R.string.permission_camera_title,
+					R.string.permission_camera_request_body);
+		} else if (locationPermission == Permission.SHOW_RATIONALE) {
+			showRationale(R.string.permission_location_title,
+					R.string.permission_location_request_body);
+		} else {
+			requestPermissions();
+		}
+		return false;
+	}
+
+	private void showDenialDialog(@StringRes int title, @StringRes int body) {
+		AlertDialog.Builder builder =
+				new AlertDialog.Builder(ctx, R.style.BriarDialogTheme);
+		builder.setTitle(title);
+		builder.setMessage(body);
+		builder.setPositiveButton(R.string.ok, getGoToSettingsListener(ctx));
+		builder.setNegativeButton(R.string.cancel,
+				(dialog, which) -> ctx.supportFinishAfterTransition());
+		builder.show();
+	}
+
+	private void showRationale(@StringRes int title, @StringRes int body) {
+		AlertDialog.Builder builder =
+				new AlertDialog.Builder(ctx, R.style.BriarDialogTheme);
+		builder.setTitle(title);
+		builder.setMessage(body);
+		builder.setNeutralButton(R.string.continue_button,
+				(dialog, which) -> requestPermissions());
+		builder.show();
+	}
+
+	private void requestPermissions() {
+		String[] permissions;
+		if (isBluetoothSupported) {
+			permissions = new String[] {CAMERA, ACCESS_FINE_LOCATION};
+		} else {
+			permissions = new String[] {CAMERA};
+		}
+		requestPermissions.accept(permissions);
+	}
+
+	void onRequestPermissionResult(Map<String, Boolean> result,
+			Runnable onPermissionsGranted) {
+		if (gotPermission(CAMERA, result)) {
+			cameraPermission = Permission.GRANTED;
+		} else if (shouldShowRationale(CAMERA)) {
+			cameraPermission = Permission.SHOW_RATIONALE;
+		} else {
+			cameraPermission = Permission.PERMANENTLY_DENIED;
+		}
+		if (isBluetoothSupported) {
+			if (gotPermission(ACCESS_FINE_LOCATION, result)) {
+				locationPermission = Permission.GRANTED;
+			} else if (shouldShowRationale(ACCESS_FINE_LOCATION)) {
+				locationPermission = Permission.SHOW_RATIONALE;
+			} else {
+				locationPermission = Permission.PERMANENTLY_DENIED;
+			}
+		}
+		// If a permission dialog has been shown, showing the QR code fragment
+		// on this call path would cause a crash due to
+		// https://code.google.com/p/android/issues/detail?id=190966.
+		// In that case the isResumed flag prevents the fragment from being
+		// shown here, and showQrCodeFragmentIfAllowed() will be called again
+		// from onPostResume().
+		if (checkPermissions()) onPermissionsGranted.run();
+	}
+
+	private boolean gotPermission(String permission,
+			Map<String, Boolean> result) {
+		Boolean permissionResult = result.get(permission);
+		return permissionResult == null ?
+				isGranted(permission) : permissionResult;
+	}
+
+	private boolean isGranted(String permission) {
+		return checkSelfPermission(ctx, permission) == PERMISSION_GRANTED;
+	}
+
+	private boolean shouldShowRationale(String permission) {
+		return shouldShowRequestPermissionRationale(ctx, permission);
+	}
+
+}

briar-android/src/main/java/org/briarproject/briar/android/contact/add/nearby/AddNearbyContactViewModel.java

@@ -0,0 +1,520 @@
+package org.briarproject.briar.android.contact.add.nearby;
+
+import android.app.Application;
+import android.bluetooth.BluetoothAdapter;
+import android.content.BroadcastReceiver;
+import android.content.Context;
+import android.content.Intent;
+import android.content.IntentFilter;
+import android.graphics.Bitmap;
+import android.util.DisplayMetrics;
+import android.widget.Toast;
+
+import com.google.zxing.Result;
+
+import org.briarproject.bramble.api.UnsupportedVersionException;
+import org.briarproject.bramble.api.connection.ConnectionManager;
+import org.briarproject.bramble.api.contact.Contact;
+import org.briarproject.bramble.api.contact.ContactExchangeManager;
+import org.briarproject.bramble.api.crypto.SecretKey;
+import org.briarproject.bramble.api.db.ContactExistsException;
+import org.briarproject.bramble.api.db.DbException;
+import org.briarproject.bramble.api.event.Event;
+import org.briarproject.bramble.api.event.EventBus;
+import org.briarproject.bramble.api.event.EventListener;
+import org.briarproject.bramble.api.keyagreement.KeyAgreementResult;
+import org.briarproject.bramble.api.keyagreement.KeyAgreementTask;
+import org.briarproject.bramble.api.keyagreement.Payload;
+import org.briarproject.bramble.api.keyagreement.PayloadEncoder;
+import org.briarproject.bramble.api.keyagreement.PayloadParser;
+import org.briarproject.bramble.api.keyagreement.event.KeyAgreementAbortedEvent;
+import org.briarproject.bramble.api.keyagreement.event.KeyAgreementFailedEvent;
+import org.briarproject.bramble.api.keyagreement.event.KeyAgreementFinishedEvent;
+import org.briarproject.bramble.api.keyagreement.event.KeyAgreementListeningEvent;
+import org.briarproject.bramble.api.keyagreement.event.KeyAgreementStartedEvent;
+import org.briarproject.bramble.api.keyagreement.event.KeyAgreementWaitingEvent;
+import org.briarproject.bramble.api.lifecycle.IoExecutor;
+import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
+import org.briarproject.bramble.api.plugin.BluetoothConstants;
+import org.briarproject.bramble.api.plugin.LanTcpConstants;
+import org.briarproject.bramble.api.plugin.Plugin;
+import org.briarproject.bramble.api.plugin.Plugin.State;
+import org.briarproject.bramble.api.plugin.PluginManager;
+import org.briarproject.bramble.api.plugin.TransportId;
+import org.briarproject.bramble.api.plugin.duplex.DuplexTransportConnection;
+import org.briarproject.bramble.api.plugin.event.TransportStateEvent;
+import org.briarproject.bramble.api.system.AndroidExecutor;
+import org.briarproject.briar.R;
+import org.briarproject.briar.android.contact.add.nearby.AddContactState.ContactExchangeFinished;
+import org.briarproject.briar.android.contact.add.nearby.AddContactState.ContactExchangeResult.Error;
+import org.briarproject.briar.android.contact.add.nearby.AddContactState.ContactExchangeResult.Success;
+import org.briarproject.briar.android.contact.add.nearby.AddContactState.ContactExchangeStarted;
+import org.briarproject.briar.android.contact.add.nearby.AddContactState.KeyAgreementListening;
+import org.briarproject.briar.android.contact.add.nearby.AddContactState.KeyAgreementStarted;
+import org.briarproject.briar.android.contact.add.nearby.AddContactState.KeyAgreementWaiting;
+import org.briarproject.briar.android.viewmodel.LiveEvent;
+import org.briarproject.briar.android.viewmodel.MutableLiveEvent;
+
+import java.io.IOException;
+import java.nio.charset.Charset;
+import java.util.concurrent.Executor;
+import java.util.logging.Logger;
+
+import javax.inject.Inject;
+import javax.inject.Provider;
+
+import androidx.annotation.Nullable;
+import androidx.annotation.UiThread;
+import androidx.lifecycle.AndroidViewModel;
+import androidx.lifecycle.LiveData;
+import androidx.lifecycle.MutableLiveData;
+
+import static android.bluetooth.BluetoothAdapter.ACTION_SCAN_MODE_CHANGED;
+import static android.bluetooth.BluetoothAdapter.EXTRA_SCAN_MODE;
+import static android.bluetooth.BluetoothAdapter.SCAN_MODE_CONNECTABLE_DISCOVERABLE;
+import static android.widget.Toast.LENGTH_LONG;
+import static java.util.Objects.requireNonNull;
+import static java.util.logging.Level.INFO;
+import static java.util.logging.Level.WARNING;
+import static java.util.logging.Logger.getLogger;
+import static org.briarproject.bramble.api.plugin.Plugin.State.ACTIVE;
+import static org.briarproject.bramble.api.plugin.Plugin.State.DISABLED;
+import static org.briarproject.bramble.api.plugin.Plugin.State.INACTIVE;
+import static org.briarproject.bramble.api.plugin.Plugin.State.STARTING_STOPPING;
+import static org.briarproject.bramble.util.LogUtils.logException;
+import static org.briarproject.briar.android.contact.add.nearby.AddNearbyContactPermissionManager.areEssentialPermissionsGranted;
+import static org.briarproject.briar.android.contact.add.nearby.AddNearbyContactViewModel.BluetoothDecision.REFUSED;
+import static org.briarproject.briar.android.contact.add.nearby.AddNearbyContactViewModel.BluetoothDecision.UNKNOWN;
+
+@NotNullByDefault
+class AddNearbyContactViewModel extends AndroidViewModel
+		implements EventListener, QrCodeDecoder.ResultCallback {
+
+	private static final Logger LOG =
+			getLogger(AddNearbyContactViewModel.class.getName());
+
+	enum BluetoothDecision {
+		/**
+		 * We haven't asked the user about Bluetooth discoverability.
+		 */
+		UNKNOWN,
+
+		/**
+		 * The device doesn't have a Bluetooth adapter.
+		 */
+		NO_ADAPTER,
+
+		/**
+		 * We're waiting for the user to accept or refuse discoverability.
+		 */
+		WAITING,
+
+		/**
+		 * The user has accepted discoverability.
+		 */
+		ACCEPTED,
+
+		/**
+		 * The user has refused discoverability.
+		 */
+		REFUSED
+	}
+
+	@SuppressWarnings("CharsetObjectCanBeUsed") // Requires minSdkVersion >= 19
+	private static final Charset ISO_8859_1 = Charset.forName("ISO-8859-1");
+
+	private final EventBus eventBus;
+	private final AndroidExecutor androidExecutor;
+	private final Executor ioExecutor;
+	private final PluginManager pluginManager;
+	private final PayloadEncoder payloadEncoder;
+	private final PayloadParser payloadParser;
+	private final Provider<KeyAgreementTask> keyAgreementTaskProvider;
+	private final ContactExchangeManager contactExchangeManager;
+	private final ConnectionManager connectionManager;
+
+	private final MutableLiveEvent<Boolean> checkPermissions =
+			new MutableLiveEvent<>();
+	private final MutableLiveEvent<Boolean> requestBluetoothDiscoverable =
+			new MutableLiveEvent<>();
+	private final MutableLiveEvent<Boolean> showQrCodeFragment =
+			new MutableLiveEvent<>();
+	private final MutableLiveData<AddContactState> state =
+			new MutableLiveData<>();
+
+	final QrCodeDecoder qrCodeDecoder;
+	final BroadcastReceiver bluetoothReceiver = new BluetoothStateReceiver();
+
+	@Nullable
+	private final BluetoothAdapter bt;
+	@Nullable
+	private final Plugin wifiPlugin, bluetoothPlugin;
+
+	// UiThread
+	private BluetoothDecision bluetoothDecision = BluetoothDecision.UNKNOWN;
+
+	private boolean wasContinueClicked = false;
+	private boolean isActivityResumed = false;
+
+	/**
+	 * Records whether we've enabled the wifi plugin so we don't enable it more
+	 * than once.
+	 */
+	private boolean hasEnabledWifi = false;
+
+	/**
+	 * Records whether we've enabled the Bluetooth plugin so we don't enable it
+	 * more than once.
+	 */
+	private boolean hasEnabledBluetooth = false;
+
+	@Nullable
+	private KeyAgreementTask task;
+	private volatile boolean gotLocalPayload = false, gotRemotePayload = false;
+
+	@Inject
+	AddNearbyContactViewModel(Application app,
+			EventBus eventBus,
+			AndroidExecutor androidExecutor,
+			@IoExecutor Executor ioExecutor,
+			PluginManager pluginManager,
+			PayloadEncoder payloadEncoder,
+			PayloadParser payloadParser,
+			Provider<KeyAgreementTask> keyAgreementTaskProvider,
+			ContactExchangeManager contactExchangeManager,
+			ConnectionManager connectionManager) {
+		super(app);
+		this.eventBus = eventBus;
+		this.androidExecutor = androidExecutor;
+		this.ioExecutor = ioExecutor;
+		this.pluginManager = pluginManager;
+		this.payloadEncoder = payloadEncoder;
+		this.payloadParser = payloadParser;
+		this.keyAgreementTaskProvider = keyAgreementTaskProvider;
+		this.contactExchangeManager = contactExchangeManager;
+		this.connectionManager = connectionManager;
+		bt = BluetoothAdapter.getDefaultAdapter();
+		wifiPlugin = pluginManager.getPlugin(LanTcpConstants.ID);
+		bluetoothPlugin = pluginManager.getPlugin(BluetoothConstants.ID);
+		qrCodeDecoder = new QrCodeDecoder(androidExecutor, ioExecutor, this);
+		eventBus.addListener(this);
+		IntentFilter filter = new IntentFilter(ACTION_SCAN_MODE_CHANGED);
+		getApplication().registerReceiver(bluetoothReceiver, filter);
+	}
+
+	@Override
+	protected void onCleared() {
+		super.onCleared();
+		getApplication().unregisterReceiver(bluetoothReceiver);
+		eventBus.removeListener(this);
+		stopListening();
+	}
+
+	@UiThread
+	void onContinueClicked() {
+		if (bluetoothDecision == REFUSED) {
+			bluetoothDecision = UNKNOWN; // Ask again
+		}
+		wasContinueClicked = true;
+		checkPermissions.setEvent(true);
+		showQrCodeFragmentIfAllowed();
+	}
+
+	@UiThread
+	boolean isBluetoothSupported() {
+		return bt != null && bluetoothPlugin != null;
+	}
+
+	@UiThread
+	boolean isWifiReady() {
+		if (wifiPlugin == null) return true; // Continue without wifi
+		State state = wifiPlugin.getState();
+		// Wait for plugin to become enabled
+		return state == ACTIVE || state == INACTIVE;
+	}
+
+	@UiThread
+	boolean isBluetoothReady() {
+		if (bt == null || bluetoothPlugin == null) {
+			// Continue without Bluetooth
+			return true;
+		}
+		if (bluetoothDecision == BluetoothDecision.UNKNOWN ||
+				bluetoothDecision == BluetoothDecision.WAITING ||
+				bluetoothDecision == BluetoothDecision.REFUSED) {
+			// Wait for user to accept
+			return false;
+		}
+		if (bt.getScanMode() != SCAN_MODE_CONNECTABLE_DISCOVERABLE) {
+			// Wait for adapter to become discoverable
+			return false;
+		}
+		// Wait for plugin to become active
+		return bluetoothPlugin.getState() == ACTIVE;
+	}
+
+	@UiThread
+	void enableWifiIfWeShould() {
+		if (hasEnabledWifi) return;
+		if (wifiPlugin == null) return;
+		State state = wifiPlugin.getState();
+		if (state == STARTING_STOPPING || state == DISABLED) {
+			LOG.info("Enabling wifi plugin");
+			hasEnabledWifi = true;
+			pluginManager.setPluginEnabled(LanTcpConstants.ID, true);
+		}
+	}
+
+	@UiThread
+	void enableBluetoothIfWeShould() {
+		if (bluetoothDecision != BluetoothDecision.ACCEPTED) return;
+		if (hasEnabledBluetooth) return;
+		if (bluetoothPlugin == null || !isBluetoothSupported()) return;
+		State state = bluetoothPlugin.getState();
+		if (state == STARTING_STOPPING || state == DISABLED) {
+			LOG.info("Enabling Bluetooth plugin");
+			hasEnabledBluetooth = true;
+			pluginManager.setPluginEnabled(BluetoothConstants.ID, true);
+		}
+	}
+
+	@UiThread
+	void startAddingContact() {
+		// If we return to the intro fragment, the continue button needs to be
+		// clicked again before showing the QR code fragment
+		wasContinueClicked = false;
+		// If we return to the intro fragment, ask for Bluetooth
+		// discoverability again before showing the QR code fragment
+		bluetoothDecision = UNKNOWN;
+		// If we return to the intro fragment, we may need to enable wifi and
+		// Bluetooth again
+		hasEnabledWifi = false;
+		hasEnabledBluetooth = false;
+		// start to listen with a KeyAgreementTask
+		startListening();
+		showQrCodeFragment.setEvent(true);
+	}
+
+	/**
+	 * Call this once Bluetooth and Wi-Fi are ready to be used.
+	 * It is possible to call this more than once over the ViewModel's lifetime.
+	 */
+	@UiThread
+	private void startListening() {
+		KeyAgreementTask oldTask = task;
+		KeyAgreementTask newTask = keyAgreementTaskProvider.get();
+		task = newTask;
+		ioExecutor.execute(() -> {
+			if (oldTask != null) oldTask.stopListening();
+			newTask.listen();
+		});
+	}
+
+	@UiThread
+	private void stopListening() {
+		KeyAgreementTask oldTask = task;
+		ioExecutor.execute(() -> {
+			if (oldTask != null) oldTask.stopListening();
+		});
+	}
+
+	@Override
+	public void eventOccurred(Event e) {
+		if (e instanceof TransportStateEvent) {
+			TransportStateEvent t = (TransportStateEvent) e;
+			if (t.getTransportId().equals(BluetoothConstants.ID)) {
+				if (LOG.isLoggable(INFO)) {
+					LOG.info("Bluetooth state changed to " + t.getState());
+				}
+				showQrCodeFragmentIfAllowed();
+			} else if (t.getTransportId().equals(LanTcpConstants.ID)) {
+				if (LOG.isLoggable(INFO)) {
+					LOG.info("Wifi state changed to " + t.getState());
+				}
+				showQrCodeFragmentIfAllowed();
+			}
+		} else if (e instanceof KeyAgreementListeningEvent) {
+			LOG.info("KeyAgreementListeningEvent received");
+			KeyAgreementListeningEvent event = (KeyAgreementListeningEvent) e;
+			onLocalPayloadReceived(event.getLocalPayload());
+		} else if (e instanceof KeyAgreementWaitingEvent) {
+			LOG.info("KeyAgreementWaitingEvent received");
+			state.setValue(new KeyAgreementWaiting());
+		} else if (e instanceof KeyAgreementStartedEvent) {
+			LOG.info("KeyAgreementStartedEvent received");
+			state.setValue(new KeyAgreementStarted());
+		} else if (e instanceof KeyAgreementFinishedEvent) {
+			LOG.info("KeyAgreementFinishedEvent received");
+			KeyAgreementResult result =
+					((KeyAgreementFinishedEvent) e).getResult();
+			startContactExchange(result);
+			state.setValue(new ContactExchangeStarted());
+		} else if (e instanceof KeyAgreementAbortedEvent) {
+			LOG.info("KeyAgreementAbortedEvent received");
+			resetPayloadFlags();
+			state.setValue(new AddContactState.Failed());
+		} else if (e instanceof KeyAgreementFailedEvent) {
+			LOG.info("KeyAgreementFailedEvent received");
+			resetPayloadFlags();
+			state.setValue(new AddContactState.Failed());
+		}
+	}
+
+	@SuppressWarnings("StatementWithEmptyBody")
+	@UiThread
+	void showQrCodeFragmentIfAllowed() {
+		boolean permissionsGranted = areEssentialPermissionsGranted(
+				getApplication(), isBluetoothSupported());
+		if (isActivityResumed && wasContinueClicked && permissionsGranted) {
+			if (isWifiReady() && isBluetoothReady()) {
+				LOG.info("Wifi and Bluetooth are ready");
+				startAddingContact();
+			} else {
+				enableWifiIfWeShould();
+				if (bluetoothDecision == UNKNOWN) {
+					requestBluetoothDiscoverable.setEvent(true);
+				} else if (bluetoothDecision == REFUSED) {
+					// Ask again when the user clicks "continue"
+				} else {
+					enableBluetoothIfWeShould();
+				}
+			}
+		}
+	}
+
+	/**
+	 * This sets the QR code by setting the state to KeyAgreementListening.
+	 */
+	private void onLocalPayloadReceived(Payload localPayload) {
+		if (gotLocalPayload) return;
+		DisplayMetrics dm = getApplication().getResources().getDisplayMetrics();
+		ioExecutor.execute(() -> {
+			byte[] payloadBytes = payloadEncoder.encode(localPayload);
+			if (LOG.isLoggable(INFO)) {
+				LOG.info("Local payload is " + payloadBytes.length
+						+ " bytes");
+			}
+			// Use ISO 8859-1 to encode bytes directly as a string
+			String content = new String(payloadBytes, ISO_8859_1);
+			Bitmap qrCode = QrCodeUtils.createQrCode(dm, content);
+			gotLocalPayload = true;
+			state.postValue(new KeyAgreementListening(qrCode));
+		});
+	}
+
+	@Override
+	@IoExecutor
+	public void onQrCodeDecoded(Result result) {
+		LOG.info("Got result from decoder");
+		// Ignore results until the KeyAgreementTask is ready
+		if (!gotLocalPayload || gotRemotePayload) return;
+		try {
+			byte[] payloadBytes = result.getText().getBytes(ISO_8859_1);
+			if (LOG.isLoggable(INFO))
+				LOG.info("Remote payload is " + payloadBytes.length + " bytes");
+			Payload remotePayload = payloadParser.parse(payloadBytes);
+			gotRemotePayload = true;
+			requireNonNull(task).connectAndRunProtocol(remotePayload);
+			state.postValue(new AddContactState.QrCodeScanned());
+		} catch (UnsupportedVersionException e) {
+			resetPayloadFlags();
+			state.postValue(new AddContactState.Failed(e.isTooOld()));
+		} catch (IOException | IllegalArgumentException e) {
+			LOG.log(WARNING, "QR Code Invalid", e);
+			androidExecutor.runOnUiThread(() -> Toast.makeText(getApplication(),
+					R.string.qr_code_invalid, LENGTH_LONG).show());
+			resetPayloadFlags();
+			state.postValue(new AddContactState.Failed());
+		}
+	}
+
+	private void resetPayloadFlags() {
+		gotRemotePayload = false;
+		gotLocalPayload = false;
+	}
+
+	@UiThread
+	private void startContactExchange(KeyAgreementResult result) {
+		TransportId t = result.getTransportId();
+		DuplexTransportConnection conn = result.getConnection();
+		SecretKey masterKey = result.getMasterKey();
+		boolean alice = result.wasAlice();
+		ioExecutor.execute(() -> {
+			try {
+				Contact contact = contactExchangeManager.exchangeContacts(conn,
+						masterKey, alice, true);
+				// Reuse the connection as a transport connection
+				connectionManager
+						.manageOutgoingConnection(contact.getId(), t, conn);
+				Success success = new Success(contact.getAuthor());
+				state.postValue(new ContactExchangeFinished(success));
+			} catch (ContactExistsException e) {
+				tryToClose(conn);
+				Error error = new Error(e.getRemoteAuthor());
+				state.postValue(new ContactExchangeFinished(error));
+			} catch (DbException | IOException e) {
+				tryToClose(conn);
+				logException(LOG, WARNING, e);
+				Error error = new Error(null);
+				state.postValue(new ContactExchangeFinished(error));
+			}
+		});
+	}
+
+	private class BluetoothStateReceiver extends BroadcastReceiver {
+		@UiThread
+		@Override
+		public void onReceive(Context context, Intent intent) {
+			int scanMode = intent.getIntExtra(EXTRA_SCAN_MODE, -1);
+			LOG.info("Bluetooth scan mode changed: " + scanMode);
+			showQrCodeFragmentIfAllowed();
+		}
+	}
+
+	private void tryToClose(DuplexTransportConnection conn) {
+		try {
+			conn.getReader().dispose(true, true);
+			conn.getWriter().dispose(true);
+		} catch (IOException e) {
+			logException(LOG, WARNING, e);
+		}
+	}
+
+	/**
+	 * Set to true in onPostResume() and false in onPause(). This prevents the
+	 * QR code fragment from being shown if onRequestPermissionsResult() is
+	 * called while the activity is paused, which could cause a crash due to
+	 * https://issuetracker.google.com/issues/37067655.
+	 * TODO check if this is still happening with new permission requesting
+	 */
+	@UiThread
+	void setIsActivityResumed(boolean resumed) {
+		isActivityResumed = resumed;
+		// Workaround for
+		// https://code.google.com/p/android/issues/detail?id=190966
+		showQrCodeFragmentIfAllowed();
+	}
+
+	@UiThread
+	void setBluetoothDecision(BluetoothDecision decision) {
+		bluetoothDecision = decision;
+		showQrCodeFragmentIfAllowed();
+	}
+
+	LiveEvent<Boolean> getCheckPermissions() {
+		return checkPermissions;
+	}
+
+	LiveEvent<Boolean> getRequestBluetoothDiscoverable() {
+		return requestBluetoothDiscoverable;
+	}
+
+	LiveEvent<Boolean> getShowQrCodeFragment() {
+		return showQrCodeFragment;
+	}
+
+	LiveData<AddContactState> getState() {
+		return state;
+	}
+
+}

briar-android/src/main/java/org/briarproject/briar/android/contact/add/nearby/CameraException.java

@@ -1,4 +1,4 @@
-package org.briarproject.briar.android.keyagreement;
+package org.briarproject.briar.android.contact.add.nearby;
 
 import java.io.IOException;
 

briar-android/src/main/java/org/briarproject/briar/android/contact/add/nearby/CameraView.java

@@ -1,4 +1,4 @@
-package org.briarproject.briar.android.keyagreement;
+package org.briarproject.briar.android.contact.add.nearby;
 
 import android.content.Context;
 import android.hardware.Camera;
@@ -40,7 +40,6 @@ import static java.util.logging.Level.INFO;
 import static java.util.logging.Level.WARNING;
 import static org.briarproject.bramble.util.LogUtils.logException;
 
-@SuppressWarnings("deprecation")
 @MethodsNotNullByDefault
 @ParametersNotNullByDefault
 public class CameraView extends SurfaceView implements SurfaceHolder.Callback,
@@ -126,8 +125,14 @@ public class CameraView extends SurfaceView implements SurfaceHolder.Callback,
 			throw new CameraException(e);
 		}
 		setDisplayOrientation(getScreenRotationDegrees());
+		if (camera == null) throw new CameraException("No camera found");
 		// Use barcode scene mode if it's available
-		Parameters params = camera.getParameters();
+		Parameters params;
+		try {
+			params = camera.getParameters();
+		} catch (RuntimeException e) {
+			throw new CameraException(e);
+		}
 		params = setSceneMode(camera, params);
 		if (SCENE_MODE_BARCODE.equals(params.getSceneMode())) {
 			// If the scene mode enabled the flash, try to disable it

briar-android/src/main/java/org/briarproject/briar/android/contact/add/nearby/PreviewConsumer.java

@@ -1,4 +1,4 @@
-package org.briarproject.briar.android.keyagreement;
+package org.briarproject.briar.android.contact.add.nearby;
 
 import android.hardware.Camera;
 
@@ -6,7 +6,6 @@ import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
 
 import androidx.annotation.UiThread;
 
-@SuppressWarnings("deprecation")
 @NotNullByDefault
 interface PreviewConsumer {
 

briar-android/src/main/java/org/briarproject/briar/android/contact/add/nearby/QrCodeDecoder.java

@@ -1,10 +1,9 @@
-package org.briarproject.briar.android.keyagreement;
+package org.briarproject.briar.android.contact.add.nearby;
 
 import android.hardware.Camera;
 import android.hardware.Camera.CameraInfo;
 import android.hardware.Camera.PreviewCallback;
 import android.hardware.Camera.Size;
-import android.os.AsyncTask;
 
 import com.google.zxing.BinaryBitmap;
 import com.google.zxing.LuminanceSource;
@@ -15,10 +14,13 @@ import com.google.zxing.Result;
 import com.google.zxing.common.HybridBinarizer;
 import com.google.zxing.qrcode.QRCodeReader;
 
+import org.briarproject.bramble.api.lifecycle.IoExecutor;
 import org.briarproject.bramble.api.nullsafety.MethodsNotNullByDefault;
 import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
 import org.briarproject.bramble.api.nullsafety.ParametersNotNullByDefault;
+import org.briarproject.bramble.api.system.AndroidExecutor;
 
+import java.util.concurrent.Executor;
 import java.util.logging.Logger;
 
 import androidx.annotation.UiThread;
@@ -26,22 +28,26 @@ import androidx.annotation.UiThread;
 import static com.google.zxing.DecodeHintType.CHARACTER_SET;
 import static java.util.Collections.singletonMap;
 import static java.util.logging.Level.WARNING;
+import static java.util.logging.Logger.getLogger;
 
-@SuppressWarnings("deprecation")
 @MethodsNotNullByDefault
 @ParametersNotNullByDefault
 class QrCodeDecoder implements PreviewConsumer, PreviewCallback {
 
-	private static final Logger LOG =
+	private static final Logger LOG = getLogger(QrCodeDecoder.class.getName());
-			Logger.getLogger(QrCodeDecoder.class.getName());
 
+	private final AndroidExecutor androidExecutor;
+	private final Executor ioExecutor;
 	private final Reader reader = new QRCodeReader();
 	private final ResultCallback callback;
 
 	private Camera camera = null;
 	private int cameraIndex = 0;
 
-	QrCodeDecoder(ResultCallback callback) {
+	QrCodeDecoder(AndroidExecutor androidExecutor,
+			@IoExecutor Executor ioExecutor, ResultCallback callback) {
+		this.androidExecutor = androidExecutor;
+		this.ioExecutor = ioExecutor;
 		this.callback = callback;
 	}
 
@@ -74,8 +80,7 @@ class QrCodeDecoder implements PreviewConsumer, PreviewCallback {
 				if (data.length == size.width * size.height * 3 / 2) {
 					CameraInfo info = new CameraInfo();
 					Camera.getCameraInfo(cameraIndex, info);
-					new DecoderTask(data, size.width, size.height,
+					decode(data, size.width, size.height, info.orientation);
-							info.orientation).execute();
 				} else {
 					// Camera parameters have changed - ask for a new preview
 					LOG.info("Preview size does not match camera parameters");
@@ -89,43 +94,23 @@ class QrCodeDecoder implements PreviewConsumer, PreviewCallback {
 		}
 	}
 
-	private class DecoderTask extends AsyncTask<Void, Void, Void> {
+	private void decode(byte[] data, int width, int height, int orientation) {
-
+		ioExecutor.execute(() -> {
-		private final byte[] data;
-		private final int width, height, orientation;
-
-		private DecoderTask(byte[] data, int width, int height,
-				int orientation) {
-			this.data = data;
-			this.width = width;
-			this.height = height;
-			this.orientation = orientation;
-		}
-
-		@Override
-		protected Void doInBackground(Void... params) {
 			BinaryBitmap bitmap = binarize(data, width, height, orientation);
 			Result result;
 			try {
 				result = reader.decode(bitmap,
 						singletonMap(CHARACTER_SET, "ISO8859_1"));
+				callback.onQrCodeDecoded(result);
 			} catch (ReaderException e) {
 				// No barcode found
-				return null;
 			} catch (RuntimeException e) {
 				LOG.warning("Invalid preview frame");
-				return null;
 			} finally {
 				reader.reset();
+				androidExecutor.runOnUiThread(this::askForPreviewFrame);
 			}
-			callback.handleResult(result);
+		});
-			return null;
-		}
-
-		@Override
-		protected void onPostExecute(Void result) {
-			askForPreviewFrame();
-		}
 	}
 
 	private static BinaryBitmap binarize(byte[] data, int width, int height,
@@ -143,7 +128,7 @@ class QrCodeDecoder implements PreviewConsumer, PreviewCallback {
 
 	@NotNullByDefault
 	interface ResultCallback {
-
+		@IoExecutor
-		void handleResult(Result result);
+		void onQrCodeDecoded(Result result);
 	}
 }

briar-android/src/main/java/org/briarproject/briar/android/contact/add/nearby/QrCodeUtils.java

@@ -1,4 +1,4 @@
-package org.briarproject.briar.android.keyagreement;
+package org.briarproject.briar.android.contact.add.nearby;
 
 import android.graphics.Bitmap;
 import android.util.DisplayMetrics;
@@ -18,13 +18,13 @@ import static android.graphics.Color.BLACK;
 import static android.graphics.Color.WHITE;
 import static com.google.zxing.BarcodeFormat.QR_CODE;
 import static java.util.logging.Level.WARNING;
+import static java.util.logging.Logger.getLogger;
 import static org.briarproject.bramble.util.LogUtils.logException;
 
 @NotNullByDefault
 class QrCodeUtils {
 
-	private static final Logger LOG =
+	private static final Logger LOG = getLogger(QrCodeUtils.class.getName());
-			Logger.getLogger(QrCodeUtils.class.getName());
 
 	@Nullable
 	static Bitmap createQrCode(DisplayMetrics dm, String input) {

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

@@ -6,6 +6,7 @@ import org.briarproject.bramble.api.contact.ContactId;
 import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
 import org.briarproject.briar.android.contact.BaseContactListAdapter;
 import org.briarproject.briar.android.contact.ContactItemViewHolder;
+import org.briarproject.briar.android.contact.OnContactClickListener;
 
 import java.util.ArrayList;
 import java.util.Collection;

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

@@ -12,8 +12,8 @@ import org.briarproject.bramble.api.nullsafety.MethodsNotNullByDefault;
 import org.briarproject.bramble.api.nullsafety.ParametersNotNullByDefault;
 import org.briarproject.bramble.api.sync.GroupId;
 import org.briarproject.briar.R;
-import org.briarproject.briar.android.contact.BaseContactListAdapter.OnContactClickListener;
 import org.briarproject.briar.android.contact.ContactItemViewHolder;
+import org.briarproject.briar.android.contact.OnContactClickListener;
 import org.briarproject.briar.android.controller.handler.UiResultExceptionHandler;
 import org.briarproject.briar.android.fragment.BaseFragment;
 import org.briarproject.briar.android.view.BriarRecyclerView;

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

@@ -6,8 +6,8 @@ import android.widget.TextView;
 
 import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
 import org.briarproject.briar.R;
-import org.briarproject.briar.android.contact.BaseContactListAdapter.OnContactClickListener;
 import org.briarproject.briar.android.contact.ContactItemViewHolder;
+import org.briarproject.briar.android.contact.OnContactClickListener;
 
 import javax.annotation.Nullable;
 

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

@@ -7,6 +7,7 @@ import android.view.ViewGroup;
 
 import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
 import org.briarproject.briar.R;
+import org.briarproject.briar.android.contact.OnContactClickListener;
 
 @NotNullByDefault
 class ContactSelectorAdapter extends

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

@@ -8,7 +8,7 @@ import android.view.MenuItem;
 import org.briarproject.bramble.api.nullsafety.MethodsNotNullByDefault;
 import org.briarproject.bramble.api.nullsafety.ParametersNotNullByDefault;
 import org.briarproject.briar.R;
-import org.briarproject.briar.android.contact.BaseContactListAdapter.OnContactClickListener;
+import org.briarproject.briar.android.contact.OnContactClickListener;
 
 @MethodsNotNullByDefault
 @ParametersNotNullByDefault

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

@@ -3,7 +3,7 @@ package org.briarproject.briar.android.contactselection;
 import android.view.View;
 
 import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
-import org.briarproject.briar.android.contact.BaseContactListAdapter.OnContactClickListener;
+import org.briarproject.briar.android.contact.OnContactClickListener;
 
 import javax.annotation.Nullable;
 

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

@@ -24,10 +24,7 @@ import org.briarproject.briar.android.attachment.AttachmentItem;
 import org.briarproject.briar.android.util.BriarSnackbarBuilder;
 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;
 
@@ -293,13 +290,10 @@ public class ImageActivity extends BriarActivity
 
 	@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);
+		intent.putExtra(EXTRA_TITLE, viewModel.getFileName());
 		return intent;
 	}
 

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

@@ -225,8 +225,8 @@ public class ImageViewModel extends DbViewModel implements EventListener {
 		});
 	}
 
-	private String getFileName() {
+	String getFileName() {
-		SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd'T'HH:mm:ss",
+		SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd",
 				Locale.getDefault());
 		return sdf.format(new Date());
 	}

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

@@ -10,9 +10,8 @@ import org.briarproject.bramble.api.nullsafety.ParametersNotNullByDefault;
 import org.briarproject.briar.android.DestroyableContext;
 import org.briarproject.briar.android.activity.ActivityComponent;
 
-import javax.annotation.Nullable;
-
 import androidx.annotation.CallSuper;
+import androidx.annotation.Nullable;
 import androidx.annotation.UiThread;
 import androidx.fragment.app.Fragment;
 import androidx.fragment.app.FragmentActivity;
@@ -47,13 +46,11 @@ public abstract class BaseFragment extends Fragment
 
 	@Override
 	public boolean onOptionsItemSelected(MenuItem item) {
-		switch (item.getItemId()) {
+		if (item.getItemId() == android.R.id.home) {
-			case android.R.id.home:
+			requireActivity().onBackPressed();
-				listener.onBackPressed();
+			return true;
-				return true;
-			default:
-				return super.onOptionsItemSelected(item);
 		}
+		return super.onOptionsItemSelected(item);
 	}
 
 	@UiThread
@@ -79,6 +76,7 @@ public abstract class BaseFragment extends Fragment
 		void handleException(Exception e);
 	}
 
+	@Deprecated
 	@CallSuper
 	@Override
 	public void runOnUiThreadUnlessDestroyed(Runnable r) {

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

@@ -5,74 +5,41 @@ import android.view.LayoutInflater;
 import android.view.View;
 import android.view.ViewGroup;
 
-import org.briarproject.bramble.api.connection.ConnectionRegistry;
-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.briar.R;
 import org.briarproject.briar.android.activity.ActivityComponent;
-import org.briarproject.briar.android.contact.BaseContactListAdapter.OnContactClickListener;
+import org.briarproject.briar.android.contact.ContactListAdapter;
 import org.briarproject.briar.android.contact.ContactListItem;
-import org.briarproject.briar.android.contact.LegacyContactListAdapter;
+import org.briarproject.briar.android.contact.OnContactClickListener;
 import org.briarproject.briar.android.fragment.BaseFragment;
 import org.briarproject.briar.android.view.BriarRecyclerView;
-import org.briarproject.briar.api.client.MessageTracker.GroupCount;
-import org.briarproject.briar.api.conversation.ConversationManager;
-import org.briarproject.briar.api.identity.AuthorInfo;
-import org.briarproject.briar.api.identity.AuthorManager;
-
-import java.util.ArrayList;
-import java.util.List;
-import java.util.logging.Logger;
 
 import javax.inject.Inject;
 
 import androidx.annotation.Nullable;
-import androidx.annotation.UiThread;
+import androidx.lifecycle.ViewModelProvider;
 import androidx.recyclerview.widget.LinearLayoutManager;
 
-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 class ContactChooserFragment extends BaseFragment
+		implements OnContactClickListener<ContactListItem> {
 
-	public static final String TAG = ContactChooserFragment.class.getName();
+	private static final String TAG = ContactChooserFragment.class.getName();
-	private static final Logger LOG = Logger.getLogger(TAG);
 
+	@Inject
+	ViewModelProvider.Factory viewModelFactory;
+
+	private IntroductionViewModel viewModel;
+	private final ContactListAdapter adapter = new ContactListAdapter(this);
 	private BriarRecyclerView list;
-	private LegacyContactListAdapter adapter;
-	private ContactId contactId;
-
-	// Fields that are accessed from background threads must be volatile
-	private volatile Contact c1;
-	@Inject
-	volatile ContactManager contactManager;
-	@Inject
-	volatile AuthorManager authorManager;
-	@Inject
-	volatile ConversationManager conversationManager;
-	@Inject
-	volatile ConnectionRegistry connectionRegistry;
-
-	public static ContactChooserFragment newInstance(ContactId id) {
-		Bundle args = new Bundle();
-
-		ContactChooserFragment fragment = new ContactChooserFragment();
-		args.putInt(CONTACT_ID, id.getInt());
-		fragment.setArguments(args);
-		return fragment;
-	}
 
 	@Override
 	public void injectFragment(ActivityComponent component) {
 		component.inject(this);
+		viewModel = new ViewModelProvider(requireActivity(), viewModelFactory)
+				.get(IntroductionViewModel.class);
 	}
 
 	@Override
@@ -80,23 +47,20 @@ public class ContactChooserFragment extends BaseFragment {
 			@Nullable ViewGroup container,
 			@Nullable Bundle savedInstanceState) {
 
-		View contentView = inflater.inflate(R.layout.list, container, false);
+		// change toolbar text (relevant when navigating back to this fragment)
+		requireActivity().setTitle(R.string.introduction_activity_title);
 
-		OnContactClickListener<ContactListItem> onContactClickListener =
+		View contentView = inflater.inflate(R.layout.list, container, false);
-				(view, item) -> {
-					if (c1 == null) throw new IllegalStateException();
-					Contact c2 = item.getContact();
-					showMessageScreen(c1, c2);
-				};
-		adapter = new LegacyContactListAdapter(requireActivity(),
-				onContactClickListener);
 
 		list = contentView.findViewById(R.id.list);
 		list.setLayoutManager(new LinearLayoutManager(getActivity()));
 		list.setAdapter(adapter);
 		list.setEmptyText(R.string.no_contacts);
 
-		contactId = new ContactId(requireArguments().getInt(CONTACT_ID));
+		viewModel.getContactListItems().observe(getViewLifecycleOwner(),
+				result -> result.onError(this::handleException)
+						.onSuccess(adapter::submitList)
+		);
 
 		return contentView;
 	}
@@ -104,14 +68,13 @@ public class ContactChooserFragment extends BaseFragment {
 	@Override
 	public void onStart() {
 		super.onStart();
-		loadContacts();
+		list.startPeriodicUpdate();
 	}
 
 	@Override
 	public void onStop() {
 		super.onStop();
-		adapter.clear();
+		list.stopPeriodicUpdate();
-		list.showProgressBar();
 	}
 
 	@Override
@@ -119,43 +82,9 @@ public class ContactChooserFragment extends BaseFragment {
 		return TAG;
 	}
 
-	private void loadContacts() {
+	@Override
-		listener.runOnDbThread(() -> {
+	public void onItemClick(View view, ContactListItem item) {
-			try {
+		viewModel.setSecondContactId(item.getContact().getId());
-				List<ContactListItem> contacts = new ArrayList<>();
+		viewModel.triggerContactSelected();
-				for (Contact c : contactManager.getContacts()) {
-					if (c.getId().equals(contactId)) {
-						c1 = c;
-					} else {
-						AuthorInfo authorInfo = authorManager.getAuthorInfo(c);
-						ContactId id = c.getId();
-						GroupCount count =
-								conversationManager.getGroupCount(id);
-						boolean connected =
-								connectionRegistry.isConnected(c.getId());
-						contacts.add(new ContactListItem(c, authorInfo,
-								connected, count));
-					}
-				}
-				displayContacts(contacts);
-			} catch (DbException e) {
-				logException(LOG, WARNING, e);
-			}
-		});
 	}
-
-	private void displayContacts(List<ContactListItem> contacts) {
-		runOnUiThreadUnlessDestroyed(() -> {
-			if (contacts.isEmpty()) list.showData();
-			else adapter.addAll(contacts);
-		});
-	}
-
-	private void showMessageScreen(Contact c1, Contact c2) {
-		IntroductionMessageFragment messageFragment =
-				IntroductionMessageFragment
-						.newInstance(c1.getId().getInt(), c2.getId().getInt());
-		showNextFragment(messageFragment);
-	}
-
 }

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

@@ -9,30 +9,67 @@ import org.briarproject.briar.android.activity.ActivityComponent;
 import org.briarproject.briar.android.activity.BriarActivity;
 import org.briarproject.briar.android.fragment.BaseFragment.BaseFragmentListener;
 
+import javax.inject.Inject;
+
+import androidx.annotation.NonNull;
+import androidx.lifecycle.ViewModelProvider;
+
 import static org.briarproject.briar.android.conversation.ConversationActivity.CONTACT_ID;
 
 public class IntroductionActivity extends BriarActivity
 		implements BaseFragmentListener {
 
+	@Inject
+	ViewModelProvider.Factory viewModelFactory;
+
+	private IntroductionViewModel viewModel;
+
+	@Override
+	public void injectActivity(ActivityComponent component) {
+		component.inject(this);
+		viewModel = new ViewModelProvider(this, viewModelFactory)
+				.get(IntroductionViewModel.class);
+	}
+
+	private static final String BUNDLE_CONTACT2 = "contact2";
+
 	@Override
 	public void onCreate(Bundle savedInstanceState) {
 		super.onCreate(savedInstanceState);
 
 		Intent intent = getIntent();
-		int id = intent.getIntExtra(CONTACT_ID, -1);
+		int contactId1 = intent.getIntExtra(CONTACT_ID, -1);
-		if (id == -1) throw new IllegalStateException("No ContactId");
+		if (contactId1 == -1)
-		ContactId contactId = new ContactId(id);
+			throw new IllegalStateException("No ContactId");
+		ContactId firstContactId = new ContactId(contactId1);
+
+		viewModel.setFirstContactId(firstContactId);
 
 		setContentView(R.layout.activity_fragment_container);
 
 		if (savedInstanceState == null) {
-			showInitialFragment(ContactChooserFragment.newInstance(contactId));
+			showInitialFragment(new ContactChooserFragment());
+		} else {
+			int contactId2 = savedInstanceState.getInt(BUNDLE_CONTACT2);
+			ContactId secondContactId = new ContactId(contactId2);
+			viewModel.setSecondContactId(secondContactId);
 		}
+
+		viewModel.getSecondContactSelected().observeEvent(this, e -> {
+			IntroductionMessageFragment fragment =
+					new IntroductionMessageFragment();
+			showNextFragment(fragment);
+		});
 	}
 
 	@Override
-	public void injectActivity(ActivityComponent component) {
+	public void onSaveInstanceState(@NonNull Bundle outState) {
-		component.inject(this);
+		super.onSaveInstanceState(outState);
+
+		ContactId secondContactId = viewModel.getSecondContactId();
+		if (secondContactId != null) {
+			outState.putInt(BUNDLE_CONTACT2, secondContactId.getInt());
+		}
 	}
 
 }

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

@@ -0,0 +1,28 @@
+package org.briarproject.briar.android.introduction;
+
+import org.briarproject.briar.android.contact.ContactItem;
+
+class IntroductionInfo {
+	private final ContactItem c1;
+	private final ContactItem c2;
+	private final boolean possible;
+
+	IntroductionInfo(ContactItem c1, ContactItem c2,
+			boolean possible) {
+		this.c1 = c1;
+		this.c2 = c2;
+		this.possible = possible;
+	}
+
+	ContactItem getContact1() {
+		return c1;
+	}
+
+	ContactItem getContact2() {
+		return c2;
+	}
+
+	boolean isPossible() {
+		return possible;
+	}
+}

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

@@ -1,6 +1,5 @@
 package org.briarproject.briar.android.introduction;
 
-import android.content.Context;
 import android.os.Bundle;
 import android.view.LayoutInflater;
 import android.view.MenuItem;
@@ -8,12 +7,7 @@ import android.view.View;
 import android.view.ViewGroup;
 import android.widget.ProgressBar;
 import android.widget.TextView;
-import android.widget.Toast;
 
-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.briar.R;
@@ -24,25 +18,19 @@ import org.briarproject.briar.android.view.TextInputView;
 import org.briarproject.briar.android.view.TextSendController;
 import org.briarproject.briar.android.view.TextSendController.SendListener;
 import org.briarproject.briar.api.attachment.AttachmentHeader;
-import org.briarproject.briar.api.identity.AuthorInfo;
-import org.briarproject.briar.api.identity.AuthorManager;
-import org.briarproject.briar.api.introduction.IntroductionManager;
 
 import java.util.List;
-import java.util.logging.Logger;
 
 import javax.inject.Inject;
 
 import androidx.annotation.Nullable;
-import androidx.appcompat.app.ActionBar;
+import androidx.fragment.app.FragmentActivity;
+import androidx.lifecycle.ViewModelProvider;
 import de.hdodenhof.circleimageview.CircleImageView;
 
 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.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.android.util.UiUtils.hideSoftKeyboard;
 import static org.briarproject.briar.android.view.AuthorView.setAvatar;
@@ -53,45 +41,21 @@ import static org.briarproject.briar.api.introduction.IntroductionConstants.MAX_
 public class IntroductionMessageFragment extends BaseFragment
 		implements SendListener {
 
-	public static final String TAG =
+	private static final String TAG =
 			IntroductionMessageFragment.class.getName();
-	private static final Logger LOG = Logger.getLogger(TAG);
 
-	private final static String CONTACT_ID_1 = "contact1";
+	@Inject
-	private final static String CONTACT_ID_2 = "contact2";
+	ViewModelProvider.Factory viewModelFactory;
+
+	private IntroductionViewModel viewModel;
 
-	private IntroductionActivity introductionActivity;
 	private ViewHolder ui;
-	private Contact contact1, contact2;
-
-	// Fields that are accessed from background threads must be volatile
-	@Inject
-	protected volatile ContactManager contactManager;
-	@Inject
-	protected volatile AuthorManager authorManager;
-	@Inject
-	protected volatile IntroductionManager introductionManager;
-
-	public static IntroductionMessageFragment newInstance(int contactId1,
-			int contactId2) {
-		Bundle args = new Bundle();
-		args.putInt(CONTACT_ID_1, contactId1);
-		args.putInt(CONTACT_ID_2, contactId2);
-		IntroductionMessageFragment fragment =
-				new IntroductionMessageFragment();
-		fragment.setArguments(args);
-		return fragment;
-	}
-
-	@Override
-	public void onAttach(Context context) {
-		super.onAttach(context);
-		introductionActivity = (IntroductionActivity) context;
-	}
 
 	@Override
 	public void injectFragment(ActivityComponent component) {
 		component.inject(this);
+		viewModel = new ViewModelProvider(requireActivity(), viewModelFactory)
+				.get(IntroductionViewModel.class);
 	}
 
 	@Override
@@ -100,18 +64,7 @@ public class IntroductionMessageFragment extends BaseFragment
 			@Nullable Bundle savedInstanceState) {
 
 		// change toolbar text
-		ActionBar actionBar = introductionActivity.getSupportActionBar();
+		requireActivity().setTitle(R.string.introduction_message_title);
-		if (actionBar != null) {
-			actionBar.setTitle(R.string.introduction_message_title);
-		}
-
-		// get contact IDs from fragment arguments
-		Bundle args = requireArguments();
-		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,
@@ -123,69 +76,44 @@ public class IntroductionMessageFragment extends BaseFragment
 		ui.message.setMaxTextLength(MAX_INTRODUCTION_TEXT_LENGTH);
 		ui.message.setReady(false);
 
-		// get contacts and then show view
+		viewModel.getIntroductionInfo().observe(getViewLifecycleOwner(), ii -> {
-		prepareToSetUpViews(contactId1, contactId2);
+			if (ii == null) {
+				return;
+			}
+			setUpViews(ii.getContact1(), ii.getContact2(),
+					ii.isPossible());
+		});
 
 		return v;
 	}
 
-	@Override
-	public void onStart() {
-		super.onStart();
-	}
-
 	@Override
 	public String getUniqueTag() {
 		return TAG;
 	}
 
-	private void prepareToSetUpViews(int contactId1, int contactId2) {
-		introductionActivity.runOnDbThread(() -> {
-			try {
-				Contact contact1 =
-						contactManager.getContact(new ContactId(contactId1));
-				Contact contact2 =
-						contactManager.getContact(new ContactId(contactId2));
-				AuthorInfo a1 = authorManager.getAuthorInfo(contact1);
-				AuthorInfo a2 = authorManager.getAuthorInfo(contact2);
-				boolean possible =
-						introductionManager.canIntroduce(contact1, contact2);
-				ContactItem c1 = new ContactItem(contact1, a1);
-				ContactItem c2 = new ContactItem(contact2, a2);
-				setUpViews(c1, c2, possible);
-			} catch (DbException e) {
-				logException(LOG, WARNING, e);
-			}
-		});
-	}
-
 	private void setUpViews(ContactItem c1, ContactItem c2, boolean possible) {
-		introductionActivity.runOnUiThreadUnlessDestroyed(() -> {
+		// set avatars
-			contact1 = c1.getContact();
+		setAvatar(ui.avatar1, c1);
-			contact2 = c2.getContact();
+		setAvatar(ui.avatar2, c2);
 
-			// set avatars
+		// set contact names
-			setAvatar(ui.avatar1, c1);
+		ui.contactName1.setText(getContactDisplayName(c1.getContact()));
-			setAvatar(ui.avatar2, c2);
+		ui.contactName2.setText(getContactDisplayName(c2.getContact()));
 
-			// set contact names
+		// hide progress bar
-			ui.contactName1.setText(getContactDisplayName(c1.getContact()));
+		ui.progressBar.setVisibility(GONE);
-			ui.contactName2.setText(getContactDisplayName(c2.getContact()));
 
-			// hide progress bar
+		if (possible) {
-			ui.progressBar.setVisibility(GONE);
+			// show views
-
+			ui.notPossible.setVisibility(GONE);
-			if (possible) {
+			ui.message.setVisibility(VISIBLE);
-				// show views
+			ui.message.setReady(true);
-				ui.notPossible.setVisibility(GONE);
+			ui.message.showSoftKeyboard();
-				ui.message.setVisibility(VISIBLE);
+		} else {
-				ui.message.setReady(true);
+			ui.notPossible.setVisibility(VISIBLE);
-				ui.message.showSoftKeyboard();
+			ui.message.setVisibility(GONE);
-			} else {
+		}
-				ui.notPossible.setVisibility(VISIBLE);
-				ui.message.setVisibility(GONE);
-			}
-		});
 	}
 
 	@Override
@@ -193,7 +121,7 @@ public class IntroductionMessageFragment extends BaseFragment
 		switch (item.getItemId()) {
 			case android.R.id.home:
 				hideSoftKeyboard(ui.message);
-				introductionActivity.onBackPressed();
+				requireActivity().onBackPressed();
 				return true;
 			default:
 				return super.onOptionsItemSelected(item);
@@ -206,32 +134,13 @@ public class IntroductionMessageFragment extends BaseFragment
 		// disable button to prevent accidental double invitations
 		ui.message.setReady(false);
 
-		makeIntroduction(contact1, contact2, text);
+		viewModel.makeIntroduction(text);
 
 		// don't wait for the introduction to be made before finishing activity
 		hideSoftKeyboard(ui.message);
-		introductionActivity.setResult(RESULT_OK);
+		FragmentActivity activity = requireActivity();
-		introductionActivity.supportFinishAfterTransition();
+		activity.setResult(RESULT_OK);
-	}
+		activity.supportFinishAfterTransition();
-
-	private void makeIntroduction(Contact c1, Contact c2,
-			@Nullable String text) {
-		introductionActivity.runOnDbThread(() -> {
-			// actually make the introduction
-			try {
-				long timestamp = System.currentTimeMillis();
-				introductionManager.makeIntroduction(c1, c2, text, timestamp);
-			} catch (DbException e) {
-				logException(LOG, WARNING, e);
-				introductionError();
-			}
-		});
-	}
-
-	private void introductionError() {
-		introductionActivity.runOnUiThreadUnlessDestroyed(
-				() -> Toast.makeText(introductionActivity,
-						R.string.introduction_error, LENGTH_SHORT).show());
 	}
 
 	private static class ViewHolder {

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

@@ -0,0 +1,19 @@
+package org.briarproject.briar.android.introduction;
+
+import org.briarproject.briar.android.viewmodel.ViewModelKey;
+
+import androidx.lifecycle.ViewModel;
+import dagger.Binds;
+import dagger.Module;
+import dagger.multibindings.IntoMap;
+
+@Module
+public abstract class IntroductionModule {
+
+	@Binds
+	@IntoMap
+	@ViewModelKey(IntroductionViewModel.class)
+	abstract ViewModel bindIntroductionViewModel(
+			IntroductionViewModel introductionViewModel);
+
+}

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

@@ -0,0 +1,181 @@
+package org.briarproject.briar.android.introduction;
+
+import android.app.Application;
+import android.widget.Toast;
+
+import org.briarproject.bramble.api.connection.ConnectionRegistry;
+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.DatabaseExecutor;
+import org.briarproject.bramble.api.db.DbException;
+import org.briarproject.bramble.api.db.TransactionManager;
+import org.briarproject.bramble.api.event.EventBus;
+import org.briarproject.bramble.api.lifecycle.LifecycleManager;
+import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
+import org.briarproject.bramble.api.system.AndroidExecutor;
+import org.briarproject.briar.R;
+import org.briarproject.briar.android.contact.ContactItem;
+import org.briarproject.briar.android.contact.ContactsViewModel;
+import org.briarproject.briar.android.viewmodel.LiveEvent;
+import org.briarproject.briar.android.viewmodel.MutableLiveEvent;
+import org.briarproject.briar.api.conversation.ConversationManager;
+import org.briarproject.briar.api.identity.AuthorInfo;
+import org.briarproject.briar.api.identity.AuthorManager;
+import org.briarproject.briar.api.introduction.IntroductionManager;
+
+import java.util.concurrent.Executor;
+import java.util.logging.Logger;
+
+import javax.inject.Inject;
+
+import androidx.annotation.Nullable;
+import androidx.lifecycle.LiveData;
+import androidx.lifecycle.MutableLiveData;
+
+import static android.widget.Toast.LENGTH_SHORT;
+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.LogUtils.logException;
+
+@NotNullByDefault
+class IntroductionViewModel extends ContactsViewModel {
+
+	private static final Logger LOG =
+			getLogger(IntroductionViewModel.class.getName());
+
+	private final ContactManager contactManager;
+	private final AuthorManager authorManager;
+	private final IntroductionManager introductionManager;
+
+	@Inject
+	IntroductionViewModel(Application application,
+			@DatabaseExecutor Executor dbExecutor,
+			LifecycleManager lifecycleManager, TransactionManager db,
+			AndroidExecutor androidExecutor, ContactManager contactManager,
+			AuthorManager authorManager,
+			ConversationManager conversationManager,
+			ConnectionRegistry connectionRegistry, EventBus eventBus,
+			IntroductionManager introductionManager) {
+		super(application, dbExecutor, lifecycleManager, db, androidExecutor,
+				contactManager, authorManager, conversationManager,
+				connectionRegistry, eventBus);
+		this.contactManager = contactManager;
+		this.authorManager = authorManager;
+		this.introductionManager = introductionManager;
+	}
+
+	/*
+	 * This is the contact from whose conversation we started the introduction
+	 * using the menu item.
+	 */
+	@Nullable
+	private ContactId firstContactId;
+	/*
+	 * This is the contact we selected from the list of contacts as a second
+	 * contact for the introduction.
+	 */
+	@Nullable
+	private ContactId secondContactId;
+
+	private final MutableLiveEvent<Boolean> secondContactSelected =
+			new MutableLiveEvent<>();
+
+	private final MutableLiveData<IntroductionInfo> introductionInfo =
+			new MutableLiveData<>();
+
+	void setFirstContactId(ContactId contactId) {
+		this.firstContactId = contactId;
+		loadContacts();
+	}
+
+	@Nullable
+	ContactId getSecondContactId() {
+		return secondContactId;
+	}
+
+	void setSecondContactId(ContactId contactId) {
+		secondContactId = contactId;
+		// Setting this to null here so that IntroductionMessageFragment can
+		// tell whether the correct value has been loaded from the database when
+		// selecting a second contact repeatedly.
+		introductionInfo.setValue(null);
+		loadIntroductionInfo();
+	}
+
+	/**
+	 * Trigger the event that the second contact has been selected from the
+	 * contact list by the user.
+	 */
+	void triggerContactSelected() {
+		secondContactSelected.setEvent(true);
+	}
+
+	/**
+	 * This event will be triggered once the second contact has been selected
+	 * from the list of contacts displayed. It is not fired when the second
+	 * contact gets restored from the saved instance state.
+	 */
+	LiveEvent<Boolean> getSecondContactSelected() {
+		return secondContactSelected;
+	}
+
+	/**
+	 * Holder for the introduction info object with data about both contacts
+	 * and whether the introduction is possible. May wrap null if the data
+	 * is not available yet. This happens when it is reset by selecting a
+	 * contact with the same view model instance more than once.
+	 */
+	LiveData<IntroductionInfo> getIntroductionInfo() {
+		return introductionInfo;
+	}
+
+	@Override
+	protected boolean displayContact(ContactId contactId) {
+		return !requireNonNull(firstContactId).equals(contactId);
+	}
+
+	private void loadIntroductionInfo() {
+		final ContactId firstContactId = requireNonNull(this.firstContactId);
+		final ContactId secondContactId = requireNonNull(this.secondContactId);
+		runOnDbThread(() -> {
+			try {
+				Contact firstContact =
+						contactManager.getContact(firstContactId);
+				Contact secondContact =
+						contactManager.getContact(secondContactId);
+				AuthorInfo a1 = authorManager.getAuthorInfo(firstContact);
+				AuthorInfo a2 = authorManager.getAuthorInfo(secondContact);
+				boolean possible = introductionManager
+						.canIntroduce(firstContact, secondContact);
+				ContactItem c1 = new ContactItem(firstContact, a1);
+				ContactItem c2 = new ContactItem(secondContact, a2);
+				introductionInfo.postValue(
+						new IntroductionInfo(c1, c2, possible));
+			} catch (DbException e) {
+				logException(LOG, WARNING, e);
+			}
+		});
+	}
+
+	void makeIntroduction(@Nullable String text) {
+		final IntroductionInfo info =
+				requireNonNull(introductionInfo.getValue());
+		runOnDbThread(() -> {
+			// actually make the introduction
+			try {
+				long timestamp = System.currentTimeMillis();
+				introductionManager.makeIntroduction(
+						info.getContact1().getContact(),
+						info.getContact2().getContact(), text, timestamp);
+			} catch (DbException e) {
+				logException(LOG, WARNING, e);
+				androidExecutor.runOnUiThread(() -> Toast.makeText(
+						getApplication(), R.string.introduction_error,
+						LENGTH_SHORT).show());
+			}
+		});
+	}
+
+}

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

@@ -1,119 +0,0 @@
-package org.briarproject.briar.android.keyagreement;
-
-import android.os.Bundle;
-import android.widget.Toast;
-
-import org.briarproject.bramble.api.identity.Author;
-import org.briarproject.bramble.api.keyagreement.KeyAgreementResult;
-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 javax.annotation.Nullable;
-import javax.inject.Inject;
-
-import androidx.annotation.UiThread;
-import androidx.lifecycle.ViewModelProvider;
-import androidx.lifecycle.ViewModelProviders;
-
-import static android.widget.Toast.LENGTH_LONG;
-import static java.util.Objects.requireNonNull;
-
-@MethodsNotNullByDefault
-@ParametersNotNullByDefault
-public class ContactExchangeActivity extends KeyAgreementActivity {
-
-	@Inject
-	ViewModelProvider.Factory viewModelFactory;
-
-	private ContactExchangeViewModel viewModel;
-
-	@Override
-	public void injectActivity(ActivityComponent component) {
-		component.inject(this);
-	}
-
-	@Override
-	public void onCreate(@Nullable Bundle state) {
-		super.onCreate(state);
-		requireNonNull(getSupportActionBar())
-				.setTitle(R.string.add_contact_title);
-		viewModel = ViewModelProviders.of(this, viewModelFactory)
-				.get(ContactExchangeViewModel.class);
-	}
-
-	private void startContactExchange(KeyAgreementResult result) {
-		viewModel.getSucceeded().observe(this, succeeded -> {
-			if (succeeded == null) return;
-			if (succeeded) {
-				Author remote = requireNonNull(viewModel.getRemoteAuthor());
-				contactExchangeSucceeded(remote);
-			} else {
-				Author duplicate = viewModel.getDuplicateAuthor();
-				if (duplicate == null) contactExchangeFailed();
-				else duplicateContact(duplicate);
-			}
-		});
-		viewModel.startContactExchange(result.getTransportId(),
-				result.getConnection(), result.getMasterKey(),
-				result.wasAlice());
-	}
-
-	@UiThread
-	private void contactExchangeSucceeded(Author remoteAuthor) {
-		String contactName = remoteAuthor.getName();
-		String text = getString(R.string.contact_added_toast, contactName);
-		Toast.makeText(this, text, LENGTH_LONG).show();
-		supportFinishAfterTransition();
-	}
-
-	@UiThread
-	private void duplicateContact(Author remoteAuthor) {
-		String contactName = remoteAuthor.getName();
-		String format = getString(R.string.contact_already_exists);
-		String text = String.format(format, contactName);
-		Toast.makeText(this, text, LENGTH_LONG).show();
-		finish();
-	}
-
-	@UiThread
-	private void contactExchangeFailed() {
-		showErrorFragment();
-	}
-
-	@UiThread
-	@Override
-	public void keyAgreementFailed() {
-		showErrorFragment();
-	}
-
-	@UiThread
-	@Override
-	public String keyAgreementWaiting() {
-		return getString(R.string.waiting_for_contact_to_scan);
-	}
-
-	@UiThread
-	@Override
-	public String keyAgreementStarted() {
-		return getString(R.string.authenticating_with_device);
-	}
-
-	@UiThread
-	@Override
-	public void keyAgreementAborted(boolean remoteAborted) {
-		showErrorFragment();
-	}
-
-	@UiThread
-	@Override
-	public String keyAgreementFinished(KeyAgreementResult result) {
-		startContactExchange(result);
-		return getString(R.string.exchanging_contact_details);
-	}
-
-	private void showErrorFragment() {
-		showNextFragment(new ContactExchangeErrorFragment());
-	}
-}

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

@@ -1,105 +0,0 @@
-package org.briarproject.briar.android.keyagreement;
-
-import android.app.Application;
-
-import org.briarproject.bramble.api.connection.ConnectionManager;
-import org.briarproject.bramble.api.contact.Contact;
-import org.briarproject.bramble.api.contact.ContactExchangeManager;
-import org.briarproject.bramble.api.crypto.SecretKey;
-import org.briarproject.bramble.api.db.ContactExistsException;
-import org.briarproject.bramble.api.db.DbException;
-import org.briarproject.bramble.api.identity.Author;
-import org.briarproject.bramble.api.lifecycle.IoExecutor;
-import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
-import org.briarproject.bramble.api.plugin.TransportId;
-import org.briarproject.bramble.api.plugin.duplex.DuplexTransportConnection;
-
-import java.io.IOException;
-import java.util.concurrent.Executor;
-import java.util.logging.Logger;
-
-import javax.annotation.Nullable;
-import javax.inject.Inject;
-
-import androidx.annotation.UiThread;
-import androidx.lifecycle.AndroidViewModel;
-import androidx.lifecycle.LiveData;
-import androidx.lifecycle.MutableLiveData;
-
-import static java.util.logging.Level.WARNING;
-import static java.util.logging.Logger.getLogger;
-import static org.briarproject.bramble.util.LogUtils.logException;
-
-@NotNullByDefault
-class ContactExchangeViewModel extends AndroidViewModel {
-
-	private static final Logger LOG =
-			getLogger(ContactExchangeViewModel.class.getName());
-
-	private final Executor ioExecutor;
-	private final ContactExchangeManager contactExchangeManager;
-	private final ConnectionManager connectionManager;
-	private final MutableLiveData<Boolean> succeeded = new MutableLiveData<>();
-
-	@Nullable
-	private volatile Author remoteAuthor, duplicateAuthor;
-
-	@Inject
-	ContactExchangeViewModel(Application app, @IoExecutor Executor ioExecutor,
-			ContactExchangeManager contactExchangeManager,
-			ConnectionManager connectionManager) {
-		super(app);
-		this.ioExecutor = ioExecutor;
-		this.contactExchangeManager = contactExchangeManager;
-		this.connectionManager = connectionManager;
-	}
-
-	@UiThread
-	void startContactExchange(TransportId t, DuplexTransportConnection conn,
-			SecretKey masterKey, boolean alice) {
-		ioExecutor.execute(() -> {
-			try {
-				Contact contact = contactExchangeManager.exchangeContacts(conn,
-						masterKey, alice, true);
-				// Reuse the connection as a transport connection
-				connectionManager.manageOutgoingConnection(contact.getId(),
-						t, conn);
-				remoteAuthor = contact.getAuthor();
-				succeeded.postValue(true);
-			} catch (ContactExistsException e) {
-				tryToClose(conn);
-				duplicateAuthor = e.getRemoteAuthor();
-				succeeded.postValue(false);
-			} catch (DbException | IOException e) {
-				tryToClose(conn);
-				logException(LOG, WARNING, e);
-				succeeded.postValue(false);
-			}
-		});
-	}
-
-	private void tryToClose(DuplexTransportConnection conn) {
-		try {
-			conn.getReader().dispose(true, true);
-			conn.getWriter().dispose(true);
-		} catch (IOException e) {
-			logException(LOG, WARNING, e);
-		}
-	}
-
-	@UiThread
-	@Nullable
-	Author getRemoteAuthor() {
-		return remoteAuthor;
-	}
-
-	@UiThread
-	@Nullable
-	Author getDuplicateAuthor() {
-		return duplicateAuthor;
-	}
-
-	LiveData<Boolean> getSucceeded() {
-		return succeeded;
-	}
-}

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

@@ -1,482 +0,0 @@
-package org.briarproject.briar.android.keyagreement;
-
-import android.bluetooth.BluetoothAdapter;
-import android.content.BroadcastReceiver;
-import android.content.Context;
-import android.content.Intent;
-import android.content.IntentFilter;
-import android.os.Bundle;
-import android.view.MenuItem;
-
-import org.briarproject.bramble.api.event.Event;
-import org.briarproject.bramble.api.event.EventBus;
-import org.briarproject.bramble.api.event.EventListener;
-import org.briarproject.bramble.api.nullsafety.MethodsNotNullByDefault;
-import org.briarproject.bramble.api.nullsafety.ParametersNotNullByDefault;
-import org.briarproject.bramble.api.plugin.BluetoothConstants;
-import org.briarproject.bramble.api.plugin.LanTcpConstants;
-import org.briarproject.bramble.api.plugin.Plugin;
-import org.briarproject.bramble.api.plugin.Plugin.State;
-import org.briarproject.bramble.api.plugin.PluginManager;
-import org.briarproject.bramble.api.plugin.event.TransportStateEvent;
-import org.briarproject.briar.R;
-import org.briarproject.briar.android.activity.ActivityComponent;
-import org.briarproject.briar.android.activity.BriarActivity;
-import org.briarproject.briar.android.fragment.BaseFragment;
-import org.briarproject.briar.android.fragment.BaseFragment.BaseFragmentListener;
-import org.briarproject.briar.android.keyagreement.IntroFragment.IntroScreenSeenListener;
-import org.briarproject.briar.android.keyagreement.KeyAgreementFragment.KeyAgreementEventListener;
-
-import java.util.logging.Logger;
-
-import javax.annotation.Nullable;
-import javax.inject.Inject;
-
-import androidx.annotation.StringRes;
-import androidx.annotation.UiThread;
-import androidx.appcompat.app.AlertDialog.Builder;
-import androidx.appcompat.widget.Toolbar;
-import androidx.core.app.ActivityCompat;
-import androidx.fragment.app.FragmentManager;
-
-import static android.Manifest.permission.ACCESS_FINE_LOCATION;
-import static android.Manifest.permission.CAMERA;
-import static android.bluetooth.BluetoothAdapter.ACTION_REQUEST_DISCOVERABLE;
-import static android.bluetooth.BluetoothAdapter.ACTION_SCAN_MODE_CHANGED;
-import static android.bluetooth.BluetoothAdapter.SCAN_MODE_CONNECTABLE_DISCOVERABLE;
-import static android.content.pm.PackageManager.PERMISSION_GRANTED;
-import static android.os.Build.VERSION.SDK_INT;
-import static java.util.logging.Level.INFO;
-import static java.util.logging.Logger.getLogger;
-import static org.briarproject.bramble.api.nullsafety.NullSafety.requireNonNull;
-import static org.briarproject.bramble.api.plugin.Plugin.State.ACTIVE;
-import static org.briarproject.bramble.api.plugin.Plugin.State.DISABLED;
-import static org.briarproject.bramble.api.plugin.Plugin.State.INACTIVE;
-import static org.briarproject.bramble.api.plugin.Plugin.State.STARTING_STOPPING;
-import static org.briarproject.briar.android.activity.RequestCodes.REQUEST_BLUETOOTH_DISCOVERABLE;
-import static org.briarproject.briar.android.activity.RequestCodes.REQUEST_PERMISSION_CAMERA_LOCATION;
-import static org.briarproject.briar.android.util.UiUtils.getGoToSettingsListener;
-
-@MethodsNotNullByDefault
-@ParametersNotNullByDefault
-public abstract class KeyAgreementActivity extends BriarActivity implements
-		BaseFragmentListener, IntroScreenSeenListener,
-		KeyAgreementEventListener, EventListener {
-
-	private enum BluetoothDecision {
-		/**
-		 * We haven't asked the user about Bluetooth discoverability.
-		 */
-		UNKNOWN,
-
-		/**
-		 * The device doesn't have a Bluetooth adapter.
-		 */
-		NO_ADAPTER,
-
-		/**
-		 * We're waiting for the user to accept or refuse discoverability.
-		 */
-		WAITING,
-
-		/**
-		 * The user has accepted discoverability.
-		 */
-		ACCEPTED,
-
-		/**
-		 * The user has refused discoverability.
-		 */
-		REFUSED
-	}
-
-	private enum Permission {
-		UNKNOWN, GRANTED, SHOW_RATIONALE, PERMANENTLY_DENIED
-	}
-
-	private static final Logger LOG =
-			getLogger(KeyAgreementActivity.class.getName());
-
-	@Inject
-	EventBus eventBus;
-
-	@Inject
-	PluginManager pluginManager;
-
-	/**
-	 * Set to true in onPostResume() and false in onPause(). This prevents the
-	 * QR code fragment from being shown if onRequestPermissionsResult() is
-	 * called while the activity is paused, which could cause a crash due to
-	 * https://issuetracker.google.com/issues/37067655.
-	 */
-	private boolean isResumed = false;
-
-	/**
-	 * Set to true when the continue button is clicked, and false when the QR
-	 * code fragment is shown. This prevents the QR code fragment from being
-	 * shown automatically before the continue button has been clicked.
-	 */
-	private boolean continueClicked = false;
-
-	/**
-	 * Records whether we've enabled the wifi plugin so we don't enable it more
-	 * than once.
-	 */
-	private boolean hasEnabledWifi = false;
-
-	/**
-	 * Records whether we've enabled the Bluetooth plugin so we don't enable it
-	 * more than once.
-	 */
-	private boolean hasEnabledBluetooth = false;
-
-	private Permission cameraPermission = Permission.UNKNOWN;
-	private Permission locationPermission = Permission.UNKNOWN;
-	private BluetoothDecision bluetoothDecision = BluetoothDecision.UNKNOWN;
-	private BroadcastReceiver bluetoothReceiver = null;
-	private Plugin wifiPlugin = null, bluetoothPlugin = null;
-	private BluetoothAdapter bt = null;
-
-	@Override
-	public void injectActivity(ActivityComponent component) {
-		component.inject(this);
-	}
-
-	@Override
-	public void onCreate(@Nullable Bundle state) {
-		super.onCreate(state);
-		setContentView(R.layout.activity_fragment_container_toolbar);
-		Toolbar toolbar = findViewById(R.id.toolbar);
-		setSupportActionBar(toolbar);
-		requireNonNull(getSupportActionBar()).setDisplayHomeAsUpEnabled(true);
-		if (state == null) {
-			showInitialFragment(IntroFragment.newInstance());
-		}
-		IntentFilter filter = new IntentFilter(ACTION_SCAN_MODE_CHANGED);
-		bluetoothReceiver = new BluetoothStateReceiver();
-		registerReceiver(bluetoothReceiver, filter);
-		wifiPlugin = pluginManager.getPlugin(LanTcpConstants.ID);
-		bluetoothPlugin = pluginManager.getPlugin(BluetoothConstants.ID);
-		bt = BluetoothAdapter.getDefaultAdapter();
-	}
-
-	@Override
-	public void onDestroy() {
-		super.onDestroy();
-		if (bluetoothReceiver != null) unregisterReceiver(bluetoothReceiver);
-	}
-
-	@Override
-	public boolean onOptionsItemSelected(MenuItem item) {
-		if (item.getItemId() == android.R.id.home) {
-			onBackPressed();
-			return true;
-		}
-		return super.onOptionsItemSelected(item);
-	}
-
-	@Override
-	public void onStart() {
-		super.onStart();
-		eventBus.addListener(this);
-		// Permissions may have been granted manually while we were stopped
-		cameraPermission = Permission.UNKNOWN;
-		locationPermission = Permission.UNKNOWN;
-	}
-
-	@Override
-	protected void onPostResume() {
-		super.onPostResume();
-		isResumed = true;
-		// Workaround for
-		// https://code.google.com/p/android/issues/detail?id=190966
-		showQrCodeFragmentIfAllowed();
-	}
-
-	@SuppressWarnings("StatementWithEmptyBody")
-	private void showQrCodeFragmentIfAllowed() {
-		if (isResumed && continueClicked && areEssentialPermissionsGranted()) {
-			if (isWifiReady() && isBluetoothReady()) {
-				LOG.info("Wifi and Bluetooth are ready");
-				showQrCodeFragment();
-			} else {
-				if (shouldEnableWifi()) {
-					LOG.info("Enabling wifi plugin");
-					hasEnabledWifi = true;
-					pluginManager.setPluginEnabled(LanTcpConstants.ID, true);
-				}
-				if (bluetoothDecision == BluetoothDecision.UNKNOWN) {
-					requestBluetoothDiscoverable();
-				} else if (bluetoothDecision == BluetoothDecision.REFUSED) {
-					// Ask again when the user clicks "continue"
-				} else if (shouldEnableBluetooth()) {
-					LOG.info("Enabling Bluetooth plugin");
-					hasEnabledBluetooth = true;
-					pluginManager.setPluginEnabled(BluetoothConstants.ID, true);
-				}
-			}
-		}
-	}
-
-	private boolean areEssentialPermissionsGranted() {
-		return cameraPermission == Permission.GRANTED &&
-				(SDK_INT < 23 || locationPermission == Permission.GRANTED ||
-						!isBluetoothSupported());
-	}
-
-	private boolean isBluetoothSupported() {
-		return bt != null && bluetoothPlugin != null;
-	}
-
-	private boolean isWifiReady() {
-		if (wifiPlugin == null) return true; // Continue without wifi
-		State state = wifiPlugin.getState();
-		// Wait for plugin to become enabled
-		return state == ACTIVE || state == INACTIVE;
-	}
-
-	private boolean isBluetoothReady() {
-		if (!isBluetoothSupported()) {
-			// Continue without Bluetooth
-			return true;
-		}
-		if (bluetoothDecision == BluetoothDecision.UNKNOWN ||
-				bluetoothDecision == BluetoothDecision.WAITING ||
-				bluetoothDecision == BluetoothDecision.REFUSED) {
-			// Wait for user to accept
-			return false;
-		}
-		if (bt.getScanMode() != SCAN_MODE_CONNECTABLE_DISCOVERABLE) {
-			// Wait for adapter to become discoverable
-			return false;
-		}
-		// Wait for plugin to become active
-		return bluetoothPlugin.getState() == ACTIVE;
-	}
-
-	private boolean shouldEnableWifi() {
-		if (hasEnabledWifi) return false;
-		if (wifiPlugin == null) return false;
-		State state = wifiPlugin.getState();
-		return state == STARTING_STOPPING || state == DISABLED;
-	}
-
-	private void requestBluetoothDiscoverable() {
-		if (!isBluetoothSupported()) {
-			bluetoothDecision = BluetoothDecision.NO_ADAPTER;
-			showQrCodeFragmentIfAllowed();
-		} else {
-			Intent i = new Intent(ACTION_REQUEST_DISCOVERABLE);
-			if (i.resolveActivity(getPackageManager()) != null) {
-				LOG.info("Asking for Bluetooth discoverability");
-				bluetoothDecision = BluetoothDecision.WAITING;
-				startActivityForResult(i, REQUEST_BLUETOOTH_DISCOVERABLE);
-			} else {
-				bluetoothDecision = BluetoothDecision.NO_ADAPTER;
-				showQrCodeFragmentIfAllowed();
-			}
-		}
-	}
-
-	private boolean shouldEnableBluetooth() {
-		if (bluetoothDecision != BluetoothDecision.ACCEPTED) return false;
-		if (hasEnabledBluetooth) return false;
-		if (!isBluetoothSupported()) return false;
-		State state = bluetoothPlugin.getState();
-		return state == STARTING_STOPPING || state == DISABLED;
-	}
-
-	@Override
-	protected void onPause() {
-		super.onPause();
-		isResumed = false;
-	}
-
-	@Override
-	protected void onStop() {
-		super.onStop();
-		eventBus.removeListener(this);
-	}
-
-	@Override
-	public void showNextScreen() {
-		continueClicked = true;
-		if (bluetoothDecision == BluetoothDecision.REFUSED) {
-			bluetoothDecision = BluetoothDecision.UNKNOWN; // Ask again
-		}
-		if (checkPermissions()) showQrCodeFragmentIfAllowed();
-	}
-
-	@Override
-	public void onActivityResult(int request, int result,
-			@Nullable Intent data) {
-		if (request == REQUEST_BLUETOOTH_DISCOVERABLE) {
-			if (result == RESULT_CANCELED) {
-				LOG.info("Bluetooth discoverability was refused");
-				bluetoothDecision = BluetoothDecision.REFUSED;
-			} else {
-				LOG.info("Bluetooth discoverability was accepted");
-				bluetoothDecision = BluetoothDecision.ACCEPTED;
-			}
-			showQrCodeFragmentIfAllowed();
-		} else super.onActivityResult(request, result, data);
-	}
-
-	private void showQrCodeFragment() {
-		// If we return to the intro fragment, the continue button needs to be
-		// clicked again before showing the QR code fragment
-		continueClicked = false;
-		// If we return to the intro fragment, ask for Bluetooth
-		// discoverability again before showing the QR code fragment
-		bluetoothDecision = BluetoothDecision.UNKNOWN;
-		// If we return to the intro fragment, we may need to enable wifi and
-		// Bluetooth again
-		hasEnabledWifi = false;
-		hasEnabledBluetooth = false;
-
-		// FIXME #824
-		FragmentManager fm = getSupportFragmentManager();
-		if (fm.findFragmentByTag(KeyAgreementFragment.TAG) == null) {
-			BaseFragment f = KeyAgreementFragment.newInstance();
-			fm.beginTransaction()
-					.replace(R.id.fragmentContainer, f, f.getUniqueTag())
-					.addToBackStack(f.getUniqueTag())
-					.commit();
-		}
-	}
-
-	private boolean checkPermissions() {
-		if (areEssentialPermissionsGranted()) return true;
-		// If an essential permission has been permanently denied, ask the
-		// user to change the setting
-		if (cameraPermission == Permission.PERMANENTLY_DENIED) {
-			showDenialDialog(R.string.permission_camera_title,
-					R.string.permission_camera_denied_body);
-			return false;
-		}
-		if (isBluetoothSupported() &&
-				locationPermission == Permission.PERMANENTLY_DENIED) {
-			showDenialDialog(R.string.permission_location_title,
-					R.string.permission_location_denied_body);
-			return false;
-		}
-		// Should we show the rationale for one or both permissions?
-		if (cameraPermission == Permission.SHOW_RATIONALE &&
-				locationPermission == Permission.SHOW_RATIONALE) {
-			showRationale(R.string.permission_camera_location_title,
-					R.string.permission_camera_location_request_body);
-		} else if (cameraPermission == Permission.SHOW_RATIONALE) {
-			showRationale(R.string.permission_camera_title,
-					R.string.permission_camera_request_body);
-		} else if (locationPermission == Permission.SHOW_RATIONALE) {
-			showRationale(R.string.permission_location_title,
-					R.string.permission_location_request_body);
-		} else {
-			requestPermissions();
-		}
-		return false;
-	}
-
-	private void showDenialDialog(@StringRes int title, @StringRes int body) {
-		Builder builder = new Builder(this, R.style.BriarDialogTheme);
-		builder.setTitle(title);
-		builder.setMessage(body);
-		builder.setPositiveButton(R.string.ok, getGoToSettingsListener(this));
-		builder.setNegativeButton(R.string.cancel,
-				(dialog, which) -> supportFinishAfterTransition());
-		builder.show();
-	}
-
-	private void showRationale(@StringRes int title, @StringRes int body) {
-		Builder builder = new Builder(this, R.style.BriarDialogTheme);
-		builder.setTitle(title);
-		builder.setMessage(body);
-		builder.setNeutralButton(R.string.continue_button,
-				(dialog, which) -> requestPermissions());
-		builder.show();
-	}
-
-	private void requestPermissions() {
-		String[] permissions;
-		if (isBluetoothSupported()) {
-			permissions = new String[] {CAMERA, ACCESS_FINE_LOCATION};
-		} else {
-			permissions = new String[] {CAMERA};
-		}
-		ActivityCompat.requestPermissions(this, permissions,
-				REQUEST_PERMISSION_CAMERA_LOCATION);
-	}
-
-	@Override
-	@UiThread
-	public void onRequestPermissionsResult(int requestCode,
-			String[] permissions, int[] grantResults) {
-		if (requestCode != REQUEST_PERMISSION_CAMERA_LOCATION)
-			throw new AssertionError();
-		if (gotPermission(CAMERA, permissions, grantResults)) {
-			cameraPermission = Permission.GRANTED;
-		} else if (shouldShowRationale(CAMERA)) {
-			cameraPermission = Permission.SHOW_RATIONALE;
-		} else {
-			cameraPermission = Permission.PERMANENTLY_DENIED;
-		}
-		if (isBluetoothSupported()) {
-			if (gotPermission(ACCESS_FINE_LOCATION, permissions,
-					grantResults)) {
-				locationPermission = Permission.GRANTED;
-			} else if (shouldShowRationale(ACCESS_FINE_LOCATION)) {
-				locationPermission = Permission.SHOW_RATIONALE;
-			} else {
-				locationPermission = Permission.PERMANENTLY_DENIED;
-			}
-		}
-		// If a permission dialog has been shown, showing the QR code fragment
-		// on this call path would cause a crash due to
-		// https://code.google.com/p/android/issues/detail?id=190966.
-		// In that case the isResumed flag prevents the fragment from being
-		// shown here, and showQrCodeFragmentIfAllowed() will be called again
-		// from onPostResume().
-		if (checkPermissions()) showQrCodeFragmentIfAllowed();
-	}
-
-	private boolean gotPermission(String permission, String[] permissions,
-			int[] grantResults) {
-		for (int i = 0; i < permissions.length; i++) {
-			if (permission.equals(permissions[i]))
-				return grantResults[i] == PERMISSION_GRANTED;
-		}
-		return false;
-	}
-
-	private boolean shouldShowRationale(String permission) {
-		return ActivityCompat.shouldShowRequestPermissionRationale(this,
-				permission);
-	}
-
-	@Override
-	public void eventOccurred(Event e) {
-		if (e instanceof TransportStateEvent) {
-			TransportStateEvent t = (TransportStateEvent) e;
-			if (t.getTransportId().equals(BluetoothConstants.ID)) {
-				if (LOG.isLoggable(INFO)) {
-					LOG.info("Bluetooth state changed to " + t.getState());
-				}
-				showQrCodeFragmentIfAllowed();
-			} else if (t.getTransportId().equals(LanTcpConstants.ID)) {
-				if (LOG.isLoggable(INFO)) {
-					LOG.info("Wifi state changed to " + t.getState());
-				}
-				showQrCodeFragmentIfAllowed();
-			}
-		}
-	}
-
-	private class BluetoothStateReceiver extends BroadcastReceiver {
-
-		@Override
-		public void onReceive(Context context, Intent intent) {
-			LOG.info("Bluetooth scan mode changed");
-			showQrCodeFragmentIfAllowed();
-		}
-	}
-}

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

@@ -1,375 +0,0 @@
-package org.briarproject.briar.android.keyagreement;
-
-import android.content.Context;
-import android.graphics.Bitmap;
-import android.os.Bundle;
-import android.util.DisplayMetrics;
-import android.view.LayoutInflater;
-import android.view.View;
-import android.view.ViewGroup;
-import android.widget.LinearLayout;
-import android.widget.LinearLayout.LayoutParams;
-import android.widget.TextView;
-import android.widget.Toast;
-
-import com.google.zxing.Result;
-
-import org.briarproject.bramble.api.UnsupportedVersionException;
-import org.briarproject.bramble.api.event.Event;
-import org.briarproject.bramble.api.event.EventBus;
-import org.briarproject.bramble.api.keyagreement.KeyAgreementResult;
-import org.briarproject.bramble.api.keyagreement.KeyAgreementTask;
-import org.briarproject.bramble.api.keyagreement.Payload;
-import org.briarproject.bramble.api.keyagreement.PayloadEncoder;
-import org.briarproject.bramble.api.keyagreement.PayloadParser;
-import org.briarproject.bramble.api.keyagreement.event.KeyAgreementAbortedEvent;
-import org.briarproject.bramble.api.keyagreement.event.KeyAgreementFailedEvent;
-import org.briarproject.bramble.api.keyagreement.event.KeyAgreementFinishedEvent;
-import org.briarproject.bramble.api.keyagreement.event.KeyAgreementListeningEvent;
-import org.briarproject.bramble.api.keyagreement.event.KeyAgreementStartedEvent;
-import org.briarproject.bramble.api.keyagreement.event.KeyAgreementWaitingEvent;
-import org.briarproject.bramble.api.lifecycle.IoExecutor;
-import org.briarproject.bramble.api.nullsafety.MethodsNotNullByDefault;
-import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
-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.BaseEventFragment;
-import org.briarproject.briar.android.view.QrCodeView;
-
-import java.io.IOException;
-import java.nio.charset.Charset;
-import java.util.concurrent.Executor;
-import java.util.logging.Logger;
-
-import javax.annotation.Nullable;
-import javax.inject.Inject;
-import javax.inject.Provider;
-
-import androidx.annotation.UiThread;
-
-import static android.content.pm.ActivityInfo.SCREEN_ORIENTATION_NOSENSOR;
-import static android.view.View.INVISIBLE;
-import static android.view.View.VISIBLE;
-import static android.view.ViewGroup.LayoutParams.MATCH_PARENT;
-import static android.widget.LinearLayout.HORIZONTAL;
-import static android.widget.Toast.LENGTH_LONG;
-import static java.util.logging.Level.INFO;
-import static java.util.logging.Level.WARNING;
-import static org.briarproject.bramble.util.LogUtils.logException;
-
-@MethodsNotNullByDefault
-@ParametersNotNullByDefault
-public class KeyAgreementFragment extends BaseEventFragment
-		implements QrCodeDecoder.ResultCallback, QrCodeView.FullscreenListener {
-
-	static final String TAG = KeyAgreementFragment.class.getName();
-
-	private static final Logger LOG = Logger.getLogger(TAG);
-	@SuppressWarnings("CharsetObjectCanBeUsed") // Requires minSdkVersion >= 19
-	private static final Charset ISO_8859_1 = Charset.forName("ISO-8859-1");
-
-	@Inject
-	Provider<KeyAgreementTask> keyAgreementTaskProvider;
-	@Inject
-	PayloadEncoder payloadEncoder;
-	@Inject
-	PayloadParser payloadParser;
-	@Inject
-	@IoExecutor
-	Executor ioExecutor;
-	@Inject
-	EventBus eventBus;
-
-	private CameraView cameraView;
-	private LinearLayout cameraOverlay;
-	private View statusView;
-	private QrCodeView qrCodeView;
-	private TextView status;
-
-	private boolean gotRemotePayload;
-	private volatile boolean gotLocalPayload;
-	private KeyAgreementTask task;
-	private KeyAgreementEventListener listener;
-
-	public static KeyAgreementFragment newInstance() {
-		Bundle args = new Bundle();
-		KeyAgreementFragment fragment = new KeyAgreementFragment();
-		fragment.setArguments(args);
-		return fragment;
-	}
-
-	@Override
-	public void onAttach(Context context) {
-		super.onAttach(context);
-		listener = (KeyAgreementEventListener) context;
-	}
-
-	@Override
-	public void injectFragment(ActivityComponent component) {
-		component.inject(this);
-	}
-
-	@Override
-	public String getUniqueTag() {
-		return TAG;
-	}
-
-	@Nullable
-	@Override
-	public View onCreateView(LayoutInflater inflater,
-			@Nullable ViewGroup container,
-			@Nullable Bundle savedInstanceState) {
-		return inflater.inflate(R.layout.fragment_keyagreement_qr, container,
-				false);
-	}
-
-	@Override
-	public void onViewCreated(View view, @Nullable Bundle savedInstanceState) {
-		super.onViewCreated(view, savedInstanceState);
-		cameraView = view.findViewById(R.id.camera_view);
-		cameraOverlay = view.findViewById(R.id.camera_overlay);
-		statusView = view.findViewById(R.id.status_container);
-		status = view.findViewById(R.id.connect_status);
-		qrCodeView = view.findViewById(R.id.qr_code_view);
-		qrCodeView.setFullscreenListener(this);
-	}
-
-	@Override
-	public void onActivityCreated(@Nullable Bundle savedInstanceState) {
-		super.onActivityCreated(savedInstanceState);
-		requireActivity().setRequestedOrientation(SCREEN_ORIENTATION_NOSENSOR);
-		cameraView.setPreviewConsumer(new QrCodeDecoder(this));
-	}
-
-	@Override
-	public void onStart() {
-		super.onStart();
-		try {
-			cameraView.start();
-		} catch (CameraException e) {
-			logCameraExceptionAndFinish(e);
-		}
-		startListening();
-	}
-
-	@Override
-	public void setFullscreen(boolean fullscreen) {
-		LinearLayout.LayoutParams statusParams, qrCodeParams;
-		if (fullscreen) {
-			// Grow the QR code view to fill its parent
-			statusParams = new LayoutParams(0, 0, 0f);
-			qrCodeParams = new LayoutParams(MATCH_PARENT, MATCH_PARENT, 1f);
-		} else {
-			// Shrink the QR code view to fill half its parent
-			if (cameraOverlay.getOrientation() == HORIZONTAL) {
-				statusParams = new LayoutParams(0, MATCH_PARENT, 1f);
-				qrCodeParams = new LayoutParams(0, MATCH_PARENT, 1f);
-			} else {
-				statusParams = new LayoutParams(MATCH_PARENT, 0, 1f);
-				qrCodeParams = new LayoutParams(MATCH_PARENT, 0, 1f);
-			}
-		}
-		statusView.setLayoutParams(statusParams);
-		qrCodeView.setLayoutParams(qrCodeParams);
-		cameraOverlay.invalidate();
-	}
-
-	@Override
-	public void onStop() {
-		super.onStop();
-		stopListening();
-		try {
-			cameraView.stop();
-		} catch (CameraException e) {
-			logCameraExceptionAndFinish(e);
-		}
-	}
-
-	@UiThread
-	private void logCameraExceptionAndFinish(CameraException e) {
-		logException(LOG, WARNING, e);
-		Toast.makeText(getActivity(), R.string.camera_error,
-				LENGTH_LONG).show();
-		finish();
-	}
-
-	@UiThread
-	private void startListening() {
-		KeyAgreementTask oldTask = task;
-		KeyAgreementTask newTask = keyAgreementTaskProvider.get();
-		task = newTask;
-		ioExecutor.execute(() -> {
-			if (oldTask != null) oldTask.stopListening();
-			newTask.listen();
-		});
-	}
-
-	@UiThread
-	private void stopListening() {
-		KeyAgreementTask oldTask = task;
-		ioExecutor.execute(() -> {
-			if (oldTask != null) oldTask.stopListening();
-		});
-	}
-
-	@UiThread
-	private void reset() {
-		// If we've stopped the camera view, restart it
-		if (gotRemotePayload) {
-			try {
-				cameraView.start();
-			} catch (CameraException e) {
-				logCameraExceptionAndFinish(e);
-				return;
-			}
-		}
-		statusView.setVisibility(INVISIBLE);
-		cameraView.setVisibility(VISIBLE);
-		gotRemotePayload = false;
-		gotLocalPayload = false;
-		startListening();
-	}
-
-	@UiThread
-	private void qrCodeScanned(String content) {
-		try {
-			byte[] payloadBytes = content.getBytes(ISO_8859_1);
-			if (LOG.isLoggable(INFO))
-				LOG.info("Remote payload is " + payloadBytes.length + " bytes");
-			Payload remotePayload = payloadParser.parse(payloadBytes);
-			gotRemotePayload = true;
-			cameraView.stop();
-			cameraView.setVisibility(INVISIBLE);
-			statusView.setVisibility(VISIBLE);
-			status.setText(R.string.connecting_to_device);
-			task.connectAndRunProtocol(remotePayload);
-		} catch (UnsupportedVersionException e) {
-			reset();
-			String msg;
-			if (e.isTooOld()) {
-				msg = getString(R.string.qr_code_too_old,
-						getString(R.string.app_name));
-			} else {
-				msg = getString(R.string.qr_code_too_new,
-						getString(R.string.app_name));
-			}
-			showNextFragment(ContactExchangeErrorFragment.newInstance(msg));
-		} catch (CameraException e) {
-			logCameraExceptionAndFinish(e);
-		} catch (IOException | IllegalArgumentException e) {
-			LOG.log(WARNING, "QR Code Invalid", e);
-			reset();
-			Toast.makeText(getActivity(), R.string.qr_code_invalid,
-					LENGTH_LONG).show();
-		}
-	}
-
-	@Override
-	public void eventOccurred(Event e) {
-		if (e instanceof KeyAgreementListeningEvent) {
-			KeyAgreementListeningEvent event = (KeyAgreementListeningEvent) e;
-			gotLocalPayload = true;
-			setQrCode(event.getLocalPayload());
-		} else if (e instanceof KeyAgreementFailedEvent) {
-			keyAgreementFailed();
-		} else if (e instanceof KeyAgreementWaitingEvent) {
-			keyAgreementWaiting();
-		} else if (e instanceof KeyAgreementStartedEvent) {
-			keyAgreementStarted();
-		} else if (e instanceof KeyAgreementAbortedEvent) {
-			KeyAgreementAbortedEvent event = (KeyAgreementAbortedEvent) e;
-			keyAgreementAborted(event.didRemoteAbort());
-		} else if (e instanceof KeyAgreementFinishedEvent) {
-			keyAgreementFinished(((KeyAgreementFinishedEvent) e).getResult());
-		}
-	}
-
-	@UiThread
-	private void keyAgreementFailed() {
-		reset();
-		listener.keyAgreementFailed();
-	}
-
-	@UiThread
-	private void keyAgreementWaiting() {
-		status.setText(listener.keyAgreementWaiting());
-	}
-
-	@UiThread
-	private void keyAgreementStarted() {
-		qrCodeView.setVisibility(INVISIBLE);
-		statusView.setVisibility(VISIBLE);
-		status.setText(listener.keyAgreementStarted());
-	}
-
-	@UiThread
-	private void keyAgreementAborted(boolean remoteAborted) {
-		reset();
-		listener.keyAgreementAborted(remoteAborted);
-	}
-
-	@UiThread
-	private void keyAgreementFinished(KeyAgreementResult result) {
-		statusView.setVisibility(VISIBLE);
-		status.setText(listener.keyAgreementFinished(result));
-	}
-
-	private void setQrCode(Payload localPayload) {
-		Context context = getContext();
-		if (context == null) return;
-		DisplayMetrics dm = context.getResources().getDisplayMetrics();
-		ioExecutor.execute(() -> {
-			byte[] payloadBytes = payloadEncoder.encode(localPayload);
-			if (LOG.isLoggable(INFO)) {
-				LOG.info("Local payload is " + payloadBytes.length
-						+ " bytes");
-			}
-			// Use ISO 8859-1 to encode bytes directly as a string
-			String content = new String(payloadBytes, ISO_8859_1);
-			Bitmap qrCode = QrCodeUtils.createQrCode(dm, content);
-			runOnUiThreadUnlessDestroyed(() -> qrCodeView.setQrCode(qrCode));
-		});
-	}
-
-	@Override
-	public void handleResult(Result result) {
-		runOnUiThreadUnlessDestroyed(() -> {
-			LOG.info("Got result from decoder");
-			// Ignore results until the KeyAgreementTask is ready
-			if (!gotLocalPayload) return;
-			if (!gotRemotePayload) qrCodeScanned(result.getText());
-		});
-	}
-
-	@Override
-	protected void finish() {
-		getActivity().getSupportFragmentManager().popBackStack();
-	}
-
-	@NotNullByDefault
-	interface KeyAgreementEventListener {
-
-		@UiThread
-		void keyAgreementFailed();
-
-		// Should return a string to be displayed as status.
-		@UiThread
-		@Nullable
-		String keyAgreementWaiting();
-
-		// Should return a string to be displayed as status.
-		@UiThread
-		@Nullable
-		String keyAgreementStarted();
-
-		// Will show an error fragment.
-		@UiThread
-		void keyAgreementAborted(boolean remoteAborted);
-
-		// Should return a string to be displayed as status.
-		@UiThread
-		@Nullable
-		String keyAgreementFinished(KeyAgreementResult result);
-	}
-}

briar-android/src/main/java/org/briarproject/briar/android/navdrawer/NavDrawerActivity.java

@@ -49,14 +49,12 @@ import androidx.annotation.DrawableRes;
 import androidx.annotation.NonNull;
 import androidx.annotation.Nullable;
 import androidx.annotation.StringRes;
-import androidx.appcompat.app.ActionBar;
 import androidx.appcompat.app.ActionBarDrawerToggle;
 import androidx.appcompat.widget.Toolbar;
 import androidx.core.app.ActivityCompat;
 import androidx.core.content.ContextCompat;
 import androidx.drawerlayout.widget.DrawerLayout;
 import androidx.fragment.app.FragmentManager;
-import androidx.fragment.app.FragmentTransaction;
 import androidx.lifecycle.MutableLiveData;
 import androidx.lifecycle.ViewModelProvider;
 import androidx.lifecycle.ViewModelProviders;
@@ -67,9 +65,7 @@ import static android.view.View.GONE;
 import static android.view.View.VISIBLE;
 import static androidx.core.view.GravityCompat.START;
 import static androidx.drawerlayout.widget.DrawerLayout.LOCK_MODE_LOCKED_CLOSED;
-import static androidx.fragment.app.FragmentManager.POP_BACK_STACK_INCLUSIVE;
 import static androidx.lifecycle.Lifecycle.State.STARTED;
-import static java.util.Objects.requireNonNull;
 import static java.util.logging.Logger.getLogger;
 import static org.briarproject.bramble.api.lifecycle.LifecycleManager.LifecycleState.RUNNING;
 import static org.briarproject.bramble.api.plugin.Plugin.State.ACTIVE;
@@ -146,7 +142,7 @@ public class NavDrawerActivity extends BriarActivity implements
 			if (ask) showDozeDialog(getString(R.string.setup_doze_intro));
 		});
 
-		Toolbar toolbar = findViewById(R.id.toolbar);
+		Toolbar toolbar = setUpCustomToolbar(false);
 		drawerLayout = findViewById(R.id.drawer_layout);
 		navigation = findViewById(R.id.navigation);
 		GridView transportsView = findViewById(R.id.transportsView);
@@ -156,11 +152,6 @@ public class NavDrawerActivity extends BriarActivity implements
 			startActivity(new Intent(this, TransportsActivity.class));
 		});
 
-		setSupportActionBar(toolbar);
-		ActionBar actionBar = requireNonNull(getSupportActionBar());
-		actionBar.setDisplayHomeAsUpEnabled(true);
-		actionBar.setHomeButtonEnabled(true);
-
 		drawerToggle = new ActionBarDrawerToggle(this, drawerLayout, toolbar,
 				R.string.nav_drawer_open_description,
 				R.string.nav_drawer_close_description) {
@@ -184,9 +175,6 @@ public class NavDrawerActivity extends BriarActivity implements
 
 		if (lifecycleManager.getLifecycleState().isAfter(RUNNING)) {
 			showSignOutFragment();
-		} else if (state == null) {
-			startFragment(ContactListFragment.newInstance(),
-					R.id.nav_btn_contacts);
 		}
 		if (state == null) {
 			// do not call this again when there's existing state
@@ -276,7 +264,6 @@ public class NavDrawerActivity extends BriarActivity implements
 	@Override
 	public boolean onNavigationItemSelected(@NonNull MenuItem item) {
 		drawerLayout.closeDrawer(START);
-		clearBackStack();
 		if (item.getItemId() == R.id.nav_btn_lock) {
 			lockManager.setLocked(true);
 			ActivityCompat.finishAfterTransition(this);
@@ -296,8 +283,8 @@ public class NavDrawerActivity extends BriarActivity implements
 			FragmentManager fm = getSupportFragmentManager();
 			if (fm.findFragmentByTag(SignOutFragment.TAG) != null) {
 				finish();
-			} else if (fm.getBackStackEntryCount() == 0
+			} else if (fm.getBackStackEntryCount() == 0 &&
-					&& fm.findFragmentByTag(ContactListFragment.TAG) == null) {
+					fm.findFragmentByTag(ContactListFragment.TAG) == null) {
 				// don't start fragments in the wrong part of lifecycle (#1904)
 				if (!getLifecycle().getCurrentState().isAtLeast(STARTED)) {
 					LOG.warning("Tried to start contacts fragment in state " +
@@ -346,30 +333,12 @@ public class NavDrawerActivity extends BriarActivity implements
 		startFragment(fragment);
 	}
 
-	private void startFragment(BaseFragment fragment) {
+	private void startFragment(BaseFragment f) {
-		if (getSupportFragmentManager().getBackStackEntryCount() == 0)
+		getSupportFragmentManager().beginTransaction()
-			startFragment(fragment, false);
+				.setCustomAnimations(R.anim.fade_in, R.anim.fade_out,
-		else startFragment(fragment, true);
+						R.anim.fade_in, R.anim.fade_out)
-	}
+				.replace(R.id.fragmentContainer, f, f.getUniqueTag())
-
+				.commit();
-	private void startFragment(BaseFragment fragment,
-			boolean isAddedToBackStack) {
-		FragmentTransaction trans =
-				getSupportFragmentManager().beginTransaction()
-						.setCustomAnimations(R.anim.fade_in,
-								R.anim.fade_out, R.anim.fade_in,
-								R.anim.fade_out)
-						.replace(R.id.fragmentContainer, fragment,
-								fragment.getUniqueTag());
-		if (isAddedToBackStack) {
-			trans.addToBackStack(fragment.getUniqueTag());
-		}
-		trans.commit();
-	}
-
-	private void clearBackStack() {
-		getSupportFragmentManager().popBackStackImmediate(null,
-				POP_BACK_STACK_INCLUSIVE);
 	}
 
 	@Override

briar-android/src/main/java/org/briarproject/briar/android/privategroup/reveal/RevealContactsFragment.java

@@ -8,7 +8,7 @@ import org.briarproject.bramble.api.nullsafety.MethodsNotNullByDefault;
 import org.briarproject.bramble.api.nullsafety.ParametersNotNullByDefault;
 import org.briarproject.bramble.api.sync.GroupId;
 import org.briarproject.briar.android.activity.ActivityComponent;
-import org.briarproject.briar.android.contact.BaseContactListAdapter.OnContactClickListener;
+import org.briarproject.briar.android.contact.OnContactClickListener;
 import org.briarproject.briar.android.contactselection.BaseContactSelectorFragment;
 import org.briarproject.briar.android.contactselection.ContactSelectorController;
 

briar-android/src/main/java/org/briarproject/briar/android/privategroup/reveal/RevealableContactAdapter.java

@@ -8,6 +8,7 @@ import android.view.ViewGroup;
 import org.briarproject.bramble.api.contact.ContactId;
 import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
 import org.briarproject.briar.R;
+import org.briarproject.briar.android.contact.OnContactClickListener;
 import org.briarproject.briar.android.contactselection.BaseContactSelectorAdapter;
 
 import java.util.ArrayList;

briar-android/src/main/java/org/briarproject/briar/android/privategroup/reveal/RevealableContactViewHolder.java

@@ -5,7 +5,7 @@ import android.widget.ImageView;
 
 import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
 import org.briarproject.briar.R;
-import org.briarproject.briar.android.contact.BaseContactListAdapter.OnContactClickListener;
+import org.briarproject.briar.android.contact.OnContactClickListener;
 import org.briarproject.briar.android.contactselection.BaseSelectableContactHolder;
 
 import javax.annotation.Nullable;

briar-android/src/main/java/org/briarproject/briar/android/settings/ConfirmAvatarDialogFragment.java

@@ -9,10 +9,13 @@ import android.view.View;
 import android.widget.ImageView;
 import android.widget.TextView;
 
+import com.bumptech.glide.load.engine.DiskCacheStrategy;
+
 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.BaseActivity;
+import org.briarproject.briar.android.conversation.glide.GlideApp;
 
 import javax.inject.Inject;
 
@@ -32,7 +35,7 @@ public class ConfirmAvatarDialogFragment extends DialogFragment {
 
 	@Inject
 	ViewModelProvider.Factory viewModelFactory;
-	private SettingsViewModel settingsViewModel;
+	private SettingsViewModel viewModel;
 
 	private static final String ARG_URI = "uri";
 	private Uri uri;
@@ -51,6 +54,9 @@ public class ConfirmAvatarDialogFragment extends DialogFragment {
 	public void onAttach(Context ctx) {
 		super.onAttach(ctx);
 		((BaseActivity) requireActivity()).getActivityComponent().inject(this);
+		ViewModelProvider provider =
+				new ViewModelProvider(requireActivity(), viewModelFactory);
+		viewModel = provider.get(SettingsViewModel.class);
 	}
 
 	@Override
@@ -60,32 +66,34 @@ public class ConfirmAvatarDialogFragment extends DialogFragment {
 		uri = Uri.parse(argUri);
 
 		FragmentActivity activity = requireActivity();
-
+		LayoutInflater inflater = LayoutInflater.from(activity);
-		ViewModelProvider provider =
-				new ViewModelProvider(activity, viewModelFactory);
-		settingsViewModel = provider.get(SettingsViewModel.class);
-
-		AlertDialog.Builder builder =
-				new AlertDialog.Builder(activity, R.style.BriarDialogTheme);
-
-		LayoutInflater inflater = LayoutInflater.from(getContext());
 		final View view =
 				inflater.inflate(R.layout.fragment_confirm_avatar_dialog, null);
-		builder.setView(view);
-
-		builder.setTitle(R.string.dialog_confirm_profile_picture_title);
-		builder.setNegativeButton(R.string.cancel, null);
-		builder.setPositiveButton(R.string.change,
-				(dialog, id) -> settingsViewModel.setAvatar(uri));
-
 		ImageView imageView = view.findViewById(R.id.image);
-		imageView.setImageURI(uri);
-
 		TextView textViewUserName = view.findViewById(R.id.username);
-		settingsViewModel.getOwnIdentityInfo().observe(activity,
-				us -> textViewUserName.setText(us.getLocalAuthor().getName()));
 
-		return builder.create();
+		GlideApp.with(imageView)
+				.load(uri)
+				.diskCacheStrategy(DiskCacheStrategy.NONE)
+				.error(R.drawable.ic_image_broken)
+				.into(imageView)
+				.waitForLayout();
+
+		// we can't use getViewLifecycleOwner() here
+		// as this fragment technically doesn't have a view
+		viewModel.getOwnIdentityInfo().observe(activity, us ->
+				textViewUserName.setText(us.getLocalAuthor().getName())
+		);
+
+		int theme = R.style.BriarDialogTheme;
+		return new AlertDialog.Builder(activity, theme)
+				.setView(view)
+				.setTitle(R.string.dialog_confirm_profile_picture_title)
+				.setNegativeButton(R.string.cancel, null)
+				.setPositiveButton(R.string.change, (d, id) ->
+						viewModel.setAvatar(uri)
+				)
+				.create();
 	}
 
 }

briar-android/src/main/java/org/briarproject/briar/android/settings/SettingsViewModel.java

@@ -79,7 +79,7 @@ class SettingsViewModel extends AndroidViewModel {
 		return ownIdentityInfo;
 	}
 
-	public LiveEvent<Boolean> getSetAvatarFailed() {
+	LiveEvent<Boolean> getSetAvatarFailed() {
 		return setAvatarFailed;
 	}
 

briar-android/src/main/java/org/briarproject/briar/android/util/RequestBluetoothDiscoverable.java

@@ -0,0 +1,31 @@
+package org.briarproject.briar.android.util;
+
+
+import android.content.Context;
+import android.content.Intent;
+
+import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
+
+import androidx.activity.result.contract.ActivityResultContract;
+import androidx.annotation.Nullable;
+
+import static android.app.Activity.RESULT_CANCELED;
+import static android.bluetooth.BluetoothAdapter.ACTION_REQUEST_DISCOVERABLE;
+import static android.bluetooth.BluetoothAdapter.EXTRA_DISCOVERABLE_DURATION;
+
+@NotNullByDefault
+public class RequestBluetoothDiscoverable
+		extends ActivityResultContract<Integer, Boolean> {
+
+	@Override
+	public Intent createIntent(Context context, Integer duration) {
+		Intent i = new Intent(ACTION_REQUEST_DISCOVERABLE);
+		i.putExtra(EXTRA_DISCOVERABLE_DURATION, duration);
+		return i;
+	}
+
+	@Override
+	public Boolean parseResult(int resultCode, @Nullable Intent intent) {
+		return resultCode != RESULT_CANCELED;
+	}
+}

briar-android/src/main/java/org/briarproject/briar/android/view/BriarRecyclerView.java

@@ -52,7 +52,8 @@ public class BriarRecyclerView extends FrameLayout {
 				R.styleable.BriarRecyclerView);
 		isScrollingToEnd = attributes
 				.getBoolean(R.styleable.BriarRecyclerView_scrollToEnd, true);
-		int drawableRes = attributes.getResourceId(R.styleable.BriarRecyclerView_emptyImage, -1);
+		int drawableRes = attributes
+				.getResourceId(R.styleable.BriarRecyclerView_emptyImage, -1);
 		if (drawableRes != -1) setEmptyImage(drawableRes);
 		String emtpyText =
 				attributes.getString(R.styleable.BriarRecyclerView_emptyText);
@@ -87,10 +88,30 @@ public class BriarRecyclerView extends FrameLayout {
 		}
 
 		emptyObserver = new RecyclerView.AdapterDataObserver() {
+
+			@Override
+			public void onChanged() {
+				super.onChanged();
+				showData();
+			}
+
+			@Override
+			public void onItemRangeChanged(int positionStart, int itemCount) {
+				super.onItemRangeChanged(positionStart, itemCount);
+				if (itemCount > 0) showData();
+			}
+
+			@Override
+			public void onItemRangeMoved(int fromPosition, int toPosition,
+					int itemCount) {
+				super.onItemRangeMoved(fromPosition, toPosition, itemCount);
+				if (itemCount > 0) showData();
+			}
+
 			@Override
 			public void onItemRangeInserted(int positionStart, int itemCount) {
 				super.onItemRangeInserted(positionStart, itemCount);
-				if (itemCount > 0) showData();
+				showData();
 			}
 
 			@Override

briar-android/src/main/java/org/briarproject/briar/android/viewmodel/DbViewModel.java

@@ -43,7 +43,7 @@ public abstract class DbViewModel extends AndroidViewModel {
 	private final Executor dbExecutor;
 	private final LifecycleManager lifecycleManager;
 	private final TransactionManager db;
-	private final AndroidExecutor androidExecutor;
+	protected final AndroidExecutor androidExecutor;
 
 	public DbViewModel(
 			@NonNull Application application,

briar-android/src/main/res/anim/fade_in.xml

@@ -1,7 +1,6 @@
 <?xml version="1.0" encoding="utf-8"?>
-<alpha
+<alpha xmlns:android="http://schemas.android.com/apk/res/android"
-	xmlns:android="http://schemas.android.com/apk/res/android"
+	android:duration="@integer/animationSpeed"
-	android:duration="@android:integer/config_longAnimTime"
 	android:fromAlpha="0.0"
 	android:interpolator="@android:interpolator/decelerate_quad"
-	android:toAlpha="1.0"/>
+	android:toAlpha="1.0" />

briar-android/src/main/res/anim/fade_out.xml

@@ -1,7 +1,6 @@
 <?xml version="1.0" encoding="utf-8"?>
-<alpha
+<alpha xmlns:android="http://schemas.android.com/apk/res/android"
-	xmlns:android="http://schemas.android.com/apk/res/android"
+	android:duration="@integer/animationSpeed"
-	android:duration="@android:integer/config_mediumAnimTime"
 	android:fromAlpha="1.0"
 	android:interpolator="@android:interpolator/accelerate_quad"
-	android:toAlpha="0.0"/>
+	android:toAlpha="0.0" />

briar-android/src/main/res/anim/screen_new_in.xml

@@ -1,12 +1,11 @@
 <?xml version="1.0" encoding="utf-8"?>
-<set
+<set xmlns:android="http://schemas.android.com/apk/res/android">
-	xmlns:android="http://schemas.android.com/apk/res/android">
 
 	<!-- slide in from right -->
 	<translate
-		android:duration="@android:integer/config_mediumAnimTime"
+		android:duration="@integer/animationSpeed"
 		android:fromXDelta="100%p"
 		android:interpolator="@android:interpolator/decelerate_quad"
-		android:toXDelta="0"/>
+		android:toXDelta="0" />
 
 </set>

briar-android/src/main/res/anim/screen_new_out.xml

@@ -1,12 +1,11 @@
 <?xml version="1.0" encoding="utf-8"?>
-<set
+<set xmlns:android="http://schemas.android.com/apk/res/android">
-	xmlns:android="http://schemas.android.com/apk/res/android">
 
 	<!-- slide out to right -->
 	<translate
-		android:duration="@android:integer/config_mediumAnimTime"
+		android:duration="@integer/animationSpeed"
 		android:fromXDelta="0"
 		android:interpolator="@android:interpolator/accelerate_quad"
-		android:toXDelta="100%p"/>
+		android:toXDelta="100%p" />
 
 </set>

briar-android/src/main/res/anim/screen_old_in.xml

@@ -1,7 +1,6 @@
 <?xml version="1.0" encoding="utf-8"?>
-<alpha
+<alpha xmlns:android="http://schemas.android.com/apk/res/android"
-	xmlns:android="http://schemas.android.com/apk/res/android"
+	android:duration="@integer/animationSpeed"
-	android:duration="@android:integer/config_mediumAnimTime"
 	android:fromAlpha="0.0"
 	android:interpolator="@android:interpolator/decelerate_quad"
-	android:toAlpha="1.0"/>
+	android:toAlpha="1.0" />

briar-android/src/main/res/anim/screen_old_out.xml

@@ -1,7 +1,6 @@
 <?xml version="1.0" encoding="utf-8"?>
-<alpha
+<alpha xmlns:android="http://schemas.android.com/apk/res/android"
-	xmlns:android="http://schemas.android.com/apk/res/android"
+	android:duration="@integer/animationSpeed"
-	android:duration="@android:integer/config_mediumAnimTime"
 	android:fromAlpha="1.0"
 	android:interpolator="@android:interpolator/accelerate_quad"
-	android:toAlpha="0.0"/>
+	android:toAlpha="0.0" />

briar-android/src/main/res/anim/step_next_in.xml

@@ -4,7 +4,7 @@
 
 	<!-- slide in from right -->
 	<translate
-		android:duration="@android:integer/config_mediumAnimTime"
+		android:duration="@integer/animationSpeed"
 		android:fromXDelta="100%p"
 		android:interpolator="@android:interpolator/decelerate_quad"
 		android:toXDelta="0"/>

briar-android/src/main/res/anim/step_next_out.xml

@@ -1,12 +1,11 @@
 <?xml version="1.0" encoding="utf-8"?>
-<set
+<set xmlns:android="http://schemas.android.com/apk/res/android">
-	xmlns:android="http://schemas.android.com/apk/res/android">
 
 	<!-- slide out to right -->
 	<translate
-		android:duration="@android:integer/config_mediumAnimTime"
+		android:duration="@integer/animationSpeed"
 		android:fromXDelta="0"
 		android:interpolator="@android:interpolator/accelerate_quad"
-		android:toXDelta="100%p"/>
+		android:toXDelta="100%p" />
 
 </set>

briar-android/src/main/res/anim/step_previous_in.xml

@@ -1,7 +1,6 @@
 <?xml version="1.0" encoding="utf-8"?>
-<alpha
+<alpha xmlns:android="http://schemas.android.com/apk/res/android"
-	xmlns:android="http://schemas.android.com/apk/res/android"
+	android:duration="@integer/animationSpeed"
-	android:duration="@android:integer/config_mediumAnimTime"
 	android:fromAlpha="0.0"
 	android:interpolator="@android:interpolator/decelerate_quad"
-	android:toAlpha="1.0"/>
+	android:toAlpha="1.0" />

briar-android/src/main/res/anim/step_previous_out.xml

@@ -1,7 +1,6 @@
 <?xml version="1.0" encoding="utf-8"?>
-<alpha
+<alpha xmlns:android="http://schemas.android.com/apk/res/android"
-	xmlns:android="http://schemas.android.com/apk/res/android"
+	android:duration="@integer/animationSpeed"
-	android:duration="@android:integer/config_mediumAnimTime"
 	android:fromAlpha="1.0"
 	android:interpolator="@android:interpolator/accelerate_quad"
-	android:toAlpha="0.0"/>
+	android:toAlpha="0.0" />

briar-android/src/main/res/layout/activity_fragment_container_toolbar.xml

@@ -4,11 +4,11 @@
 	android:layout_width="match_parent"
 	android:layout_height="match_parent"
 	android:orientation="vertical"
-	tools:context=".android.keyagreement.KeyAgreementActivity">
+	tools:context=".android.contact.add.nearby.AddNearbyContactActivity">
 
 	<include layout="@layout/toolbar" />
 
-	<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
+	<FrameLayout
 		android:id="@+id/fragmentContainer"
 		android:layout_width="match_parent"
 		android:layout_height="match_parent" />

briar-android/src/main/res/layout/activity_nav_drawer.xml

@@ -52,16 +52,17 @@
 				android:layout_height="0dp"
 				android:contentDescription="@string/close"
 				android:scaleType="center"
-				app:srcCompat="@drawable/ic_close"
 				app:layout_constraintBottom_toBottomOf="parent"
 				app:layout_constraintEnd_toEndOf="parent"
 				app:layout_constraintTop_toTopOf="parent"
+				app:srcCompat="@drawable/ic_close"
 				app:tint="@color/briar_text_tertiary_inverse" />
 
 		</androidx.constraintlayout.widget.ConstraintLayout>
 
-		<FrameLayout
+		<androidx.fragment.app.FragmentContainerView
 			android:id="@+id/fragmentContainer"
+			android:name="org.briarproject.briar.android.contact.ContactListFragment"
 			android:layout_width="0dp"
 			android:layout_height="0dp"
 			app:layout_constraintBottom_toBottomOf="parent"

briar-android/src/main/res/layout/fragment_keyagreement_qr.xml

@@ -5,7 +5,7 @@
 	android:layout_height="match_parent"
 	android:keepScreenOn="true">
 
-	<org.briarproject.briar.android.keyagreement.CameraView
+	<org.briarproject.briar.android.contact.add.nearby.CameraView
 		android:id="@+id/camera_view"
 		android:layout_width="match_parent"
 		android:layout_height="match_parent" />

briar-android/src/main/res/menu/navigation_drawer.xml

@@ -5,27 +5,28 @@
 	<group android:checkableBehavior="single">
 		<item
 			android:id="@+id/nav_btn_contacts"
+			android:checked="true"
 			android:icon="@drawable/ic_contacts"
-			android:title="@string/contact_list_button"/>
+			android:title="@string/contact_list_button" />
 		<item
 			android:id="@+id/nav_btn_groups"
 			android:icon="@drawable/ic_group"
-			android:title="@string/groups_button"/>
+			android:title="@string/groups_button" />
 		<item
 			android:id="@+id/nav_btn_forums"
 			android:icon="@drawable/ic_forums_black_24dp"
-			android:title="@string/forums_button"/>
+			android:title="@string/forums_button" />
 		<item
 			android:id="@+id/nav_btn_blogs"
 			android:icon="@drawable/blogs"
-			android:title="@string/blogs_button"/>
+			android:title="@string/blogs_button" />
 	</group>
 
 	<group android:checkableBehavior="single">
 		<item
 			android:id="@+id/nav_btn_settings"
 			android:icon="@drawable/ic_settings_black"
-			android:title="@string/settings_button"/>
+			android:title="@string/settings_button" />
 		<item
 			android:id="@+id/nav_btn_lock"
 			android:icon="@drawable/startup_lock"
@@ -35,7 +36,7 @@
 		<item
 			android:id="@+id/nav_btn_signout"
 			android:icon="@drawable/ic_signout"
-			android:title="@string/sign_out_button"/>
+			android:title="@string/sign_out_button" />
 	</group>
 
 </menu>

briar-android/src/main/res/values/attrs.xml

@@ -1,6 +1,8 @@
 <?xml version="1.0" encoding="utf-8"?>
 <resources>
 
+	<integer name="animationSpeed">@android:integer/config_mediumAnimTime</integer>
+
 	<declare-styleable name="BriarRecyclerView">
 		<attr name="scrollToEnd" format="boolean" />
 		<attr name="emptyImage" format="integer" />

briar-android/src/main/res/xml/backup_rules.xml

@@ -0,0 +1,18 @@
+<?xml version="1.0" encoding="utf-8"?>
+<full-backup-content>
+	<!-- docs: https://developer.android.com/guide/topics/data/autobackup#XMLSyntax -->
+	<exclude
+		domain="root"
+		path="." />
+	<!-- the previous entry should exclude things recursively, but we add more just to be sure -->
+	<exclude
+		domain="root"
+		path="app_db" />
+	<exclude
+		domain="root"
+		path="app_key" />
+	<!-- we don't use domain=file (getFilesDir()), but ApplicationInfo#dataDir -->
+	<exclude
+		domain="sharedpref"
+		path="." />
+</full-backup-content>

briar-android/witness.gradle

@@ -1,7 +1,7 @@
 dependencyVerification {
     verify = [
         'androidx.activity:activity-ktx:1.1.0:activity-ktx-1.1.0.aar:1996c36d3d2d62db5020b8ec634b5f854b1a698960c3552e1a00c69221baeabe',
-        'androidx.activity:activity:1.1.0:activity-1.1.0.aar:4f2b35916768032f7d0c20e250e28b29037ed4ce9ebf3da4fcd51bcb0c6067ef',
+        'androidx.activity:activity:1.2.0:activity-1.2.0.aar:ac27a810554e47b2122bce1f338934e77b173a5a9267eb35f134b6d34f931bae',
         'androidx.annotation:annotation-experimental:1.0.0:annotation-experimental-1.0.0.aar:b219d2b568e7e4ba534e09f8c2fd242343df6ccbdfbbe938846f5d740e6b0b11',
         'androidx.annotation:annotation:1.1.0:annotation-1.1.0.jar:d38d63edb30f1467818d50aaf05f8a692dea8b31392a049bfa991b159ad5b692',
         'androidx.appcompat:appcompat-resources:1.2.0:appcompat-resources-1.2.0.aar:c470297c03ff3de1c3d15dacf0be0cae63abc10b52f021dd07ae28daa3100fe5',
@@ -24,29 +24,28 @@ dependencyVerification {
         'androidx.exifinterface:exifinterface:1.3.1:exifinterface-1.3.1.aar:ef168daa6eb744c8395c22b49afa5235e6099868a0377175b6d5e3cdff8d7ffc',
         'androidx.fragment:fragment-ktx:1.2.5:fragment-ktx-1.2.5.aar:50f0f3b734f93829eeac7456b7cb13e5430741e555c535911a958ee4a8242bca',
         'androidx.fragment:fragment-testing:1.2.5:fragment-testing-1.2.5.aar:ef3cc3387115f9187665b283e313b13a2bb8826673380317057e2972351df09c',
-        'androidx.fragment:fragment:1.2.4:fragment-1.2.4.aar:1dc194942574302bf35dae7b81b82273505ec2d38f81d9258ad5c0448daddd82',
+        'androidx.fragment:fragment:1.3.0:fragment-1.3.0.aar:66db3ed2b11bb5e572a079b87cd3fae9bc5c33c373c71b25f1e3eac7607ab526',
-        'androidx.fragment:fragment:1.2.5:fragment-1.2.5.aar:d19e82d142def6c4e136da70bf92f194c0ecc61d14ab4e84567b2ced0920fa93',
         'androidx.interpolator:interpolator:1.0.0:interpolator-1.0.0.aar:33193135a64fe21fa2c35eec6688f1a76e512606c0fc83dc1b689e37add7732a',
         'androidx.legacy:legacy-support-core-utils:1.0.0:legacy-support-core-utils-1.0.0.aar:a7edcf01d5b52b3034073027bc4775b78a4764bb6202bb91d61c829add8dd1c7',
-        'androidx.lifecycle:lifecycle-common:2.2.0:lifecycle-common-2.2.0.jar:63898dabf7cfe5ec5d7ed8b8c2564c1427be876e1496ead95c2703cf59d3734b',
+        'androidx.lifecycle:lifecycle-common:2.3.0:lifecycle-common-2.3.0.jar:15848fb56db32f4c7cdc72b324003183d52a4884d6bf09be708ac7f587d139b5',
         'androidx.lifecycle:lifecycle-extensions:2.2.0:lifecycle-extensions-2.2.0.aar:648c8de1d10b025d524a2e46ac994fc3f6bf186826c09ec1a62d250bf1b877ae',
         'androidx.lifecycle:lifecycle-livedata-core-ktx:2.2.0:lifecycle-livedata-core-ktx-2.2.0.aar:5951f882e95b7e05ceb9adfca0fa2ebd511d63ea5a00da4eae6c6d0c1903da18',
-        'androidx.lifecycle:lifecycle-livedata-core:2.2.0:lifecycle-livedata-core-2.2.0.aar:556c1f3af90aa9d7d0d330565adbf6da71b2429148bac91e07c485f4f9abf614',
+        'androidx.lifecycle:lifecycle-livedata-core:2.3.0:lifecycle-livedata-core-2.3.0.aar:89f480888f2bb8eb62d9b7b1eb34be69b59ec84b24a1b0bdbeb49973478c6da3',
         'androidx.lifecycle:lifecycle-livedata:2.2.0:lifecycle-livedata-2.2.0.aar:d83af94860aa9f64cbdc51f40796a7cf55b116f0e6efd752e845c0104c8b16f6',
         'androidx.lifecycle:lifecycle-process:2.2.0:lifecycle-process-2.2.0.aar:3a977e7778fc8418742d388409daaba7ea8fea8823d21ffb96e4c4236f715070',
         'androidx.lifecycle:lifecycle-runtime-ktx:2.2.0:lifecycle-runtime-ktx-2.2.0.aar:c29fc87694e6ce116b61207221e53ed285862a6628055790b0bcf9ce45d8cc68',
-        'androidx.lifecycle:lifecycle-runtime:2.2.0:lifecycle-runtime-2.2.0.aar:2f866c07a1f33a8c9bb69a9545d4f20b4f0628cd0a155432386d7cb081e1e0bc',
+        'androidx.lifecycle:lifecycle-runtime:2.3.0:lifecycle-runtime-2.3.0.aar:94f528fd5fb123f75b6e65d07a6ef5cd6c0e69ac604d106aaa12705282456234',
         'androidx.lifecycle:lifecycle-service:2.2.0:lifecycle-service-2.2.0.aar:ca2801ffc069555afed8eddd2292130f436956452bc8bbad30fb56f8e4e382a0',
         'androidx.lifecycle:lifecycle-viewmodel-ktx:2.2.0:lifecycle-viewmodel-ktx-2.2.0.aar:f791001f2211947e56ad3d96d12c9ae93fc5589b88f08603f69a2265c9a7d702',
-        'androidx.lifecycle:lifecycle-viewmodel-savedstate:2.2.0:lifecycle-viewmodel-savedstate-2.2.0.aar:3ce866fb822b20fe2f188f974992869a0a6233fe40acbefcff090d6def5e7f33',
+        'androidx.lifecycle:lifecycle-viewmodel-savedstate:2.3.0:lifecycle-viewmodel-savedstate-2.3.0.aar:49f9532b5104cc1ee64900ed4f696d031d807fba726e0d5d6a52459e8fba4a1d',
-        'androidx.lifecycle:lifecycle-viewmodel:2.2.0:lifecycle-viewmodel-2.2.0.aar:967efab24d6c49dd414a8c0ac4a1cd09b018f0b8bb43b739ad360c4158ebde27',
+        'androidx.lifecycle:lifecycle-viewmodel:2.3.0:lifecycle-viewmodel-2.3.0.aar:cea8f26fa232037922b69af9cd1bde2df1211acc8b75253e425b7150a5fca59d',
         'androidx.loader:loader:1.0.0:loader-1.0.0.aar:11f735cb3b55c458d470bed9e25254375b518b4b1bad6926783a7026db0f5025',
         'androidx.localbroadcastmanager:localbroadcastmanager:1.0.0:localbroadcastmanager-1.0.0.aar:e71c328ceef5c4a7d76f2d86df1b65d65fe2acf868b1a4efd84a3f34336186d8',
         'androidx.preference:preference:1.1.1:preference-1.1.1.aar:317dcbc38242aea2f6262c06d51b8a22827e98959967edd40f82600a15cb4bff',
         'androidx.print:print:1.0.0:print-1.0.0.aar:1d5c7f3135a1bba661fc373fd72e11eb0a4adbb3396787826dd8e4190d5d9edd',
         'androidx.recyclerview:recyclerview-selection:1.1.0-rc03:recyclerview-selection-1.1.0-rc03.aar:a548a0771c2c8ca8cf98f1f755b0eef4fac73d1697e6eeb1a6383f557e0eba13',
         'androidx.recyclerview:recyclerview:1.1.0:recyclerview-1.1.0.aar:f0d2b5a67d0a91ee1b1c73ef2b636a81f3563925ddd15a1d4e1c41ec28de7a4f',
-        'androidx.savedstate:savedstate:1.0.0:savedstate-1.0.0.aar:2510a5619c37579c9ce1a04574faaf323cd0ffe2fc4e20fa8f8f01e5bb402e83',
+        'androidx.savedstate:savedstate:1.1.0:savedstate-1.1.0.aar:d60bbe44c2c08083a17c5dc678a6d6b4d0a2d664858016ab5c049cbea90a63b7',
         'androidx.test.espresso:espresso-contrib:3.3.0:espresso-contrib-3.3.0.aar:f400cabdc181356acf6b210e4509dcb9649d9e2b6b6e218c60fcfc15e8a756d1',
         'androidx.test.espresso:espresso-core:3.3.0:espresso-core-3.3.0.aar:23ebf6014645e0c60aec7d1ed924d4d4c848ae8c3673b7d8d06b2ec6a56cafee',
         'androidx.test.espresso:espresso-idling-resource:3.3.0:espresso-idling-resource-3.3.0.aar:29519b112731f289cc6e2f9b2eccc5ea72c754b04272bb93370f45d7e170a7c6',
@@ -57,6 +56,7 @@ dependencyVerification {
         'androidx.test:monitor:1.3.0:monitor-1.3.0.aar:f73a31306a783e63150c60c49e140dc38da39a1b7947690f4b73387b5ebad77e',
         'androidx.test:rules:1.3.0:rules-1.3.0.aar:c1753946c498b0d5d7cf341cfed661f66915c4c9deb4ed10462a08ae33b2429a',
         'androidx.test:runner:1.3.0:runner-1.3.0.aar:61d13f5a9fcbbd73ba18fa84e1d6a0111c6e1c665a89b418126966e61fffd93b',
+        'androidx.tracing:tracing:1.0.0:tracing-1.0.0.aar:07b8b6139665b884a162eccf97891ca50f7f56831233bf25168ae04f7b568612',
         'androidx.transition:transition:1.2.0:transition-1.2.0.aar:a1e059b3bc0b43a58dec0efecdcaa89c82d2bca552ea5bacf6656c46e853157e',
         'androidx.vectordrawable:vectordrawable-animated:1.1.0:vectordrawable-animated-1.1.0.aar:76da2c502371d9c38054df5e2b248d00da87809ed058f3363eae87ce5e2403f8',
         'androidx.vectordrawable:vectordrawable:1.1.0:vectordrawable-1.1.0.aar:46fd633ac01b49b7fcabc263bf098c5a8b9e9a69774d234edcca04fb02df8e26',

briar-api/src/main/java/org/briarproject/briar/api/attachment/MediaConstants.java

@@ -11,7 +11,7 @@ public interface MediaConstants {
 	/**
 	 * The maximum length of an attachment's content type in UTF-8 bytes.
 	 */
-	int MAX_CONTENT_TYPE_BYTES = 50;
+	int MAX_CONTENT_TYPE_BYTES = 80;
 
 	/**
 	 * The maximum allowed size of image attachments.

briar-api/src/main/java/org/briarproject/briar/api/messaging/MessagingConstants.java

@@ -7,7 +7,17 @@ public interface MessagingConstants {
 	/**
 	 * The maximum length of a private message's text in UTF-8 bytes.
 	 */
-	int MAX_PRIVATE_MESSAGE_TEXT_LENGTH = MAX_MESSAGE_BODY_LENGTH - 1024;
+	int MAX_PRIVATE_MESSAGE_TEXT_LENGTH = MAX_MESSAGE_BODY_LENGTH - 2048;
+
+	/**
+	 * The maximum length of an incoming private message's text in UTF-8 bytes.
+	 * This is higher than MAX_PRIVATE_MESSAGE_TEXT_LENGTH for compatibility
+	 * with older peers.
+	 * <p>
+	 * TODO: Remove after a reasonable migration period (added 2021-03-12).
+	 */
+	int MAX_PRIVATE_MESSAGE_INCOMING_TEXT_LENGTH =
+			MAX_MESSAGE_BODY_LENGTH - 1024;
 
 	/**
 	 * The maximum number of attachments per private message.

briar-core/src/main/java/org/briarproject/briar/messaging/PrivateMessageValidator.java

@@ -32,7 +32,7 @@ import static org.briarproject.briar.api.attachment.MediaConstants.MAX_CONTENT_T
 import static org.briarproject.briar.api.attachment.MediaConstants.MSG_KEY_CONTENT_TYPE;
 import static org.briarproject.briar.api.attachment.MediaConstants.MSG_KEY_DESCRIPTOR_LENGTH;
 import static org.briarproject.briar.api.messaging.MessagingConstants.MAX_ATTACHMENTS_PER_MESSAGE;
-import static org.briarproject.briar.api.messaging.MessagingConstants.MAX_PRIVATE_MESSAGE_TEXT_LENGTH;
+import static org.briarproject.briar.api.messaging.MessagingConstants.MAX_PRIVATE_MESSAGE_INCOMING_TEXT_LENGTH;
 import static org.briarproject.briar.client.MessageTrackerConstants.MSG_KEY_READ;
 import static org.briarproject.briar.messaging.MessageTypes.ATTACHMENT;
 import static org.briarproject.briar.messaging.MessageTypes.PRIVATE_MESSAGE;
@@ -103,7 +103,7 @@ class PrivateMessageValidator implements MessageValidator {
 		// Private message text
 		checkSize(body, 1);
 		String text = body.getString(0);
-		checkLength(text, 0, MAX_PRIVATE_MESSAGE_TEXT_LENGTH);
+		checkLength(text, 0, MAX_PRIVATE_MESSAGE_INCOMING_TEXT_LENGTH);
 		// Return the metadata
 		BdfDictionary meta = new BdfDictionary();
 		meta.put(MSG_KEY_TIMESTAMP, m.getTimestamp());
@@ -117,7 +117,7 @@ class PrivateMessageValidator implements MessageValidator {
 		// Message type, optional private message text, attachment headers
 		checkSize(body, 3);
 		String text = body.getOptionalString(1);
-		checkLength(text, 0, MAX_PRIVATE_MESSAGE_TEXT_LENGTH);
+		checkLength(text, 0, MAX_PRIVATE_MESSAGE_INCOMING_TEXT_LENGTH);
 		BdfList headers = body.getList(2);
 		if (text == null) checkSize(headers, 1, MAX_ATTACHMENTS_PER_MESSAGE);
 		else checkSize(headers, 0, MAX_ATTACHMENTS_PER_MESSAGE);

briar-core/src/test/java/org/briarproject/briar/messaging/MessageSizeIntegrationTest.java

@@ -1,10 +1,14 @@
 package org.briarproject.briar.messaging;
 
 import org.briarproject.bramble.api.UniqueId;
+import org.briarproject.bramble.api.client.ClientHelper;
 import org.briarproject.bramble.api.crypto.CryptoComponent;
+import org.briarproject.bramble.api.data.BdfList;
 import org.briarproject.bramble.api.identity.AuthorFactory;
 import org.briarproject.bramble.api.identity.LocalAuthor;
 import org.briarproject.bramble.api.sync.GroupId;
+import org.briarproject.bramble.api.sync.Message;
+import org.briarproject.bramble.api.sync.MessageFactory;
 import org.briarproject.bramble.api.sync.MessageId;
 import org.briarproject.briar.api.attachment.AttachmentHeader;
 import org.briarproject.briar.api.forum.ForumPost;
@@ -14,6 +18,8 @@ import org.briarproject.briar.api.messaging.PrivateMessageFactory;
 import org.briarproject.briar.test.BriarTestCase;
 import org.junit.Test;
 
+import java.io.ByteArrayInputStream;
+import java.io.ByteArrayOutputStream;
 import java.util.ArrayList;
 import java.util.List;
 
@@ -22,12 +28,16 @@ import javax.inject.Inject;
 import static org.briarproject.bramble.api.identity.AuthorConstants.MAX_AUTHOR_NAME_LENGTH;
 import static org.briarproject.bramble.api.identity.AuthorConstants.MAX_PUBLIC_KEY_LENGTH;
 import static org.briarproject.bramble.api.record.Record.MAX_RECORD_PAYLOAD_BYTES;
+import static org.briarproject.bramble.test.TestUtils.getRandomBytes;
 import static org.briarproject.bramble.test.TestUtils.getRandomId;
+import static org.briarproject.bramble.util.IoUtils.copyAndClose;
 import static org.briarproject.bramble.util.StringUtils.getRandomString;
 import static org.briarproject.briar.api.attachment.MediaConstants.MAX_CONTENT_TYPE_BYTES;
+import static org.briarproject.briar.api.attachment.MediaConstants.MAX_IMAGE_SIZE;
 import static org.briarproject.briar.api.forum.ForumConstants.MAX_FORUM_POST_TEXT_LENGTH;
 import static org.briarproject.briar.api.messaging.MessagingConstants.MAX_ATTACHMENTS_PER_MESSAGE;
 import static org.briarproject.briar.api.messaging.MessagingConstants.MAX_PRIVATE_MESSAGE_TEXT_LENGTH;
+import static org.briarproject.briar.messaging.MessageTypes.ATTACHMENT;
 import static org.junit.Assert.assertTrue;
 
 public class MessageSizeIntegrationTest extends BriarTestCase {
@@ -40,6 +50,10 @@ public class MessageSizeIntegrationTest extends BriarTestCase {
 	PrivateMessageFactory privateMessageFactory;
 	@Inject
 	ForumPostFactory forumPostFactory;
+	@Inject
+	ClientHelper clientHelper;
+	@Inject
+	MessageFactory messageFactory;
 
 	public MessageSizeIntegrationTest() {
 		MessageSizeIntegrationTestComponent component =
@@ -87,6 +101,32 @@ public class MessageSizeIntegrationTest extends BriarTestCase {
 		assertTrue(length <= MAX_RECORD_PAYLOAD_BYTES);
 	}
 
+	@Test
+	public void testAttachmentFitsIntoRecord() throws Exception {
+		// Create a maximum-length attachment
+		String contentType = getRandomString(MAX_CONTENT_TYPE_BYTES);
+		byte[] data = getRandomBytes(MAX_IMAGE_SIZE);
+
+		ByteArrayInputStream dataIn = new ByteArrayInputStream(data);
+		ByteArrayOutputStream bodyOut = new ByteArrayOutputStream();
+		byte[] descriptor =
+				clientHelper.toByteArray(BdfList.of(ATTACHMENT, contentType));
+		bodyOut.write(descriptor);
+		copyAndClose(dataIn, bodyOut);
+		byte[] body = bodyOut.toByteArray();
+
+		GroupId groupId = new GroupId(getRandomId());
+		long timestamp = Long.MAX_VALUE;
+		Message message =
+				messageFactory.createMessage(groupId, timestamp, body);
+
+		// Check the size of the serialised message
+		int length = message.getRawLength();
+		assertTrue(length > UniqueId.LENGTH + 8
+				+ 1 + MAX_CONTENT_TYPE_BYTES + MAX_IMAGE_SIZE);
+		assertTrue(length <= MAX_RECORD_PAYLOAD_BYTES);
+	}
+
 	@Test
 	public void testForumPostFitsIntoRecord() throws Exception {
 		// Create a maximum-length author

briar-core/src/test/java/org/briarproject/briar/messaging/PrivateMessageValidatorTest.java

@@ -31,7 +31,7 @@ import static org.briarproject.briar.api.attachment.MediaConstants.MAX_CONTENT_T
 import static org.briarproject.briar.api.attachment.MediaConstants.MSG_KEY_CONTENT_TYPE;
 import static org.briarproject.briar.api.attachment.MediaConstants.MSG_KEY_DESCRIPTOR_LENGTH;
 import static org.briarproject.briar.api.messaging.MessagingConstants.MAX_ATTACHMENTS_PER_MESSAGE;
-import static org.briarproject.briar.api.messaging.MessagingConstants.MAX_PRIVATE_MESSAGE_TEXT_LENGTH;
+import static org.briarproject.briar.api.messaging.MessagingConstants.MAX_PRIVATE_MESSAGE_INCOMING_TEXT_LENGTH;
 import static org.briarproject.briar.client.MessageTrackerConstants.MSG_KEY_READ;
 import static org.briarproject.briar.messaging.MessageTypes.ATTACHMENT;
 import static org.briarproject.briar.messaging.MessageTypes.PRIVATE_MESSAGE;
@@ -55,7 +55,7 @@ public class PrivateMessageValidatorTest extends BrambleMockTestCase {
 	private final Message message = getMessage(group.getId());
 	private final long now = message.getTimestamp() + 1000;
 	private final String text =
-			getRandomString(MAX_PRIVATE_MESSAGE_TEXT_LENGTH);
+			getRandomString(MAX_PRIVATE_MESSAGE_INCOMING_TEXT_LENGTH);
 	private final BdfList attachmentHeader = getAttachmentHeader();
 	private final MessageId attachmentId = new MessageId(getRandomId());
 	private final String contentType = getRandomString(MAX_CONTENT_TYPE_BYTES);
@@ -132,7 +132,7 @@ public class PrivateMessageValidatorTest extends BrambleMockTestCase {
 	@Test(expected = InvalidMessageException.class)
 	public void testRejectsTooLongTextForLegacyMessage() throws Exception {
 		String invalidText =
-				getRandomString(MAX_PRIVATE_MESSAGE_TEXT_LENGTH + 1);
+				getRandomString(MAX_PRIVATE_MESSAGE_INCOMING_TEXT_LENGTH + 1);
 
 		testRejectsLegacyMessage(BdfList.of(invalidText));
 	}
@@ -190,7 +190,7 @@ public class PrivateMessageValidatorTest extends BrambleMockTestCase {
 	@Test(expected = InvalidMessageException.class)
 	public void testRejectsTooLongTextForPrivateMessage() throws Exception {
 		String invalidText =
-				getRandomString(MAX_PRIVATE_MESSAGE_TEXT_LENGTH + 1);
+				getRandomString(MAX_PRIVATE_MESSAGE_INCOMING_TEXT_LENGTH + 1);
 
 		testRejectsPrivateMessage(
 				BdfList.of(PRIVATE_MESSAGE, invalidText, new BdfList()));

briar-headless/README.md

@@ -11,9 +11,11 @@ The REST API peer comes as a `jar` file
 and needs a Java Runtime Environment (JRE) that supports at least Java 8.
 It currently works only on GNU/Linux operating systems.
 
-To build the `jar` file, you can do this:
+To build the `jar` file, you need to specify the combination of architecture and platform:
 
-    $ ./gradlew --configure-on-demand briar-headless:jar
+    $ ./gradlew --configure-on-demand briar-headless:x86LinuxJar
+    $ ./gradlew --configure-on-demand briar-headless:aarch64LinuxJar
+    $ ./gradlew --configure-on-demand briar-headless:armhfLinuxJar
 
 You can start the peer (and its API server) like this:
 

briar-headless/build.gradle

@@ -44,18 +44,32 @@ dependencies {
 	kaptTest "com.google.dagger:dagger-compiler:$daggerVersion"
 }
 
-jar {
+void jarFactory(Jar jarTask, jarArchitecture) {
-	manifest {
+	jarTask.doFirst {
+		println 'Building ' + jarArchitecture + ' version has started'
+	}
+	jarTask.manifest {
 		attributes(
 				'Main-Class': 'org.briarproject.briar.headless.MainKt'
 		)
 	}
-	from {
+	jarTask.setArchiveClassifier(jarArchitecture)
+	jarTask.from {
 		configurations.runtimeClasspath.collect { it.isDirectory() ? it : zipTree(it) }
 	}
-	doLast() {
+			{
+				String[] architectures = ["linux-aarch64", "linux-armhf", "linux-x86_64"]
+				for (String arch : architectures) {
+					if (arch != jarArchitecture) {
+						exclude "obfs4proxy_" + arch + ".zip"
+						exclude "tor_" + arch + ".zip"
+					}
+				}
+			}
+	jarTask.with jar
+	jarTask.doLast {
 		// Rename the original jar
-		File jar = project.jar.archivePath
+		File jar = jarTask.archivePath
 		String srcPath = jar.toString().replaceFirst('\\.jar$', '.unsorted.jar')
 		File srcFile = new File(srcPath)
 		jar.renameTo(srcFile)
@@ -80,9 +94,22 @@ jar {
 		}
 		destStream.close()
 		srcJarFile.close()
+		println 'Building ' + jarArchitecture + ' version has finished'
 	}
 }
 
+task aarch64LinuxJar(type: Jar) {
+	jarFactory(it, 'linux-aarch64')
+}
+
+task armhfLinuxJar(type: Jar) {
+	jarFactory(it, 'linux-armhf')
+}
+
+task x86LinuxJar(type: Jar) {
+	jarFactory(it, 'linux-x86_64')
+}
+
 // At the moment for non-Android projects we need to explicitly mark the code generated by kapt
 // as 'generated source code' for correct highlighting and resolve in IDE.
 idea {