Fix tests.

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

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

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

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

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

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

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

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

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

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

bramble-api/src/main/java/org/briarproject/bramble/api/io/BlockSink.java

@@ -0,0 +1,20 @@
+package org.briarproject.bramble.api.io;
+
+import org.briarproject.bramble.api.db.DbException;
+import org.briarproject.bramble.api.sync.tree.TreeHash;
+
+import java.util.List;
+
+public interface BlockSink {
+
+	/**
+	 * Stores a block of the message with the given temporary ID.
+	 */
+	void putBlock(HashingId h, int blockNumber, byte[] data) throws DbException;
+
+	/**
+	 * Sets the hash tree path of a previously stored block.
+	 */
+	void setPath(HashingId h, int blockNumber, List<TreeHash> path)
+			throws DbException;
+}

bramble-api/src/main/java/org/briarproject/bramble/api/io/HashingId.java

@@ -0,0 +1,27 @@
+package org.briarproject.bramble.api.io;
+
+import org.briarproject.bramble.api.UniqueId;
+import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
+import org.briarproject.bramble.api.sync.Message;
+import org.briarproject.bramble.api.sync.MessageId;
+
+import javax.annotation.concurrent.ThreadSafe;
+
+/**
+ * Type-safe wrapper for a byte array that uniquely identifies a
+ * {@link Message} while it's being hashed and the {@link MessageId} is not
+ * yet known.
+ */
+@ThreadSafe
+@NotNullByDefault
+public class HashingId extends UniqueId {
+
+	public HashingId(byte[] id) {
+		super(id);
+	}
+
+	@Override
+	public boolean equals(Object o) {
+		return o instanceof HashingId && super.equals(o);
+	}
+}

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

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

bramble-api/src/main/java/org/briarproject/bramble/api/sync/MessageFactory.java

@@ -1,6 +1,7 @@
 package org.briarproject.bramble.api.sync;
 
 import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
+import org.briarproject.bramble.api.sync.tree.TreeHash;
 
 @NotNullByDefault
 public interface MessageFactory {
@@ -10,4 +11,6 @@ public interface MessageFactory {
 	Message createMessage(byte[] raw);
 
 	byte[] getRawMessage(Message m);
+
+	MessageId getMessageId(GroupId g, long timestamp, TreeHash rootHash);
 }

bramble-api/src/main/java/org/briarproject/bramble/api/sync/MessageId.java

@@ -24,6 +24,12 @@ public class MessageId extends UniqueId {
 	public static final String BLOCK_LABEL =
 			"org.briarproject.bramble/MESSAGE_BLOCK";
 
+	/**
+	 * Label for hashing two tree hashes to produce a parent.
+	 */
+	public static final String TREE_LABEL =
+			"org.briarproject.bramble/MESSAGE_TREE";
+
 	public MessageId(byte[] id) {
 		super(id);
 	}

bramble-api/src/main/java/org/briarproject/bramble/api/sync/SyncConstants.java

@@ -35,4 +35,9 @@ public interface SyncConstants {
 	 * The maximum number of message IDs in an ack, offer or request record.
 	 */
 	int MAX_MESSAGE_IDS = MAX_RECORD_PAYLOAD_BYTES / UniqueId.LENGTH;
+
+	/**
+	 * The maximum length of a message block in bytes.
+	 */
+	int MAX_BLOCK_LENGTH = 32 * 2014; // 32 KiB
 }

bramble-api/src/main/java/org/briarproject/bramble/api/sync/tree/LeafNode.java

@@ -0,0 +1,21 @@
+package org.briarproject.bramble.api.sync.tree;
+
+import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
+
+@NotNullByDefault
+public class LeafNode extends TreeNode {
+
+	public LeafNode(TreeHash hash, int blockNumber) {
+		super(hash, 0, blockNumber, blockNumber);
+	}
+
+	@Override
+	public TreeNode getLeftChild() {
+		throw new UnsupportedOperationException();
+	}
+
+	@Override
+	public TreeNode getRightChild() {
+		throw new UnsupportedOperationException();
+	}
+}

bramble-api/src/main/java/org/briarproject/bramble/api/sync/tree/ParentNode.java

@@ -0,0 +1,26 @@
+package org.briarproject.bramble.api.sync.tree;
+
+import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
+
+@NotNullByDefault
+public class ParentNode extends TreeNode {
+
+	private final TreeNode left, right;
+
+	public ParentNode(TreeHash hash, TreeNode left, TreeNode right) {
+		super(hash, Math.max(left.getHeight(), right.getHeight()) + 1,
+				left.getFirstBlockNumber(), right.getLastBlockNumber());
+		this.left = left;
+		this.right = right;
+	}
+
+	@Override
+	public TreeNode getLeftChild() {
+		return left;
+	}
+
+	@Override
+	public TreeNode getRightChild() {
+		return right;
+	}
+}

bramble-api/src/main/java/org/briarproject/bramble/api/sync/tree/StreamHasher.java

@@ -0,0 +1,21 @@
+package org.briarproject.bramble.api.sync.tree;
+
+import org.briarproject.bramble.api.db.DbException;
+import org.briarproject.bramble.api.io.BlockSink;
+import org.briarproject.bramble.api.io.HashingId;
+import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
+
+import java.io.IOException;
+import java.io.InputStream;
+
+@NotNullByDefault
+public interface StreamHasher {
+
+	/**
+	 * Reads the given input stream, divides the data into blocks, stores
+	 * the blocks and the resulting hash tree using the given block sink and
+	 * temporary ID, and returns the hash tree.
+	 */
+	TreeNode hash(InputStream in, BlockSink sink, HashingId h)
+			throws IOException, DbException;
+}

bramble-api/src/main/java/org/briarproject/bramble/api/sync/tree/TreeHash.java

@@ -0,0 +1,24 @@
+package org.briarproject.bramble.api.sync.tree;
+
+import org.briarproject.bramble.api.UniqueId;
+import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
+
+import javax.annotation.concurrent.ThreadSafe;
+
+/**
+ * Type-safe wrapper for a byte array that uniquely identifies a sequence of
+ * one or more message blocks.
+ */
+@ThreadSafe
+@NotNullByDefault
+public class TreeHash extends UniqueId {
+
+	public TreeHash(byte[] id) {
+		super(id);
+	}
+
+	@Override
+	public boolean equals(Object o) {
+		return o instanceof TreeHash && super.equals(o);
+	}
+}

bramble-api/src/main/java/org/briarproject/bramble/api/sync/tree/TreeHasher.java

@@ -0,0 +1,11 @@
+package org.briarproject.bramble.api.sync.tree;
+
+import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
+
+@NotNullByDefault
+public interface TreeHasher {
+
+	LeafNode hashBlock(int blockNumber, byte[] data);
+
+	ParentNode mergeTrees(TreeNode left, TreeNode right);
+}

bramble-api/src/main/java/org/briarproject/bramble/api/sync/tree/TreeNode.java

@@ -0,0 +1,38 @@
+package org.briarproject.bramble.api.sync.tree;
+
+import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
+
+@NotNullByDefault
+public abstract class TreeNode {
+
+	private final TreeHash hash;
+	private final int height, firstBlockNumber, lastBlockNumber;
+
+	TreeNode(TreeHash hash, int height, int firstBlockNumber,
+			int lastBlockNumber) {
+		this.hash = hash;
+		this.height = height;
+		this.firstBlockNumber = firstBlockNumber;
+		this.lastBlockNumber = lastBlockNumber;
+	}
+
+	public TreeHash getHash() {
+		return hash;
+	}
+
+	public int getHeight() {
+		return height;
+	}
+
+	public int getFirstBlockNumber() {
+		return firstBlockNumber;
+	}
+
+	public int getLastBlockNumber() {
+		return lastBlockNumber;
+	}
+
+	public abstract TreeNode getLeftChild();
+
+	public abstract TreeNode getRightChild();
+}

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

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

bramble-core/src/main/java/org/briarproject/bramble/PriorityExecutor.java

@@ -1,67 +0,0 @@
-package org.briarproject.bramble;
-
-import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
-
-import java.util.LinkedList;
-import java.util.Queue;
-import java.util.concurrent.Executor;
-
-import javax.annotation.concurrent.GuardedBy;
-
-@NotNullByDefault
-public class PriorityExecutor {
-
-	private final Object lock = new Object();
-	private final Executor delegate, high, low;
-	@GuardedBy("lock")
-	private final Queue<Runnable> highQueue = new LinkedList<>();
-	@GuardedBy("lock")
-	private final Queue<Runnable> lowQueue = new LinkedList<>();
-
-	@GuardedBy("lock")
-	private boolean isTaskRunning = false;
-
-	public PriorityExecutor(Executor delegate) {
-		this.delegate = delegate;
-		high = r -> submit(r, true);
-		low = r -> submit(r, false);
-	}
-
-	public Executor getHighPriorityExecutor() {
-		return high;
-	}
-
-	public Executor getLowPriorityExecutor() {
-		return low;
-	}
-
-	private void submit(Runnable r, boolean isHighPriority) {
-		Runnable wrapped = () -> {
-			try {
-				r.run();
-			} finally {
-				scheduleNext();
-			}
-		};
-		synchronized (lock) {
-			if (!isTaskRunning && highQueue.isEmpty() &&
-					(isHighPriority || lowQueue.isEmpty())) {
-				isTaskRunning = true;
-				delegate.execute(wrapped);
-			} else if (isHighPriority) {
-				highQueue.add(wrapped);
-			} else {
-				lowQueue.add(wrapped);
-			}
-		}
-	}
-
-	private void scheduleNext() {
-		synchronized (lock) {
-			Runnable next = highQueue.poll();
-			if (next == null) next = lowQueue.poll();
-			if (next == null) isTaskRunning = false;
-			else delegate.execute(next);
-		}
-	}
-}

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

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

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

@@ -69,7 +69,6 @@ import static org.briarproject.bramble.api.plugin.TorConstants.PREF_TOR_NETWORK;
 import static org.briarproject.bramble.api.plugin.TorConstants.PREF_TOR_NETWORK_AUTOMATIC;
 import static org.briarproject.bramble.api.plugin.TorConstants.PREF_TOR_NETWORK_NEVER;
 import static org.briarproject.bramble.api.plugin.TorConstants.PREF_TOR_NETWORK_WITH_BRIDGES;
-import static org.briarproject.bramble.api.plugin.TorConstants.PREF_TOR_ONLY_WHEN_CHARGING;
 import static org.briarproject.bramble.api.plugin.TorConstants.PREF_TOR_PORT;
 import static org.briarproject.bramble.api.plugin.TorConstants.PROP_ONION_V2;
 import static org.briarproject.bramble.api.plugin.TorConstants.PROP_ONION_V3;
@@ -649,10 +648,8 @@ abstract class TorPlugin implements DuplexPlugin, EventHandler, EventListener {
 			if (s.getNamespace().equals(ID.getString())) {
 				LOG.info("Tor settings updated");
 				settings = s.getSettings();
-				// Works around a bug introduced in Tor 0.3.4.8.
-				// https://trac.torproject.org/projects/tor/ticket/28027
-				// Could be replaced with callback.transportDisabled()
-				// when fixed.
+				// Works around a bug introduced in Tor 0.3.4.8. Could be
+				// replaced with callback.transportDisabled() when fixed.
 				disableNetwork();
 				updateConnectionStatus(networkManager.getNetworkStatus(),
 						batteryManager.isCharging());
@@ -688,8 +685,6 @@ abstract class TorPlugin implements DuplexPlugin, EventHandler, EventListener {
 			int network = settings.getInt(PREF_TOR_NETWORK,
 					PREF_TOR_NETWORK_AUTOMATIC);
 			boolean useMobile = settings.getBoolean(PREF_TOR_MOBILE, true);
-			boolean onlyWhenCharging =
-					settings.getBoolean(PREF_TOR_ONLY_WHEN_CHARGING, false);
 			boolean bridgesWork = circumventionProvider.doBridgesWork(country);
 			boolean automatic = network == PREF_TOR_NETWORK_AUTOMATIC;
 
@@ -704,12 +699,9 @@ abstract class TorPlugin implements DuplexPlugin, EventHandler, EventListener {
 				if (!online) {
 					LOG.info("Disabling network, device is offline");
 					enableNetwork(false);
-				} else if (!charging && onlyWhenCharging) {
-					LOG.info("Disabling network, device is on battery");
-					enableNetwork(false);
 				} else if (network == PREF_TOR_NETWORK_NEVER ||
 						(!useMobile && !wifi)) {
-					LOG.info("Disabling network, device is using mobile data");
+					LOG.info("Disabling network due to setting");
 					enableNetwork(false);
 				} else if (automatic && blocked && !bridgesWork) {
 					LOG.info("Disabling network, country is blocked");

bramble-core/src/main/java/org/briarproject/bramble/sync/MessageFactoryImpl.java

@@ -7,6 +7,7 @@ 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.bramble.api.sync.tree.TreeHash;
 import org.briarproject.bramble.util.ByteUtils;
 
 import javax.annotation.concurrent.Immutable;
@@ -39,13 +40,19 @@ class MessageFactoryImpl implements MessageFactory {
 		if (body.length == 0) throw new IllegalArgumentException();
 		if (body.length > MAX_MESSAGE_BODY_LENGTH)
 			throw new IllegalArgumentException();
-		MessageId id = getMessageId(g, timestamp, body);
+		MessageId id = getMessageIdFromBody(g, timestamp, body);
 		return new Message(id, g, timestamp, body);
 	}
 
-	private MessageId getMessageId(GroupId g, long timestamp, byte[] body) {
+	private MessageId getMessageIdFromBody(GroupId g, long timestamp,
+			byte[] body) {
 		// There's only one block, so the root hash is the hash of the block
 		byte[] rootHash = crypto.hash(BLOCK_LABEL, FORMAT_VERSION_BYTES, body);
+		return getMessageIdFromRootHash(g, timestamp, rootHash);
+	}
+
+	private MessageId getMessageIdFromRootHash(GroupId g, long timestamp,
+			byte[] rootHash) {
 		byte[] timeBytes = new byte[INT_64_BYTES];
 		ByteUtils.writeUint64(timestamp, timeBytes, 0);
 		byte[] idHash = crypto.hash(ID_LABEL, FORMAT_VERSION_BYTES,
@@ -65,7 +72,7 @@ class MessageFactoryImpl implements MessageFactory {
 		long timestamp = ByteUtils.readUint64(raw, UniqueId.LENGTH);
 		byte[] body = new byte[raw.length - MESSAGE_HEADER_LENGTH];
 		System.arraycopy(raw, MESSAGE_HEADER_LENGTH, body, 0, body.length);
-		MessageId id = getMessageId(g, timestamp, body);
+		MessageId id = getMessageIdFromBody(g, timestamp, body);
 		return new Message(id, g, timestamp, body);
 	}
 
@@ -78,4 +85,10 @@ class MessageFactoryImpl implements MessageFactory {
 		System.arraycopy(body, 0, raw, MESSAGE_HEADER_LENGTH, body.length);
 		return raw;
 	}
+
+	@Override
+	public MessageId getMessageId(GroupId g, long timestamp,
+			TreeHash rootHash) {
+		return getMessageIdFromRootHash(g, timestamp, rootHash.getBytes());
+	}
 }

bramble-core/src/main/java/org/briarproject/bramble/sync/tree/HashTree.java

@@ -0,0 +1,16 @@
+package org.briarproject.bramble.sync.tree;
+
+import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
+import org.briarproject.bramble.api.sync.tree.LeafNode;
+import org.briarproject.bramble.api.sync.tree.TreeNode;
+
+import javax.annotation.concurrent.NotThreadSafe;
+
+@NotThreadSafe
+@NotNullByDefault
+interface HashTree {
+
+	void addLeaf(LeafNode leaf);
+
+	TreeNode getRoot();
+}

bramble-core/src/main/java/org/briarproject/bramble/sync/tree/HashTreeImpl.java

@@ -0,0 +1,46 @@
+package org.briarproject.bramble.sync.tree;
+
+import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
+import org.briarproject.bramble.api.sync.tree.LeafNode;
+import org.briarproject.bramble.api.sync.tree.TreeHasher;
+import org.briarproject.bramble.api.sync.tree.TreeNode;
+
+import java.util.Deque;
+import java.util.LinkedList;
+
+import javax.inject.Inject;
+
+@NotNullByDefault
+class HashTreeImpl implements HashTree {
+
+	private final TreeHasher treeHasher;
+	private final Deque<TreeNode> nodes = new LinkedList<>();
+
+	@Inject
+	HashTreeImpl(TreeHasher treeHasher) {
+		this.treeHasher = treeHasher;
+	}
+
+	@Override
+	public void addLeaf(LeafNode leaf) {
+		TreeNode add = leaf;
+		int height = leaf.getHeight();
+		TreeNode last = nodes.peekLast();
+		while (last != null && last.getHeight() == height) {
+			add = treeHasher.mergeTrees(last, add);
+			height = add.getHeight();
+			nodes.removeLast();
+			last = nodes.peekLast();
+		}
+		nodes.addLast(add);
+	}
+
+	@Override
+	public TreeNode getRoot() {
+		TreeNode root = nodes.removeLast();
+		while (!nodes.isEmpty()) {
+			root = treeHasher.mergeTrees(nodes.removeLast(), root);
+		}
+		return root;
+	}
+}

bramble-core/src/main/java/org/briarproject/bramble/sync/tree/StreamHasherImpl.java

@@ -0,0 +1,85 @@
+package org.briarproject.bramble.sync.tree;
+
+import org.briarproject.bramble.api.db.DbException;
+import org.briarproject.bramble.api.io.BlockSink;
+import org.briarproject.bramble.api.io.HashingId;
+import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
+import org.briarproject.bramble.api.sync.tree.StreamHasher;
+import org.briarproject.bramble.api.sync.tree.TreeHash;
+import org.briarproject.bramble.api.sync.tree.TreeHasher;
+import org.briarproject.bramble.api.sync.tree.TreeNode;
+
+import java.io.IOException;
+import java.io.InputStream;
+import java.util.LinkedList;
+
+import javax.annotation.concurrent.Immutable;
+import javax.inject.Inject;
+import javax.inject.Provider;
+
+import static java.util.Arrays.copyOfRange;
+import static org.briarproject.bramble.api.sync.SyncConstants.MAX_BLOCK_LENGTH;
+
+@Immutable
+@NotNullByDefault
+class StreamHasherImpl implements StreamHasher {
+
+	private final TreeHasher treeHasher;
+	private final Provider<HashTree> hashTreeProvider;
+
+	@Inject
+	StreamHasherImpl(TreeHasher treeHasher,
+			Provider<HashTree> hashTreeProvider) {
+		this.treeHasher = treeHasher;
+		this.hashTreeProvider = hashTreeProvider;
+	}
+
+	@Override
+	public TreeNode hash(InputStream in, BlockSink sink, HashingId h)
+			throws IOException, DbException {
+		HashTree tree = hashTreeProvider.get();
+		byte[] block = new byte[MAX_BLOCK_LENGTH];
+		int read;
+		for (int blockNumber = 0; (read = read(in, block)) > 0; blockNumber++) {
+			byte[] data;
+			if (read == block.length) data = block;
+			else data = copyOfRange(block, 0, read);
+			sink.putBlock(h, blockNumber, data);
+			tree.addLeaf(treeHasher.hashBlock(blockNumber, data));
+		}
+		TreeNode root = tree.getRoot();
+		setPaths(sink, h, root, new LinkedList<>());
+		return root;
+	}
+
+	/**
+	 * Reads a block from the given input stream and returns the number of
+	 * bytes read, or 0 if no bytes were read before reaching the end of the
+	 * stream.
+	 */
+	private int read(InputStream in, byte[] block) throws IOException {
+		int offset = 0;
+		while (offset < block.length) {
+			int read = in.read(block, offset, block.length - offset);
+			if (read == -1) return offset;
+			offset += read;
+		}
+		return offset;
+	}
+
+	private void setPaths(BlockSink sink, HashingId h, TreeNode node,
+			LinkedList<TreeHash> path) throws DbException {
+		if (node.getHeight() == 0) {
+			// We've reached a leaf - store the path
+			sink.setPath(h, node.getFirstBlockNumber(), path);
+		} else {
+			// Add the right child's hash to the path and traverse the left
+			path.addFirst(node.getRightChild().getHash());
+			setPaths(sink, h, node.getLeftChild(), path);
+			// Add the left child's hash to the path and traverse the right
+			path.removeFirst();
+			path.addFirst(node.getLeftChild().getHash());
+			setPaths(sink, h, node.getRightChild(), path);
+		}
+	}
+}

bramble-core/src/main/java/org/briarproject/bramble/sync/tree/TreeHasherImpl.java

@@ -0,0 +1,44 @@
+package org.briarproject.bramble.sync.tree;
+
+import org.briarproject.bramble.api.crypto.CryptoComponent;
+import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
+import org.briarproject.bramble.api.sync.tree.LeafNode;
+import org.briarproject.bramble.api.sync.tree.ParentNode;
+import org.briarproject.bramble.api.sync.tree.TreeHash;
+import org.briarproject.bramble.api.sync.tree.TreeHasher;
+import org.briarproject.bramble.api.sync.tree.TreeNode;
+
+import javax.annotation.concurrent.Immutable;
+import javax.inject.Inject;
+
+import static org.briarproject.bramble.api.sync.Message.FORMAT_VERSION;
+import static org.briarproject.bramble.api.sync.MessageId.BLOCK_LABEL;
+import static org.briarproject.bramble.api.sync.MessageId.TREE_LABEL;
+
+@Immutable
+@NotNullByDefault
+class TreeHasherImpl implements TreeHasher {
+
+	private static final byte[] FORMAT_VERSION_BYTES =
+			new byte[] {FORMAT_VERSION};
+
+	private final CryptoComponent crypto;
+
+	@Inject
+	TreeHasherImpl(CryptoComponent crypto) {
+		this.crypto = crypto;
+	}
+
+	@Override
+	public LeafNode hashBlock(int blockNumber, byte[] data) {
+		byte[] hash = crypto.hash(BLOCK_LABEL, FORMAT_VERSION_BYTES, data);
+		return new LeafNode(new TreeHash(hash), blockNumber);
+	}
+
+	@Override
+	public ParentNode mergeTrees(TreeNode left, TreeNode right) {
+		byte[] hash = crypto.hash(TREE_LABEL, FORMAT_VERSION_BYTES,
+				left.getHash().getBytes(), right.getHash().getBytes());
+		return new ParentNode(new TreeHash(hash), left, right);
+	}
+}

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

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

bramble-core/src/test/java/org/briarproject/bramble/PriorityExecutorTest.java

@@ -1,86 +0,0 @@
-package org.briarproject.bramble;
-
-import org.briarproject.bramble.test.BrambleTestCase;
-import org.junit.Test;
-
-import java.util.List;
-import java.util.Vector;
-import java.util.concurrent.CountDownLatch;
-import java.util.concurrent.Executor;
-
-import static java.util.Arrays.asList;
-import static java.util.concurrent.Executors.newSingleThreadExecutor;
-import static org.junit.Assert.assertEquals;
-import static org.junit.Assert.fail;
-
-public class PriorityExecutorTest extends BrambleTestCase {
-
-	@Test
-	public void testHighPriorityTasksAreDelegatedInOrderOfSubmission()
-			throws Exception {
-		Executor delegate = newSingleThreadExecutor();
-		PriorityExecutor priority = new PriorityExecutor(delegate);
-		Executor high = priority.getHighPriorityExecutor();
-		testTasksAreDelegatedInOrderOfSubmission(high);
-	}
-
-	@Test
-	public void testLowPriorityTasksAreDelegatedInOrderOfSubmission()
-			throws Exception {
-		Executor delegate = newSingleThreadExecutor();
-		PriorityExecutor priority = new PriorityExecutor(delegate);
-		Executor low = priority.getLowPriorityExecutor();
-		testTasksAreDelegatedInOrderOfSubmission(low);
-	}
-
-	@Test
-	public void testHighPriorityTasksAreRunFirst() throws Exception {
-		Executor delegate = newSingleThreadExecutor();
-		PriorityExecutor priority = new PriorityExecutor(delegate);
-		Executor high = priority.getHighPriorityExecutor();
-		Executor low = priority.getLowPriorityExecutor();
-		// Submit a task that will block, causing other tasks to be queued
-		CountDownLatch cork = new CountDownLatch(1);
-		low.execute(() -> {
-			try {
-				cork.await();
-			} catch (InterruptedException e) {
-				fail();
-			}
-		});
-		// Submit alternating tasks to the high and low priority executors
-		List<Integer> results = new Vector<>();
-		CountDownLatch tasksFinished = new CountDownLatch(10);
-		for (int i = 0; i < 10; i++) {
-			int result = i;
-			Runnable task = () -> {
-				results.add(result);
-				tasksFinished.countDown();
-			};
-			if (i % 2 == 0) high.execute(task);
-			else low.execute(task);
-		}
-		// Release the cork and wait for all tasks to finish
-		cork.countDown();
-		tasksFinished.await();
-		// The high-priority tasks should have run before the low-priority tasks
-		assertEquals(asList(0, 2, 4, 6, 8, 1, 3, 5, 7, 9), results);
-	}
-
-	private void testTasksAreDelegatedInOrderOfSubmission(Executor e)
-			throws Exception {
-		List<Integer> results = new Vector<>();
-		CountDownLatch tasksFinished = new CountDownLatch(10);
-		for (int i = 0; i < 10; i++) {
-			int result = i;
-			e.execute(() -> {
-				results.add(result);
-				tasksFinished.countDown();
-			});
-		}
-		// Wait for all the tasks to finish
-		tasksFinished.await();
-		// The tasks should have run in the order they were submitted
-		assertEquals(asList(0, 1, 2, 3, 4, 5, 6, 7, 8, 9), results);
-	}
-}

bramble-core/src/test/java/org/briarproject/bramble/test/TestMessageFactory.java

@@ -4,6 +4,8 @@ import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
 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.bramble.api.sync.tree.TreeHash;
 
 import static org.briarproject.bramble.api.sync.SyncConstants.MESSAGE_HEADER_LENGTH;
 
@@ -27,4 +29,10 @@ public class TestMessageFactory implements MessageFactory {
 		System.arraycopy(body, 0, raw, MESSAGE_HEADER_LENGTH, body.length);
 		return raw;
 	}
+
+	@Override
+	public MessageId getMessageId(GroupId g, long timestamp,
+			TreeHash rootHash) {
+		throw new UnsupportedOperationException();
+	}
 }

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

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

briar-android/build.gradle

@@ -116,7 +116,7 @@ dependencies {
 	implementation 'info.guardianproject.trustedintents:trustedintents:0.2'
 	implementation 'de.hdodenhof:circleimageview:2.2.0'
 	implementation 'com.google.zxing:core:3.3.3'
-	implementation 'uk.co.samuelwall:material-tap-target-prompt:2.14.0'
+	implementation 'uk.co.samuelwall:material-tap-target-prompt:2.12.4'
 	implementation 'com.vanniktech:emoji-google:0.5.1'
 	def glideVersion = '4.8.0'
 	implementation("com.github.bumptech.glide:glide:$glideVersion") {
@@ -134,7 +134,7 @@ dependencies {
 	testImplementation project(path: ':bramble-core', configuration: 'testOutput')
 	testImplementation 'org.robolectric:robolectric:4.0.1'
 	testImplementation 'org.robolectric:shadows-support-v4:3.3.2'
-	testImplementation 'org.mockito:mockito-core:2.19.0'
+	testImplementation 'org.mockito:mockito-core:2.13.0'
 	testImplementation 'junit:junit:4.12'
 	testImplementation "org.jmock:jmock:2.8.2"
 	testImplementation "org.jmock:jmock-junit4:2.8.2"

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

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

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

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

briar-android/src/main/AndroidManifest.xml

@@ -1,7 +1,6 @@
 <?xml version="1.0" encoding="utf-8"?>
 <manifest
 	package="org.briarproject.briar"
-	xmlns:tools="http://schemas.android.com/tools"
 	xmlns:android="http://schemas.android.com/apk/res/android">
 
 	<uses-feature android:name="android.hardware.bluetooth" android:required="false"/>
@@ -18,7 +17,6 @@
 	<uses-permission android:name="android.permission.USE_FINGERPRINT"/>
 	<uses-permission android:name="android.permission.VIBRATE" />
 	<uses-permission android:name="android.permission.WAKE_LOCK" />
-	<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
 	<uses-permission-sdk-23 android:name="android.permission.ACCESS_COARSE_LOCATION" />
 	<uses-permission-sdk-23 android:name="android.permission.REQUEST_IGNORE_BATTERY_OPTIMIZATIONS"/>
 	<uses-permission-sdk-23 android:name="android.permission.USE_BIOMETRIC" />
@@ -30,8 +28,7 @@
 		android:label="@string/app_name"
 		android:logo="@mipmap/ic_launcher_round"
 		android:supportsRtl="true"
-		android:theme="@style/BriarTheme"
-		tools:ignore="GoogleAppIndexingWarning">
+		android:theme="@style/BriarTheme">
 
 		<receiver
 			android:name="org.briarproject.briar.android.login.SignInReminderReceiver"
@@ -119,7 +116,7 @@
 		<activity
 			android:name=".android.conversation.ImageActivity"
 			android:parentActivityName="org.briarproject.briar.android.conversation.ConversationActivity"
-			android:theme="@style/BriarTheme.ActionBarOverlay">
+			android:theme="@style/BriarTheme.Transparent.NoActionBar">
 			<meta-data
 				android:name="android.support.PARENT_ACTIVITY"
 				android:value="org.briarproject.briar.android.conversation.ConversationActivity"/>
@@ -157,7 +154,7 @@
 				android:value="org.briarproject.briar.android.navdrawer.NavDrawerActivity"/>
 		</activity>
 
-		<activity
+			<activity
 			android:name="org.briarproject.briar.android.privategroup.memberlist.GroupMemberListActivity"
 			android:label="@string/groups_member_list"
 			android:parentActivityName="org.briarproject.briar.android.privategroup.conversation.GroupActivity"
@@ -400,7 +397,7 @@
 		<activity
 			android:name="org.briarproject.briar.android.panic.PanicResponderActivity"
 			android:noHistory="true"
-			android:theme="@style/TranslucentTheme">
+			android:theme="@style/Theme.AppCompat.NoActionBar">
 			<!-- this can never have launchMode singleTask or singleInstance! -->
 			<intent-filter>
 				<action android:name="info.guardianproject.panic.action.TRIGGER"/>
@@ -410,12 +407,12 @@
 
 		<activity
 			android:name="org.briarproject.briar.android.logout.ExitActivity"
-			android:theme="@android:style/Theme.NoDisplay">
+			android:theme="@style/Theme.AppCompat.NoActionBar">
 		</activity>
 
 		<activity
 			android:name=".android.logout.HideUiActivity"
-			android:theme="@android:style/Theme.NoDisplay">
+			android:theme="@style/Theme.AppCompat.NoActionBar">
 		</activity>
 
 		<activity

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

@@ -43,7 +43,6 @@ import javax.inject.Inject;
 import static android.app.Activity.RESULT_OK;
 import static android.content.Intent.FLAG_ACTIVITY_CLEAR_TOP;
 import static android.widget.Toast.LENGTH_SHORT;
-import static java.util.Objects.requireNonNull;
 import static org.briarproject.briar.android.activity.BriarActivity.GROUP_ID;
 import static org.briarproject.briar.android.activity.RequestCodes.REQUEST_SHARE_BLOG;
 import static org.briarproject.briar.android.activity.RequestCodes.REQUEST_WRITE_BLOG_POST;
@@ -70,6 +69,7 @@ public class BlogFragment extends BaseFragment
 	private boolean isMyBlog = false, canDeleteBlog = false;
 
 	static BlogFragment newInstance(GroupId groupId) {
+
 		BlogFragment f = new BlogFragment();
 
 		Bundle bundle = new Bundle();
@@ -79,27 +79,20 @@ public class BlogFragment extends BaseFragment
 		return f;
 	}
 
-	@Override
-	public void injectFragment(ActivityComponent component) {
-		component.inject(this);
-		blogController.setBlogSharingListener(this);
-		sharingController.setSharingListener(this);
-	}
-
 	@Nullable
 	@Override
 	public View onCreateView(LayoutInflater inflater,
 			@Nullable ViewGroup container,
 			@Nullable Bundle savedInstanceState) {
-		Bundle args = requireNonNull(getArguments());
+		Bundle args = getArguments();
 		byte[] b = args.getByteArray(GROUP_ID);
 		if (b == null) throw new IllegalStateException("No group ID in args");
 		groupId = new GroupId(b);
 
 		View v = inflater.inflate(R.layout.fragment_blog, container, false);
 
-		adapter = new BlogPostAdapter(requireNonNull(getActivity()), this,
-				getFragmentManager());
+		adapter =
+				new BlogPostAdapter(getActivity(), this, getFragmentManager());
 		list = v.findViewById(R.id.postList);
 		list.setLayoutManager(new LinearLayoutManager(getActivity()));
 		list.setAdapter(adapter);
@@ -109,6 +102,13 @@ public class BlogFragment extends BaseFragment
 		return v;
 	}
 
+	@Override
+	public void injectFragment(ActivityComponent component) {
+		component.inject(this);
+		blogController.setBlogSharingListener(this);
+		sharingController.setSharingListener(this);
+	}
+
 	@Override
 	public void onStart() {
 		super.onStart();
@@ -218,10 +218,7 @@ public class BlogFragment extends BaseFragment
 
 	@Override
 	public void onAuthorClick(BlogPostItem post) {
-		if (post.getGroupId().equals(groupId) || getContext() == null) {
-			// We're already there
-			return;
-		}
+		if (post.getGroupId().equals(groupId)) return; // We're already there
 		Intent i = new Intent(getContext(), BlogActivity.class);
 		i.putExtra(GROUP_ID, post.getGroupId().getBytes());
 		i.setFlags(FLAG_ACTIVITY_CLEAR_TOP);

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

@@ -35,7 +35,6 @@ import javax.inject.Inject;
 import static android.app.Activity.RESULT_OK;
 import static android.content.Intent.FLAG_ACTIVITY_CLEAR_TOP;
 import static android.support.design.widget.Snackbar.LENGTH_LONG;
-import static java.util.Objects.requireNonNull;
 import static org.briarproject.briar.android.activity.BriarActivity.GROUP_ID;
 import static org.briarproject.briar.android.activity.RequestCodes.REQUEST_WRITE_BLOG_POST;
 
@@ -65,18 +64,13 @@ public class FeedFragment extends BaseFragment implements
 		return f;
 	}
 
-	@Override
-	public void injectFragment(ActivityComponent component) {
-		component.inject(this);
-		feedController.setFeedListener(this);
-	}
-
 	@Nullable
 	@Override
 	public View onCreateView(LayoutInflater inflater,
 			@Nullable ViewGroup container,
 			@Nullable Bundle savedInstanceState) {
-		requireNonNull(getActivity()).setTitle(R.string.blogs_button);
+
+		getActivity().setTitle(R.string.blogs_button);
 
 		View v = inflater.inflate(R.layout.fragment_blog, container, false);
 
@@ -94,6 +88,12 @@ public class FeedFragment extends BaseFragment implements
 		return v;
 	}
 
+	@Override
+	public void injectFragment(ActivityComponent component) {
+		component.inject(this);
+		feedController.setFeedListener(this);
+	}
+
 	@Override
 	public void onActivityResult(int requestCode, int resultCode, Intent data) {
 		super.onActivityResult(requestCode, resultCode, data);

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

@@ -1,14 +1,11 @@
 package org.briarproject.briar.android.conversation;
 
-import android.annotation.SuppressLint;
 import android.arch.lifecycle.Observer;
 import android.arch.lifecycle.ViewModelProvider;
 import android.arch.lifecycle.ViewModelProviders;
 import android.content.DialogInterface;
 import android.content.Intent;
-import android.net.Uri;
 import android.os.Bundle;
-import android.os.Parcelable;
 import android.support.annotation.Nullable;
 import android.support.annotation.UiThread;
 import android.support.design.widget.Snackbar;
@@ -30,6 +27,7 @@ import android.widget.ImageView;
 import android.widget.TextView;
 import android.widget.Toast;
 
+import org.briarproject.bramble.api.FormatException;
 import org.briarproject.bramble.api.Pair;
 import org.briarproject.bramble.api.contact.ContactId;
 import org.briarproject.bramble.api.contact.ContactManager;
@@ -46,11 +44,14 @@ import org.briarproject.bramble.api.nullsafety.ParametersNotNullByDefault;
 import org.briarproject.bramble.api.plugin.ConnectionRegistry;
 import org.briarproject.bramble.api.plugin.event.ContactConnectedEvent;
 import org.briarproject.bramble.api.plugin.event.ContactDisconnectedEvent;
+import org.briarproject.bramble.api.settings.Settings;
 import org.briarproject.bramble.api.settings.SettingsManager;
 import org.briarproject.bramble.api.sync.GroupId;
+import org.briarproject.bramble.api.sync.Message;
 import org.briarproject.bramble.api.sync.MessageId;
 import org.briarproject.bramble.api.sync.event.MessagesAckedEvent;
 import org.briarproject.bramble.api.sync.event.MessagesSentEvent;
+import org.briarproject.bramble.util.StringUtils;
 import org.briarproject.briar.R;
 import org.briarproject.briar.android.activity.ActivityComponent;
 import org.briarproject.briar.android.activity.BriarActivity;
@@ -61,12 +62,8 @@ import org.briarproject.briar.android.forum.ForumActivity;
 import org.briarproject.briar.android.introduction.IntroductionActivity;
 import org.briarproject.briar.android.privategroup.conversation.GroupActivity;
 import org.briarproject.briar.android.view.BriarRecyclerView;
-import org.briarproject.briar.android.view.ImagePreview;
-import org.briarproject.briar.android.view.TextAttachmentController;
-import org.briarproject.briar.android.view.TextAttachmentController.AttachImageListener;
 import org.briarproject.briar.android.view.TextInputView;
-import org.briarproject.briar.android.view.TextSendController;
-import org.briarproject.briar.android.view.TextSendController.SendListener;
+import org.briarproject.briar.android.view.TextInputView.TextInputListener;
 import org.briarproject.briar.api.android.AndroidNotificationManager;
 import org.briarproject.briar.api.blog.BlogSharingManager;
 import org.briarproject.briar.api.client.ProtocolStateException;
@@ -81,6 +78,7 @@ import org.briarproject.briar.api.introduction.IntroductionManager;
 import org.briarproject.briar.api.messaging.Attachment;
 import org.briarproject.briar.api.messaging.AttachmentHeader;
 import org.briarproject.briar.api.messaging.MessagingManager;
+import org.briarproject.briar.api.messaging.PrivateMessage;
 import org.briarproject.briar.api.messaging.PrivateMessageFactory;
 import org.briarproject.briar.api.messaging.PrivateMessageHeader;
 import org.briarproject.briar.api.privategroup.invitation.GroupInvitationManager;
@@ -102,12 +100,11 @@ import im.delight.android.identicons.IdenticonDrawable;
 import uk.co.samuelwall.materialtaptargetprompt.MaterialTapTargetPrompt;
 import uk.co.samuelwall.materialtaptargetprompt.MaterialTapTargetPrompt.PromptStateChangeListener;
 
-import static android.arch.lifecycle.Lifecycle.State.STARTED;
 import static android.os.Build.VERSION.SDK_INT;
 import static android.support.v4.app.ActivityOptionsCompat.makeSceneTransitionAnimation;
 import static android.support.v4.view.ViewCompat.setTransitionName;
 import static android.support.v7.util.SortedList.INVALID_POSITION;
-import static android.view.Gravity.RIGHT;
+import static android.view.Gravity.END;
 import static android.widget.Toast.LENGTH_SHORT;
 import static java.util.Collections.emptyList;
 import static java.util.Collections.sort;
@@ -117,14 +114,11 @@ import static java.util.logging.Level.WARNING;
 import static org.briarproject.bramble.util.LogUtils.logDuration;
 import static org.briarproject.bramble.util.LogUtils.logException;
 import static org.briarproject.bramble.util.LogUtils.now;
-import static org.briarproject.bramble.util.StringUtils.isNullOrEmpty;
-import static org.briarproject.briar.android.TestingConstants.FEATURE_FLAG_IMAGE_ATTACHMENTS;
-import static org.briarproject.briar.android.activity.RequestCodes.REQUEST_ATTACH_IMAGE;
 import static org.briarproject.briar.android.activity.RequestCodes.REQUEST_INTRODUCTION;
-import static org.briarproject.briar.android.conversation.ImageActivity.ATTACHMENTS;
-import static org.briarproject.briar.android.conversation.ImageActivity.ATTACHMENT_POSITION;
+import static org.briarproject.briar.android.conversation.ImageActivity.ATTACHMENT;
 import static org.briarproject.briar.android.conversation.ImageActivity.DATE;
 import static org.briarproject.briar.android.conversation.ImageActivity.NAME;
+import static org.briarproject.briar.android.settings.SettingsFragment.SETTINGS_NAMESPACE;
 import static org.briarproject.briar.android.util.UiUtils.getAvatarTransitionName;
 import static org.briarproject.briar.android.util.UiUtils.getBulbTransitionName;
 import static org.briarproject.briar.android.util.UiUtils.observeOnce;
@@ -135,16 +129,15 @@ import static uk.co.samuelwall.materialtaptargetprompt.MaterialTapTargetPrompt.S
 @MethodsNotNullByDefault
 @ParametersNotNullByDefault
 public class ConversationActivity extends BriarActivity
-		implements EventListener, ConversationListener, SendListener,
-		TextCache, AttachmentCache, AttachImageListener {
+		implements EventListener, ConversationListener, TextInputListener,
+		TextCache, AttachmentCache {
 
 	public static final String CONTACT_ID = "briar.CONTACT_ID";
 
 	private static final Logger LOG =
 			Logger.getLogger(ConversationActivity.class.getName());
-
-	private static final int TRANSITION_DURATION_MS = 500;
-	private static final int ONBOARDING_DELAY_MS = 250;
+	private static final String SHOW_ONBOARDING_INTRODUCTION =
+			"showOnboardingIntroduction";
 
 	@Inject
 	AndroidNotificationManager notificationManager;
@@ -153,8 +146,20 @@ public class ConversationActivity extends BriarActivity
 	@Inject
 	@CryptoExecutor
 	Executor cryptoExecutor;
-	@Inject
-	ViewModelProvider.Factory viewModelFactory;
+
+	private final Map<MessageId, String> textCache = new ConcurrentHashMap<>();
+	private AttachmentController attachmentController;
+
+	private ConversationViewModel viewModel;
+	private ConversationVisitor visitor;
+	private ConversationAdapter adapter;
+	private Toolbar toolbar;
+	private CircleImageView toolbarAvatar;
+	private ImageView toolbarStatus;
+	private TextView toolbarTitle;
+	private BriarRecyclerView list;
+	private LinearLayoutManager layoutManager;
+	private TextInputView textInputView;
 
 	// Fields that are accessed from background threads must be volatile
 	@Inject
@@ -177,37 +182,22 @@ public class ConversationActivity extends BriarActivity
 	volatile BlogSharingManager blogSharingManager;
 	@Inject
 	volatile GroupInvitationManager groupInvitationManager;
+	@Inject
+	ViewModelProvider.Factory viewModelFactory;
+
+	private volatile ContactId contactId;
+	@Nullable
+	private volatile GroupId messagingGroupId;
 
-	private final Map<MessageId, String> textCache = new ConcurrentHashMap<>();
 	private final Observer<String> contactNameObserver = name -> {
 		requireNonNull(name);
 		loadMessages();
 	};
 
-	private AttachmentController attachmentController;
-	private ConversationViewModel viewModel;
-	private ConversationVisitor visitor;
-	private ConversationAdapter adapter;
-	private Toolbar toolbar;
-	private CircleImageView toolbarAvatar;
-	private ImageView toolbarStatus;
-	private TextView toolbarTitle;
-	private BriarRecyclerView list;
-	private LinearLayoutManager layoutManager;
-	private TextInputView textInputView;
-	private TextSendController sendController;
-	@Nullable
-	private Parcelable layoutManagerState;
-
-	private volatile ContactId contactId;
-
 	@Override
 	public void onCreate(@Nullable Bundle state) {
 		if (SDK_INT >= 21) {
-			// Spurious lint warning - using END causes a crash
-			@SuppressLint("RtlHardcoded")
-			Transition slide = new Slide(RIGHT);
-			slide.setDuration(TRANSITION_DURATION_MS);
+			Transition slide = new Slide(END);
 			setSceneTransitionAnimation(slide, null, slide);
 		}
 		super.onCreate(state);
@@ -219,6 +209,7 @@ public class ConversationActivity extends BriarActivity
 
 		viewModel = ViewModelProviders.of(this, viewModelFactory)
 				.get(ConversationViewModel.class);
+		viewModel.setContactId(contactId);
 		attachmentController = viewModel.getAttachmentController();
 
 		setContentView(R.layout.activity_conversation);
@@ -242,8 +233,6 @@ public class ConversationActivity extends BriarActivity
 			requireNonNull(deleted);
 			if (deleted) finish();
 		});
-		viewModel.getAddedPrivateMessage().observe(this,
-				this::onAddedPrivateMessage);
 
 		setTransitionName(toolbarAvatar, getAvatarTransitionName(contactId));
 		setTransitionName(toolbarStatus, getBulbTransitionName(contactId));
@@ -258,29 +247,7 @@ public class ConversationActivity extends BriarActivity
 		list.setEmptyText(getString(R.string.no_private_messages));
 
 		textInputView = findViewById(R.id.text_input_container);
-		if (FEATURE_FLAG_IMAGE_ATTACHMENTS) {
-			ImagePreview imagePreview = findViewById(R.id.imagePreview);
-			sendController = new TextAttachmentController(textInputView,
-					imagePreview, this, this);
-			observeOnce(viewModel.hasImageSupport(), this, hasSupport -> {
-				if (hasSupport != null && hasSupport) {
-					// remove cast when removing FEATURE_FLAG_IMAGE_ATTACHMENTS
-					((TextAttachmentController) sendController)
-							.setImagesSupported();
-				}
-			});
-		} else {
-			sendController = new TextSendController(textInputView, this, false);
-		}
-		textInputView.setSendController(sendController);
-		textInputView.setMaxTextLength(MAX_PRIVATE_MESSAGE_TEXT_LENGTH);
-		textInputView.setEnabled(false);
-		textInputView.addOnKeyboardShownListener(this::scrollToBottom);
-	}
-
-	private void scrollToBottom() {
-		int items = adapter.getItemCount();
-		if (items > 0) list.scrollToPosition(items - 1);
+		textInputView.setListener(this);
 	}
 
 	@Override
@@ -289,8 +256,7 @@ public class ConversationActivity extends BriarActivity
 	}
 
 	@Override
-	protected void onActivityResult(int request, int result,
-			@Nullable Intent data) {
+	protected void onActivityResult(int request, int result, Intent data) {
 		super.onActivityResult(request, result, data);
 
 		if (request == REQUEST_INTRODUCTION && result == RESULT_OK) {
@@ -298,9 +264,6 @@ public class ConversationActivity extends BriarActivity
 					Snackbar.LENGTH_SHORT);
 			snackbar.getView().setBackgroundResource(R.color.briar_primary);
 			snackbar.show();
-		} else if (request == REQUEST_ATTACH_IMAGE && result == RESULT_OK) {
-			// remove cast when removing FEATURE_FLAG_IMAGE_ATTACHMENTS
-			((TextAttachmentController) sendController).onImageReceived(data);
 		}
 	}
 
@@ -315,16 +278,6 @@ public class ConversationActivity extends BriarActivity
 		list.startPeriodicUpdate();
 	}
 
-	@Override
-	public void onResume() {
-		super.onResume();
-		// Trigger loading of contact data, noop if data was loaded already.
-		//
-		// We can only start loading data *after* we are sure
-		// the user has signed in. After sign-in, onCreate() isn't run again.
-		if (signedIn()) viewModel.setContactId(contactId);
-	}
-
 	@Override
 	public void onStop() {
 		super.onStop();
@@ -334,39 +287,16 @@ public class ConversationActivity extends BriarActivity
 		list.stopPeriodicUpdate();
 	}
 
-	@Override
-	protected void onSaveInstanceState(Bundle outState) {
-		super.onSaveInstanceState(outState);
-		if (layoutManager != null) {
-			layoutManagerState = layoutManager.onSaveInstanceState();
-			outState.putParcelable("layoutManager", layoutManagerState);
-		}
-	}
-
-	@Override
-	protected void onRestoreInstanceState(Bundle savedInstanceState) {
-		super.onRestoreInstanceState(savedInstanceState);
-		layoutManagerState = savedInstanceState.getParcelable("layoutManager");
-	}
-
 	@Override
 	public boolean onCreateOptionsMenu(Menu menu) {
 		// Inflate the menu items for use in the action bar
 		MenuInflater inflater = getMenuInflater();
 		inflater.inflate(R.menu.conversation_actions, menu);
 
-		// enable introduction action if available
-		observeOnce(viewModel.showIntroductionAction(), this, enable -> {
-			if (enable != null && enable) {
-				menu.findItem(R.id.action_introduction).setEnabled(true);
-				// show introduction onboarding, if needed
-				observeOnce(viewModel.showIntroductionOnboarding(), this,
-						this::showIntroductionOnboarding);
-			}
-		});
-		// enable alias action if available
-		observeOnce(viewModel.getContact(), this, contact ->
-				menu.findItem(R.id.action_set_alias).setEnabled(true));
+		enableIntroductionActionIfAvailable(
+				menu.findItem(R.id.action_introduction));
+		enableAliasActionIfAvailable(
+				menu.findItem(R.id.action_set_alias));
 
 		return super.onCreateOptionsMenu(menu);
 	}
@@ -429,10 +359,33 @@ public class ConversationActivity extends BriarActivity
 						Long.compare(b.getTimestamp(), a.getTimestamp()));
 				if (!sorted.isEmpty()) {
 					// If the latest header is a private message, eagerly load
-					// its size so we can set the scroll position correctly
+					// its text so we can set the scroll position correctly
 					ConversationMessageHeader latest = sorted.get(0);
 					if (latest instanceof PrivateMessageHeader) {
-						eagerlyLoadMessageSize((PrivateMessageHeader) latest);
+						MessageId id = latest.getId();
+						PrivateMessageHeader h = (PrivateMessageHeader) latest;
+						if (h.hasText()) {
+							String text = textCache.get(id);
+							if (text == null) {
+								LOG.info(
+										"Eagerly loading text of latest message");
+								text = messagingManager.getMessageText(id);
+								textCache.put(id, text);
+							}
+						}
+						if (!h.getAttachmentHeaders().isEmpty()) {
+							List<AttachmentItem> items =
+									attachmentController.get(id);
+							if (items == null) {
+								LOG.info(
+										"Eagerly loading image size for latest message");
+								items = attachmentController.getAttachmentItems(
+										attachmentController
+												.getMessageAttachments(
+														h.getAttachmentHeaders()));
+								attachmentController.put(id, items);
+							}
+						}
 					}
 				}
 				displayMessages(revision, sorted);
@@ -444,51 +397,17 @@ public class ConversationActivity extends BriarActivity
 		});
 	}
 
-	private void eagerlyLoadMessageSize(PrivateMessageHeader h)
-			throws DbException {
-		MessageId id = h.getId();
-		// If the message has text, load it
-		if (h.hasText()) {
-			String text = textCache.get(id);
-			if (text == null) {
-				LOG.info("Eagerly loading text for latest message");
-				text = messagingManager.getMessageText(id);
-				textCache.put(id, text);
-			}
-		}
-		// If the message has a single image, load its size - for multiple
-		// images we use a grid so the size is fixed
-		if (h.getAttachmentHeaders().size() == 1) {
-			List<AttachmentItem> items = attachmentController.get(id);
-			if (items == null) {
-				LOG.info("Eagerly loading image size for latest message");
-				items = attachmentController.getAttachmentItems(
-						attachmentController.getMessageAttachments(
-								h.getAttachmentHeaders()));
-				attachmentController.put(id, items);
-			}
-		}
-	}
-
 	private void displayMessages(int revision,
 			Collection<ConversationMessageHeader> headers) {
 		runOnUiThreadUnlessDestroyed(() -> {
 			if (revision == adapter.getRevision()) {
 				adapter.incrementRevision();
-				textInputView.setEnabled(true);
-				// start observing onboarding after enabling (only once, because
-				// we only update this when an onboarding should be shown)
-				observeOnce(viewModel.showImageOnboarding(), this,
-						this::showImageOnboarding);
+				textInputView.setSendButtonEnabled(true);
 				List<ConversationItem> items = createItems(headers);
 				adapter.addAll(items);
 				list.showData();
-				if (layoutManagerState == null) {
-					scrollToBottom();
-				} else {
-					// Restore the previous scroll position
-					layoutManager.onRestoreInstanceState(layoutManagerState);
-				}
+				// Scroll to the bottom
+				list.scrollToPosition(adapter.getItemCount() - 1);
 			} else {
 				LOG.info("Concurrent update, reloading");
 				loadMessages();
@@ -529,28 +448,21 @@ public class ConversationActivity extends BriarActivity
 			Pair<Integer, ConversationMessageItem> pair =
 					adapter.getMessageItem(m);
 			if (pair != null) {
-				boolean scroll = shouldScrollWhenUpdatingMessage();
 				pair.getSecond().setText(text);
+				boolean bottom = adapter.isScrolledToBottom(layoutManager);
 				adapter.notifyItemChanged(pair.getFirst());
-				if (scroll) scrollToBottom();
+				if (bottom) list.scrollToPosition(adapter.getItemCount() - 1);
 			}
 		});
 	}
 
-	// When a message's text or attachments are loaded, scroll to the bottom
-	// if the conversation is visible and we were previously at the bottom
-	private boolean shouldScrollWhenUpdatingMessage() {
-		return getLifecycle().getCurrentState().isAtLeast(STARTED)
-				&& adapter.isScrolledToBottom(layoutManager);
-	}
-
 	private void loadMessageAttachments(MessageId messageId,
 			List<AttachmentHeader> headers) {
 		runOnDbThread(() -> {
 			try {
 				List<Pair<AttachmentHeader, Attachment>> attachments =
 						attachmentController.getMessageAttachments(headers);
-				// TODO move getting the items off to IoExecutor, if size == 1
+				// TODO move getting the items off to the IoExecutor
 				List<AttachmentItem> items =
 						attachmentController.getAttachmentItems(attachments);
 				displayMessageAttachments(messageId, items);
@@ -567,10 +479,10 @@ public class ConversationActivity extends BriarActivity
 			Pair<Integer, ConversationMessageItem> pair =
 					adapter.getMessageItem(m);
 			if (pair != null) {
-				boolean scroll = shouldScrollWhenUpdatingMessage();
 				pair.getSecond().setAttachments(items);
+				boolean bottom = adapter.isScrolledToBottom(layoutManager);
 				adapter.notifyItemChanged(pair.getFirst());
-				if (scroll) scrollToBottom();
+				if (bottom) list.scrollToPosition(adapter.getItemCount() - 1);
 			}
 		});
 	}
@@ -619,13 +531,10 @@ public class ConversationActivity extends BriarActivity
 
 	private void addConversationItem(ConversationItem item) {
 		runOnUiThreadUnlessDestroyed(() -> {
+			boolean bottom = adapter.isScrolledToBottom(layoutManager);
 			adapter.incrementRevision();
 			adapter.add(item);
-			// When adding a new message, scroll to the bottom if the
-			// conversation is visible, even if we're not currently at
-			// the bottom
-			if (getLifecycle().getCurrentState().isAtLeast(STARTED))
-				scrollToBottom();
+			if (bottom) list.scrollToPosition(adapter.getItemCount() - 1);
 		});
 	}
 
@@ -661,18 +570,14 @@ public class ConversationActivity extends BriarActivity
 	}
 
 	@Override
-	public void onAttachImage(Intent intent) {
-		startActivityForResult(intent, REQUEST_ATTACH_IMAGE);
-	}
-
-	@Override
-	public void onSendClick(@Nullable String text, List<Uri> imageUris) {
-		if (isNullOrEmpty(text) && imageUris.isEmpty())
-			throw new AssertionError();
+	public void onSendClick(String text) {
+		if (text.isEmpty()) return;
+		text = StringUtils.truncateUtf8(text, MAX_PRIVATE_MESSAGE_TEXT_LENGTH);
 		long timestamp = System.currentTimeMillis();
 		timestamp = Math.max(timestamp, getMinTimestampForNewMessage());
-		viewModel.sendMessage(text, imageUris, timestamp);
-		textInputView.clearText();
+		if (messagingGroupId == null) loadGroupId(text, timestamp);
+		else createMessage(text, timestamp);
+		textInputView.setText("");
 	}
 
 	private long getMinTimestampForNewMessage() {
@@ -681,10 +586,48 @@ public class ConversationActivity extends BriarActivity
 		return item == null ? 0 : item.getTime() + 1;
 	}
 
-	private void onAddedPrivateMessage(@Nullable PrivateMessageHeader h) {
-		if (h == null) return;
-		addConversationItem(h.accept(visitor));
-		viewModel.onAddedPrivateMessageSeen();
+	private void loadGroupId(String text, long timestamp) {
+		runOnDbThread(() -> {
+			try {
+				messagingGroupId =
+						messagingManager.getConversationId(contactId);
+				createMessage(text, timestamp);
+			} catch (DbException e) {
+				logException(LOG, WARNING, e);
+			}
+
+		});
+	}
+
+	private void createMessage(String text, long timestamp) {
+		cryptoExecutor.execute(() -> {
+			try {
+				//noinspection ConstantConditions init in loadGroupId()
+				storeMessage(privateMessageFactory.createPrivateMessage(
+						messagingGroupId, timestamp, text, emptyList()), text);
+			} catch (FormatException e) {
+				throw new RuntimeException(e);
+			}
+		});
+	}
+
+	private void storeMessage(PrivateMessage m, String text) {
+		runOnDbThread(() -> {
+			try {
+				long start = now();
+				messagingManager.addLocalMessage(m);
+				logDuration(LOG, "Storing message", start);
+				Message message = m.getMessage();
+				PrivateMessageHeader h = new PrivateMessageHeader(
+						message.getId(), message.getGroupId(),
+						message.getTimestamp(), true, false, false, false,
+						true, emptyList());
+				textCache.put(message.getId(), text);
+				addConversationItem(h.accept(visitor));
+			} catch (DbException e) {
+				logException(LOG, WARNING, e);
+			}
+		});
 	}
 
 	private void askToRemoveContact() {
@@ -721,70 +664,74 @@ public class ConversationActivity extends BriarActivity
 		});
 	}
 
-	private void showImageOnboarding(@Nullable Boolean show) {
-		if (show == null || !show) return;
-		if (SDK_INT >= 21) {
-			// show onboarding only after the enter transition has ended
-			// otherwise the tap target animation won't play
-			textInputView.postDelayed(this::showImageOnboarding,
-					TRANSITION_DURATION_MS + ONBOARDING_DELAY_MS);
-		} else {
-			showImageOnboarding();
-		}
+	private void enableIntroductionActionIfAvailable(MenuItem item) {
+		runOnDbThread(() -> {
+			try {
+				if (contactManager.getActiveContacts().size() > 1) {
+					enableIntroductionAction(item);
+					Settings settings =
+							settingsManager.getSettings(SETTINGS_NAMESPACE);
+					if (settings.getBoolean(SHOW_ONBOARDING_INTRODUCTION,
+							true)) {
+						showIntroductionOnboarding();
+					}
+				}
+			} catch (DbException e) {
+				logException(LOG, WARNING, e);
+			}
+		});
 	}
 
-	private void showImageOnboarding() {
-		// remove cast when removing FEATURE_FLAG_IMAGE_ATTACHMENTS
-		((TextAttachmentController) sendController)
-				.showImageOnboarding(this, () ->
-						viewModel.onImageOnboardingSeen());
+	private void enableAliasActionIfAvailable(MenuItem item) {
+		observeOnce(viewModel.getContact(), this, c -> item.setEnabled(true));
 	}
 
-	private void showIntroductionOnboarding(@Nullable Boolean show) {
-		if (show == null || !show) return;
-		if (SDK_INT >= 21) {
-			// show onboarding only after the enter transition has ended
-			// otherwise the tap target animation won't play
-			textInputView.postDelayed(this::showIntroductionOnboarding,
-					TRANSITION_DURATION_MS + ONBOARDING_DELAY_MS);
-		} else {
-			showIntroductionOnboarding();
-		}
+	private void enableIntroductionAction(MenuItem item) {
+		runOnUiThreadUnlessDestroyed(() -> item.setEnabled(true));
 	}
 
 	private void showIntroductionOnboarding() {
-		// find view of overflow icon
-		View target = null;
-		for (int i = 0; i < toolbar.getChildCount(); i++) {
-			if (toolbar.getChildAt(i) instanceof ActionMenuView) {
-				ActionMenuView menu = (ActionMenuView) toolbar.getChildAt(i);
-				// The overflow icon should be the last child of the menu
-				target = menu.getChildAt(menu.getChildCount() - 1);
-				// If the menu hasn't been populated yet, use the menu itself
-				// as the target
-				if (target == null) target = menu;
-				break;
+		runOnUiThreadUnlessDestroyed(() -> {
+			// find view of overflow icon
+			View target = null;
+			for (int i = 0; i < toolbar.getChildCount(); i++) {
+				if (toolbar.getChildAt(i) instanceof ActionMenuView) {
+					ActionMenuView menu =
+							(ActionMenuView) toolbar.getChildAt(i);
+					target = menu.getChildAt(menu.getChildCount() - 1);
+					break;
+				}
+			}
+			if (target == null) {
+				LOG.warning("No Overflow Icon found!");
+				return;
 			}
-		}
-		if (target == null) {
-			LOG.warning("No Overflow Icon found!");
-			return;
-		}
 
-		PromptStateChangeListener listener = (prompt, state) -> {
-			if (state == STATE_DISMISSED || state == STATE_FINISHED) {
-				viewModel.onIntroductionOnboardingSeen();
+			PromptStateChangeListener listener = (prompt, state) -> {
+				if (state == STATE_DISMISSED || state == STATE_FINISHED) {
+					introductionOnboardingSeen();
+				}
+			};
+			new MaterialTapTargetPrompt.Builder(ConversationActivity.this,
+					R.style.OnboardingDialogTheme).setTarget(target)
+					.setPrimaryText(R.string.introduction_onboarding_title)
+					.setSecondaryText(R.string.introduction_onboarding_text)
+					.setIcon(R.drawable.ic_more_vert_accent)
+					.setPromptStateChangeListener(listener)
+					.show();
+		});
+	}
+
+	private void introductionOnboardingSeen() {
+		runOnDbThread(() -> {
+			try {
+				Settings settings = new Settings();
+				settings.putBoolean(SHOW_ONBOARDING_INTRODUCTION, false);
+				settingsManager.mergeSettings(settings, SETTINGS_NAMESPACE);
+			} catch (DbException e) {
+				logException(LOG, WARNING, e);
 			}
-		};
-		new MaterialTapTargetPrompt.Builder(ConversationActivity.this,
-				R.style.OnboardingDialogTheme).setTarget(target)
-				.setPrimaryText(R.string.introduction_onboarding_title)
-				.setSecondaryText(R.string.introduction_onboarding_text)
-				.setIcon(R.drawable.ic_more_vert_accent)
-				.setBackgroundColour(
-						ContextCompat.getColor(this, R.color.briar_primary))
-				.setPromptStateChangeListener(listener)
-				.show();
+		});
 	}
 
 	@Override
@@ -878,18 +825,19 @@ public class ConversationActivity extends BriarActivity
 		} else {
 			name = getString(R.string.you);
 		}
-		ArrayList<AttachmentItem> attachments =
-				new ArrayList<>(messageItem.getAttachments());
 		Intent i = new Intent(this, ImageActivity.class);
-		i.putParcelableArrayListExtra(ATTACHMENTS, attachments);
-		i.putExtra(ATTACHMENT_POSITION, attachments.indexOf(item));
+		i.putExtra(ATTACHMENT, item);
 		i.putExtra(NAME, name);
 		i.putExtra(DATE, messageItem.getTime());
-		// restoring list position should not trigger android bug #224270
-		String transitionName = item.getTransitionName();
-		ActivityOptionsCompat options =
-				makeSceneTransitionAnimation(this, view, transitionName);
-		ActivityCompat.startActivity(this, i, options.toBundle());
+		if (SDK_INT >= 23) {
+			String transitionName = item.getTransitionName();
+			ActivityOptionsCompat options =
+					makeSceneTransitionAnimation(this, view, transitionName);
+			ActivityCompat.startActivity(this, i, options.toBundle());
+		} else {
+			// work-around for android bug #224270
+			startActivity(i);
+		}
 	}
 
 	@DatabaseExecutor

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

@@ -3,7 +3,6 @@ package org.briarproject.briar.android.conversation;
 import android.content.Context;
 import android.support.annotation.LayoutRes;
 import android.support.v7.widget.LinearLayoutManager;
-import android.support.v7.widget.RecyclerView.RecycledViewPool;
 import android.util.SparseArray;
 import android.view.LayoutInflater;
 import android.view.View;
@@ -22,17 +21,11 @@ class ConversationAdapter
 		extends BriarAdapter<ConversationItem, ConversationItemViewHolder> {
 
 	private ConversationListener listener;
-	private final RecycledViewPool imageViewPool;
-	private final ImageItemDecoration imageItemDecoration;
 
 	ConversationAdapter(Context ctx,
 			ConversationListener conversationListener) {
 		super(ctx, ConversationItem.class);
 		listener = conversationListener;
-		// This shares the same pool for view recycling between all image lists
-		imageViewPool = new RecycledViewPool();
-		// Share the item decoration as well
-		imageItemDecoration = new ImageItemDecoration(ctx);
 	}
 
 	@LayoutRes
@@ -49,17 +42,15 @@ class ConversationAdapter
 				type, viewGroup, false);
 		switch (type) {
 			case R.layout.list_item_conversation_msg_in:
-				return new ConversationMessageViewHolder(v, listener, true,
-						imageViewPool, imageItemDecoration);
+				return new ConversationMessageViewHolder(v, true);
 			case R.layout.list_item_conversation_msg_out:
-				return new ConversationMessageViewHolder(v, listener, false,
-						imageViewPool, imageItemDecoration);
+				return new ConversationMessageViewHolder(v, false);
 			case R.layout.list_item_conversation_notice_in:
-				return new ConversationNoticeViewHolder(v, listener, true);
+				return new ConversationNoticeViewHolder(v, true);
 			case R.layout.list_item_conversation_notice_out:
-				return new ConversationNoticeViewHolder(v, listener, false);
+				return new ConversationNoticeViewHolder(v, false);
 			case R.layout.list_item_conversation_request:
-				return new ConversationRequestViewHolder(v, listener, true);
+				return new ConversationRequestViewHolder(v, true);
 			default:
 				throw new IllegalArgumentException("Unknown ConversationItem");
 		}
@@ -68,7 +59,7 @@ class ConversationAdapter
 	@Override
 	public void onBindViewHolder(ConversationItemViewHolder ui, int position) {
 		ConversationItem item = items.get(position);
-		ui.bind(item);
+		ui.bind(item, listener);
 		listener.onItemVisible(item);
 	}
 

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

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

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

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

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

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

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

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

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

@@ -5,40 +5,19 @@ import android.arch.lifecycle.AndroidViewModel;
 import android.arch.lifecycle.LiveData;
 import android.arch.lifecycle.MutableLiveData;
 import android.arch.lifecycle.Transformations;
-import android.content.ContentResolver;
-import android.net.Uri;
 import android.support.annotation.Nullable;
-import android.support.annotation.UiThread;
 
-import org.briarproject.bramble.api.FormatException;
-import org.briarproject.bramble.api.Pair;
 import org.briarproject.bramble.api.contact.Contact;
 import org.briarproject.bramble.api.contact.ContactId;
 import org.briarproject.bramble.api.contact.ContactManager;
-import org.briarproject.bramble.api.crypto.CryptoExecutor;
-import org.briarproject.bramble.api.db.DatabaseComponent;
 import org.briarproject.bramble.api.db.DatabaseExecutor;
 import org.briarproject.bramble.api.db.DbException;
 import org.briarproject.bramble.api.db.NoSuchContactException;
 import org.briarproject.bramble.api.identity.AuthorId;
 import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
-import org.briarproject.bramble.api.settings.Settings;
-import org.briarproject.bramble.api.settings.SettingsManager;
-import org.briarproject.bramble.api.sync.GroupId;
-import org.briarproject.bramble.api.sync.Message;
 import org.briarproject.briar.android.util.UiUtils;
-import org.briarproject.briar.api.messaging.Attachment;
-import org.briarproject.briar.api.messaging.AttachmentHeader;
 import org.briarproject.briar.api.messaging.MessagingManager;
-import org.briarproject.briar.api.messaging.PrivateMessage;
-import org.briarproject.briar.api.messaging.PrivateMessageFactory;
-import org.briarproject.briar.api.messaging.PrivateMessageHeader;
 
-import java.io.IOException;
-import java.io.InputStream;
-import java.util.ArrayList;
-import java.util.Collection;
-import java.util.List;
 import java.util.concurrent.Executor;
 import java.util.logging.Logger;
 
@@ -47,34 +26,19 @@ import javax.inject.Inject;
 import static java.util.Objects.requireNonNull;
 import static java.util.logging.Level.WARNING;
 import static java.util.logging.Logger.getLogger;
-import static org.briarproject.bramble.util.IoUtils.tryToClose;
 import static org.briarproject.bramble.util.LogUtils.logDuration;
 import static org.briarproject.bramble.util.LogUtils.logException;
 import static org.briarproject.bramble.util.LogUtils.now;
-import static org.briarproject.briar.android.conversation.AttachmentDimensions.getAttachmentDimensions;
-import static org.briarproject.briar.android.settings.SettingsFragment.SETTINGS_NAMESPACE;
-import static org.briarproject.briar.android.util.UiUtils.observeForeverOnce;
 
 @NotNullByDefault
 public class ConversationViewModel extends AndroidViewModel {
 
 	private static Logger LOG =
 			getLogger(ConversationViewModel.class.getName());
-	private static final String SHOW_ONBOARDING_IMAGE =
-			"showOnboardingImage";
-	private static final String SHOW_ONBOARDING_INTRODUCTION =
-			"showOnboardingIntroduction";
 
 	@DatabaseExecutor
 	private final Executor dbExecutor;
-	@CryptoExecutor
-	private final Executor cryptoExecutor;
-	// TODO replace with TransactionManager once it exists
-	private final DatabaseComponent db;
-	private final MessagingManager messagingManager;
 	private final ContactManager contactManager;
-	private final SettingsManager settingsManager;
-	private final PrivateMessageFactory privateMessageFactory;
 	private final AttachmentController attachmentController;
 
 	@Nullable
@@ -84,64 +48,38 @@ public class ConversationViewModel extends AndroidViewModel {
 			Transformations.map(contact, c -> c.getAuthor().getId());
 	private final LiveData<String> contactName =
 			Transformations.map(contact, UiUtils::getContactDisplayName);
-	private final MutableLiveData<Boolean> imageSupport =
-			new MutableLiveData<>();
-	private final MutableLiveData<Boolean> showImageOnboarding =
-			new MutableLiveData<>();
-	private final MutableLiveData<Boolean> showIntroductionOnboarding =
-			new MutableLiveData<>();
-	private final MutableLiveData<Boolean> showIntroductionAction =
-			new MutableLiveData<>();
 	private final MutableLiveData<Boolean> contactDeleted =
 			new MutableLiveData<>();
-	private final MutableLiveData<GroupId> messagingGroupId =
-			new MutableLiveData<>();
-	private final MutableLiveData<PrivateMessageHeader> addedHeader =
-			new MutableLiveData<>();
 
 	@Inject
 	ConversationViewModel(Application application,
 			@DatabaseExecutor Executor dbExecutor,
-			@CryptoExecutor Executor cryptoExecutor, DatabaseComponent db,
-			MessagingManager messagingManager, ContactManager contactManager,
-			SettingsManager settingsManager,
-			PrivateMessageFactory privateMessageFactory) {
+			ContactManager contactManager, MessagingManager messagingManager) {
 		super(application);
 		this.dbExecutor = dbExecutor;
-		this.cryptoExecutor = cryptoExecutor;
-		this.db = db;
-		this.messagingManager = messagingManager;
 		this.contactManager = contactManager;
-		this.settingsManager = settingsManager;
-		this.privateMessageFactory = privateMessageFactory;
 		this.attachmentController = new AttachmentController(messagingManager,
-				getAttachmentDimensions(application.getResources()));
+				application.getResources());
 		contactDeleted.setValue(false);
 	}
 
-	/**
-	 * Setting the {@link ContactId} automatically triggers loading of other
-	 * data.
-	 */
 	void setContactId(ContactId contactId) {
 		if (this.contactId == null) {
 			this.contactId = contactId;
-			loadContact(contactId);
+			loadContact();
 		} else if (!contactId.equals(this.contactId)) {
 			throw new IllegalStateException();
 		}
 	}
 
-	private void loadContact(ContactId contactId) {
+	private void loadContact() {
 		dbExecutor.execute(() -> {
 			try {
 				long start = now();
-				Contact c = contactManager.getContact(contactId);
+				Contact c =
+						contactManager.getContact(requireNonNull(contactId));
 				contact.postValue(c);
 				logDuration(LOG, "Loading contact", start);
-				start = now();
-				checkFeaturesAndOnboarding(contactId);
-				logDuration(LOG, "Checking for image support", start);
 			} catch (NoSuchContactException e) {
 				contactDeleted.postValue(true);
 			} catch (DbException e) {
@@ -155,179 +93,13 @@ public class ConversationViewModel extends AndroidViewModel {
 			try {
 				contactManager.setContactAlias(requireNonNull(contactId),
 						alias.isEmpty() ? null : alias);
-				loadContact(contactId);
+				loadContact();
 			} catch (DbException e) {
 				logException(LOG, WARNING, e);
 			}
 		});
 	}
 
-	void sendMessage(@Nullable String text, List<Uri> uris, long timestamp) {
-		if (messagingGroupId.getValue() == null) loadGroupId();
-		observeForeverOnce(messagingGroupId, groupId -> {
-			if (groupId == null) return;
-			// calls through to creating and storing the message
-			storeAttachments(groupId, text, uris, timestamp);
-		});
-	}
-
-	private void loadGroupId() {
-		if (contactId == null) throw new IllegalStateException();
-		dbExecutor.execute(() -> {
-			try {
-				messagingGroupId.postValue(
-						messagingManager.getConversationId(contactId));
-			} catch (DbException e) {
-				logException(LOG, WARNING, e);
-			}
-		});
-	}
-
-	@DatabaseExecutor
-	private void checkFeaturesAndOnboarding(ContactId c) throws DbException {
-		// check if images are supported
-		boolean imagesSupported = db.transactionWithResult(true, txn ->
-				messagingManager.contactSupportsImages(txn, c));
-		imageSupport.postValue(imagesSupported);
-
-		// check if introductions are supported
-		Collection<Contact> contacts = contactManager.getActiveContacts();
-		boolean introductionSupported = contacts.size() > 1;
-		showIntroductionAction.postValue(introductionSupported);
-
-		Settings settings = settingsManager.getSettings(SETTINGS_NAMESPACE);
-		if (imagesSupported &&
-				settings.getBoolean(SHOW_ONBOARDING_IMAGE, true)) {
-			// check if we should show onboarding, only if images are supported
-			showImageOnboarding.postValue(true);
-			// allow observer to stop listening for changes
-			showIntroductionOnboarding.postValue(false);
-		} else {
-			// allow observer to stop listening for changes
-			showImageOnboarding.postValue(false);
-			// we only show one onboarding dialog at a time
-			if (introductionSupported &&
-					settings.getBoolean(SHOW_ONBOARDING_INTRODUCTION, true)) {
-				showIntroductionOnboarding.postValue(true);
-			} else {
-				// allow observer to stop listening for changes
-				showIntroductionOnboarding.postValue(false);
-			}
-		}
-	}
-
-	void onImageOnboardingSeen() {
-		onOnboardingSeen(SHOW_ONBOARDING_IMAGE);
-	}
-
-	void onIntroductionOnboardingSeen() {
-		onOnboardingSeen(SHOW_ONBOARDING_INTRODUCTION);
-	}
-
-	private void onOnboardingSeen(String key) {
-		dbExecutor.execute(() -> {
-			try {
-				Settings settings = new Settings();
-				settings.putBoolean(key, false);
-				settingsManager.mergeSettings(settings, SETTINGS_NAMESPACE);
-			} catch (DbException e) {
-				logException(LOG, WARNING, e);
-			}
-		});
-	}
-
-	private void storeAttachments(GroupId groupId, @Nullable String text,
-			List<Uri> uris, long timestamp) {
-		dbExecutor.execute(() -> {
-			long start = now();
-			List<AttachmentHeader> attachments = new ArrayList<>();
-			List<AttachmentItem> items = new ArrayList<>();
-			boolean needsSize = uris.size() == 1;
-			for (Uri uri : uris) {
-				Pair<AttachmentHeader, AttachmentItem> pair =
-						createAttachmentHeader(groupId, uri, timestamp,
-								needsSize);
-				if (pair == null) continue;
-				attachments.add(pair.getFirst());
-				items.add(pair.getSecond());
-			}
-			logDuration(LOG, "Storing attachments", start);
-			createMessage(groupId, text, attachments, items, timestamp);
-		});
-	}
-
-	@Nullable
-	@DatabaseExecutor
-	private Pair<AttachmentHeader, AttachmentItem> createAttachmentHeader(
-			GroupId groupId, Uri uri, long timestamp, boolean needsSize) {
-		InputStream is = null;
-		try {
-			ContentResolver contentResolver =
-					getApplication().getContentResolver();
-			is = contentResolver.openInputStream(uri);
-			if (is == null) throw new IOException();
-			String contentType = contentResolver.getType(uri);
-			if (contentType == null) throw new IOException("null content type");
-			AttachmentHeader h = messagingManager
-					.addLocalAttachment(groupId, timestamp, contentType, is);
-			is.close();
-			// re-open stream to get AttachmentItem
-			is = contentResolver.openInputStream(uri);
-			if (is == null) throw new IOException();
-			AttachmentItem item = attachmentController
-					.getAttachmentItem(h, new Attachment(is), needsSize);
-			return new Pair<>(h, item);
-		} catch (DbException | IOException e) {
-			logException(LOG, WARNING, e);
-			return null;
-		} finally {
-			if (is != null) tryToClose(is, LOG, WARNING);
-		}
-	}
-
-	private void createMessage(GroupId groupId, @Nullable String text,
-			List<AttachmentHeader> attachments, List<AttachmentItem> aItems,
-			long timestamp) {
-		cryptoExecutor.execute(() -> {
-			try {
-				// TODO remove when text can be null in the backend
-				String msgText = text == null ? "null" : text;
-				PrivateMessage pm = privateMessageFactory
-						.createPrivateMessage(groupId, timestamp, msgText,
-								attachments);
-				attachmentController.put(pm.getMessage().getId(), aItems);
-				storeMessage(pm, msgText, attachments);
-			} catch (FormatException e) {
-				throw new RuntimeException(e);
-			}
-		});
-	}
-
-	private void storeMessage(PrivateMessage m, @Nullable String text,
-			List<AttachmentHeader> attachments) {
-		dbExecutor.execute(() -> {
-			try {
-				long start = now();
-				messagingManager.addLocalMessage(m);
-				logDuration(LOG, "Storing message", start);
-				Message message = m.getMessage();
-				PrivateMessageHeader h = new PrivateMessageHeader(
-						message.getId(), message.getGroupId(),
-						message.getTimestamp(), true, true, false, false,
-						text != null, attachments);
-				// TODO add text to cache when available here
-				addedHeader.postValue(h);
-			} catch (DbException e) {
-				logException(LOG, WARNING, e);
-			}
-		});
-	}
-
-	@UiThread
-	void onAddedPrivateMessageSeen() {
-		addedHeader.setValue(null);
-	}
-
 	AttachmentController getAttachmentController() {
 		return attachmentController;
 	}
@@ -344,28 +116,8 @@ public class ConversationViewModel extends AndroidViewModel {
 		return contactName;
 	}
 
-	LiveData<Boolean> hasImageSupport() {
-		return imageSupport;
-	}
-
-	LiveData<Boolean> showImageOnboarding() {
-		return showImageOnboarding;
-	}
-
-	LiveData<Boolean> showIntroductionOnboarding() {
-		return showIntroductionOnboarding;
-	}
-
-	LiveData<Boolean> showIntroductionAction() {
-		return showIntroductionAction;
-	}
-
 	LiveData<Boolean> isContactDeleted() {
 		return contactDeleted;
 	}
 
-	LiveData<PrivateMessageHeader> getAddedPrivateMessage() {
-		return addedHeader;
-	}
-
 }

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

@@ -1,80 +1,54 @@
 package org.briarproject.briar.android.conversation;
 
-import android.arch.lifecycle.ViewModelProvider;
-import android.arch.lifecycle.ViewModelProviders;
-import android.content.DialogInterface.OnClickListener;
-import android.content.Intent;
+import android.graphics.drawable.Animatable;
 import android.graphics.drawable.Drawable;
 import android.os.Bundle;
 import android.support.annotation.Nullable;
 import android.support.annotation.RequiresApi;
 import android.support.design.widget.AppBarLayout;
-import android.support.design.widget.Snackbar;
-import android.support.v4.app.Fragment;
-import android.support.v4.app.FragmentManager;
-import android.support.v4.app.FragmentStatePagerAdapter;
-import android.support.v4.content.ContextCompat;
-import android.support.v4.graphics.drawable.DrawableCompat;
-import android.support.v4.view.ViewPager;
-import android.support.v7.app.AlertDialog.Builder;
 import android.support.v7.widget.Toolbar;
 import android.transition.Fade;
 import android.transition.Transition;
-import android.view.Menu;
 import android.view.MenuItem;
 import android.view.View;
-import android.view.ViewTreeObserver.OnGlobalLayoutListener;
 import android.view.Window;
 import android.widget.TextView;
 
-import org.briarproject.bramble.api.nullsafety.MethodsNotNullByDefault;
-import org.briarproject.bramble.api.nullsafety.ParametersNotNullByDefault;
+import com.bumptech.glide.load.DataSource;
+import com.bumptech.glide.load.engine.GlideException;
+import com.bumptech.glide.request.RequestListener;
+import com.bumptech.glide.request.target.Target;
+import com.github.chrisbanes.photoview.PhotoView;
+
 import org.briarproject.briar.R;
 import org.briarproject.briar.android.activity.ActivityComponent;
 import org.briarproject.briar.android.activity.BriarActivity;
+import org.briarproject.briar.android.conversation.glide.GlideApp;
 import org.briarproject.briar.android.view.PullDownLayout;
 
-import java.text.SimpleDateFormat;
-import java.util.Date;
-import java.util.List;
-import java.util.Locale;
-
-import javax.inject.Inject;
-
-import static android.content.Intent.ACTION_CREATE_DOCUMENT;
-import static android.content.Intent.CATEGORY_OPENABLE;
-import static android.content.Intent.EXTRA_TITLE;
 import static android.graphics.Color.TRANSPARENT;
 import static android.os.Build.VERSION.SDK_INT;
-import static android.support.design.widget.Snackbar.LENGTH_LONG;
 import static android.view.View.GONE;
 import static android.view.View.SYSTEM_UI_FLAG_FULLSCREEN;
 import static android.view.View.SYSTEM_UI_FLAG_LAYOUT_FULLSCREEN;
 import static android.view.View.SYSTEM_UI_FLAG_LAYOUT_STABLE;
 import static android.view.View.VISIBLE;
 import static android.view.WindowManager.LayoutParams.FLAG_TRANSLUCENT_STATUS;
+import static android.widget.ImageView.ScaleType.FIT_START;
+import static com.bumptech.glide.load.engine.DiskCacheStrategy.NONE;
 import static java.util.Objects.requireNonNull;
-import static org.briarproject.briar.android.activity.RequestCodes.REQUEST_SAVE_ATTACHMENT;
 import static org.briarproject.briar.android.util.UiUtils.formatDateAbsolute;
 
-@MethodsNotNullByDefault
-@ParametersNotNullByDefault
 public class ImageActivity extends BriarActivity
-		implements PullDownLayout.Callback, OnGlobalLayoutListener {
+		implements PullDownLayout.Callback {
 
-	final static String ATTACHMENTS = "attachments";
-	final static String ATTACHMENT_POSITION = "position";
+	final static String ATTACHMENT = "attachment";
 	final static String NAME = "name";
 	final static String DATE = "date";
 
-	@Inject
-	ViewModelProvider.Factory viewModelFactory;
-
-	private ImageViewModel viewModel;
 	private PullDownLayout layout;
 	private AppBarLayout appBarLayout;
-	private ViewPager viewPager;
-	private List<AttachmentItem> attachments;
+	private PhotoView photoView;
 
 	@Override
 	public void injectActivity(ActivityComponent component) {
@@ -86,23 +60,18 @@ public class ImageActivity extends BriarActivity
 		super.onCreate(state);
 
 		// Transitions
-		if (state == null) supportPostponeEnterTransition();
+		supportPostponeEnterTransition();
 		Window window = getWindow();
 		if (SDK_INT >= 21) {
 			Transition transition = new Fade();
 			setSceneTransitionAnimation(transition, null, transition);
 		}
 
-		// get View Model
-		viewModel = ViewModelProviders.of(this, viewModelFactory)
-				.get(ImageViewModel.class);
-		viewModel.getSaveState().observe(this, this::onImageSaveStateChanged);
-
 		// inflate layout
 		setContentView(R.layout.activity_image);
 		layout = findViewById(R.id.layout);
+		layout.getBackground().setAlpha(255);
 		layout.setCallback(this);
-		layout.getViewTreeObserver().addOnGlobalLayoutListener(this);
 
 		// Status Bar
 		if (SDK_INT >= 21) {
@@ -119,35 +88,59 @@ public class ImageActivity extends BriarActivity
 		TextView dateView = toolbar.findViewById(R.id.dateView);
 
 		// Intent Extras
-		Intent i = getIntent();
-		attachments = i.getParcelableArrayListExtra(ATTACHMENTS);
-		int position = i.getIntExtra(ATTACHMENT_POSITION, -1);
-		if (position == -1) throw new IllegalStateException();
-		String name = i.getStringExtra(NAME);
-		long time = i.getLongExtra(DATE, 0);
+		AttachmentItem attachment = getIntent().getParcelableExtra(ATTACHMENT);
+		String name = getIntent().getStringExtra(NAME);
+		long time = getIntent().getLongExtra(DATE, 0);
 		String date = formatDateAbsolute(this, time);
 		contactName.setText(name);
 		dateView.setText(date);
 
-		// Set up image ViewPager
-		viewPager = findViewById(R.id.viewPager);
-		ImagePagerAdapter pagerAdapter =
-				new ImagePagerAdapter(getSupportFragmentManager());
-		viewPager.setAdapter(pagerAdapter);
-		viewPager.setCurrentItem(position);
-
+		// Image View
+		photoView = findViewById(R.id.photoView);
 		if (SDK_INT >= 16) {
-			viewModel.getOnImageClicked().observe(this, this::onImageClicked);
+			photoView.setOnClickListener(view -> toggleSystemUi());
 			window.getDecorView().setSystemUiVisibility(
 					SYSTEM_UI_FLAG_LAYOUT_STABLE |
 							SYSTEM_UI_FLAG_LAYOUT_FULLSCREEN);
 		}
-	}
 
-	@Override
-	public boolean onCreateOptionsMenu(Menu menu) {
-		getMenuInflater().inflate(R.menu.image_actions, menu);
-		return super.onCreateOptionsMenu(menu);
+		// Request Listener
+		RequestListener<Drawable> listener = new RequestListener<Drawable>() {
+			@Override
+			public boolean onLoadFailed(@Nullable GlideException e,
+					Object model, Target<Drawable> target,
+					boolean isFirstResource) {
+				supportStartPostponedEnterTransition();
+				return false;
+			}
+
+			@Override
+			public boolean onResourceReady(Drawable resource, Object model,
+					Target<Drawable> target, DataSource dataSource,
+					boolean isFirstResource) {
+				if (SDK_INT >= 21 && !(resource instanceof Animatable)) {
+					// set transition name only when not animatable,
+					// because the animation won't start otherwise
+					photoView.setTransitionName(
+							attachment.getTransitionName());
+				}
+				// Move image to the top if overlapping toolbar
+				if (isOverlappingToolbar(resource)) {
+					photoView.setScaleType(FIT_START);
+				}
+				supportStartPostponedEnterTransition();
+				return false;
+			}
+		};
+
+		// Load Image
+		GlideApp.with(this)
+				.load(attachment)
+				.diskCacheStrategy(NONE)
+				.error(R.drawable.ic_image_broken)
+				.dontTransform()
+				.addListener(listener)
+				.into(photoView);
 	}
 
 	@Override
@@ -156,36 +149,11 @@ public class ImageActivity extends BriarActivity
 			case android.R.id.home:
 				onBackPressed();
 				return true;
-			case R.id.action_save_image:
-				showSaveImageDialog();
-				return true;
 			default:
 				return super.onOptionsItemSelected(item);
 		}
 	}
 
-	@Override
-	public void onGlobalLayout() {
-		viewModel.setToolbarPosition(
-				appBarLayout.getTop(), appBarLayout.getBottom()
-		);
-		if (SDK_INT >= 16) {
-			layout.getViewTreeObserver().removeOnGlobalLayoutListener(this);
-		} else {
-			layout.getViewTreeObserver().removeGlobalOnLayoutListener(this);
-		}
-	}
-
-	@Override
-	protected void onActivityResult(int request, int result,
-			@Nullable Intent data) {
-		super.onActivityResult(request, result, data);
-		if (request == REQUEST_SAVE_ATTACHMENT && result == RESULT_OK &&
-				data != null) {
-			viewModel.saveImage(getVisibleAttachment(), data.getData());
-		}
-	}
-
 	@Override
 	public void onPullStart() {
 		appBarLayout.animate()
@@ -195,6 +163,7 @@ public class ImageActivity extends BriarActivity
 
 	@Override
 	public void onPull(float progress) {
+		layout.getBackground().setAlpha(Math.round((1 - progress) * 255));
 	}
 
 	@Override
@@ -209,14 +178,6 @@ public class ImageActivity extends BriarActivity
 		supportFinishAfterTransition();
 	}
 
-	@RequiresApi(api = 16)
-	private void onImageClicked(@Nullable Boolean clicked) {
-		if (clicked != null && clicked) {
-			toggleSystemUi();
-			viewModel.onOnImageClickSeen();
-		}
-	}
-
 	@RequiresApi(api = 16)
 	private void toggleSystemUi() {
 		View decorView = getWindow().getDecorView();
@@ -229,8 +190,9 @@ public class ImageActivity extends BriarActivity
 
 	@RequiresApi(api = 16)
 	private void hideSystemUi(View decorView) {
-		decorView.setSystemUiVisibility(SYSTEM_UI_FLAG_FULLSCREEN |
-				SYSTEM_UI_FLAG_LAYOUT_STABLE | SYSTEM_UI_FLAG_LAYOUT_FULLSCREEN
+		decorView.setSystemUiVisibility(SYSTEM_UI_FLAG_LAYOUT_STABLE
+				| SYSTEM_UI_FLAG_LAYOUT_FULLSCREEN
+				| SYSTEM_UI_FLAG_FULLSCREEN
 		);
 		appBarLayout.animate()
 				.translationYBy(-1 * appBarLayout.getHeight())
@@ -242,7 +204,8 @@ public class ImageActivity extends BriarActivity
 	@RequiresApi(api = 16)
 	private void showSystemUi(View decorView) {
 		decorView.setSystemUiVisibility(
-				SYSTEM_UI_FLAG_LAYOUT_STABLE | SYSTEM_UI_FLAG_LAYOUT_FULLSCREEN
+				SYSTEM_UI_FLAG_LAYOUT_STABLE
+						| SYSTEM_UI_FLAG_LAYOUT_FULLSCREEN
 		);
 		appBarLayout.animate()
 				.translationYBy(appBarLayout.getHeight())
@@ -251,76 +214,20 @@ public class ImageActivity extends BriarActivity
 				.start();
 	}
 
-	private void showSaveImageDialog() {
-		OnClickListener okListener = (dialog, which) -> {
-			if (SDK_INT >= 19) {
-				Intent intent = getCreationIntent();
-				startActivityForResult(intent, REQUEST_SAVE_ATTACHMENT);
-			} else {
-				viewModel.saveImage(getVisibleAttachment());
-			}
-		};
-		Builder builder = new Builder(this, R.style.BriarDialogTheme);
-		builder.setTitle(getString(R.string.dialog_title_save_image));
-		builder.setMessage(getString(R.string.dialog_message_save_image));
-		Drawable icon = ContextCompat.getDrawable(this, R.drawable.ic_security);
-		DrawableCompat.setTint(requireNonNull(icon),
-				ContextCompat.getColor(this, R.color.color_primary));
-		builder.setIcon(icon);
-		builder.setPositiveButton(R.string.save_image, okListener);
-		builder.setNegativeButton(R.string.cancel, null);
-		builder.show();
-	}
-
-	@RequiresApi(api = 19)
-	private Intent getCreationIntent() {
-		SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd'T'HH:mm:ss",
-				Locale.getDefault());
-		String fileName = sdf.format(new Date());
-		Intent intent = new Intent(ACTION_CREATE_DOCUMENT);
-		intent.addCategory(CATEGORY_OPENABLE);
-		intent.setType(getVisibleAttachment().getMimeType());
-		intent.putExtra(EXTRA_TITLE, fileName);
-		return intent;
-	}
-
-	private void onImageSaveStateChanged(@Nullable Boolean error) {
-		if (error == null) return;
-		int stringRes = error ?
-				R.string.save_image_error : R.string.save_image_success;
-		int colorRes = error ?
-				R.color.briar_red : R.color.briar_primary;
-		Snackbar s = Snackbar.make(layout, stringRes, LENGTH_LONG);
-		s.getView().setBackgroundResource(colorRes);
-		s.show();
-		viewModel.onSaveStateSeen();
-	}
-
-	AttachmentItem getVisibleAttachment() {
-		return attachments.get(viewPager.getCurrentItem());
-	}
-
-	private class ImagePagerAdapter extends FragmentStatePagerAdapter {
-
-		private boolean isFirst = true;
-
-		private ImagePagerAdapter(FragmentManager fm) {
-			super(fm);
-		}
-
-		@Override
-		public Fragment getItem(int position) {
-			Fragment f = ImageFragment
-					.newInstance(attachments.get(position), isFirst);
-			isFirst = false;
-			return f;
-		}
-
-		@Override
-		public int getCount() {
-			return attachments.size();
-		}
-
+	private boolean isOverlappingToolbar(Drawable drawable) {
+		int width = drawable.getIntrinsicWidth();
+		int height = drawable.getIntrinsicHeight();
+		float widthPercentage = photoView.getWidth() / (float) width;
+		float heightPercentage = photoView.getHeight() / (float) height;
+		float scaleFactor = Math.min(widthPercentage, heightPercentage);
+		int realWidth = (int) (width * scaleFactor);
+		int realHeight = (int) (height * scaleFactor);
+		// return if photo doesn't use the full width,
+		// because it will be moved to the right otherwise
+		if (realWidth < photoView.getWidth()) return false;
+		int drawableTop = (photoView.getHeight() - realHeight) / 2;
+		return drawableTop < appBarLayout.getBottom() &&
+				drawableTop != appBarLayout.getTop();
 	}
 
 }

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

@@ -10,6 +10,7 @@ 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;
@@ -38,6 +39,11 @@ public class IntroFragment extends BaseFragment {
 		return fragment;
 	}
 
+	@Override
+	public void injectFragment(ActivityComponent component) {
+		component.inject(this);
+	}
+
 	@Override
 	public void onAttach(Context context) {
 		super.onAttach(context);

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

@@ -53,7 +53,6 @@ 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.Objects.requireNonNull;
 import static java.util.logging.Level.INFO;
 import static java.util.logging.Level.WARNING;
 import static org.briarproject.bramble.util.LogUtils.logException;
@@ -137,8 +136,7 @@ public class KeyAgreementFragment extends BaseEventFragment
 	@Override
 	public void onActivityCreated(@Nullable Bundle savedInstanceState) {
 		super.onActivityCreated(savedInstanceState);
-		requireNonNull(getActivity())
-				.setRequestedOrientation(SCREEN_ORIENTATION_NOSENSOR);
+		getActivity().setRequestedOrientation(SCREEN_ORIENTATION_NOSENSOR);
 		cameraView.setPreviewConsumer(new QrCodeDecoder(this));
 	}
 

briar-android/src/main/java/org/briarproject/briar/android/login/AuthorNameFragment.java

@@ -18,7 +18,6 @@ import javax.annotation.Nullable;
 
 import static android.view.inputmethod.EditorInfo.IME_ACTION_NEXT;
 import static android.view.inputmethod.EditorInfo.IME_ACTION_NONE;
-import static java.util.Objects.requireNonNull;
 import static org.briarproject.bramble.api.identity.AuthorConstants.MAX_AUTHOR_NAME_LENGTH;
 import static org.briarproject.briar.android.util.UiUtils.setError;
 
@@ -36,16 +35,11 @@ public class AuthorNameFragment extends SetupFragment {
 		return new AuthorNameFragment();
 	}
 
-	@Override
-	public void injectFragment(ActivityComponent component) {
-		component.inject(this);
-	}
-
 	@Override
 	public View onCreateView(LayoutInflater inflater,
 			@Nullable ViewGroup container,
 			@Nullable Bundle savedInstanceState) {
-		requireNonNull(getActivity()).setTitle(getString(R.string.setup_title));
+		getActivity().setTitle(getString(R.string.setup_title));
 		View v = inflater.inflate(R.layout.fragment_setup_author_name,
 				container, false);
 		authorNameWrapper = v.findViewById(R.id.nickname_entry_wrapper);
@@ -63,6 +57,11 @@ public class AuthorNameFragment extends SetupFragment {
 		return TAG;
 	}
 
+	@Override
+	public void injectFragment(ActivityComponent component) {
+		component.inject(this);
+	}
+
 	@Override
 	protected String getHelpText() {
 		return getString(R.string.setup_name_explanation);

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

@@ -19,7 +19,6 @@ import org.briarproject.briar.android.util.UiUtils;
 
 import static android.view.View.INVISIBLE;
 import static android.view.View.VISIBLE;
-import static java.util.Objects.requireNonNull;
 import static org.briarproject.briar.android.activity.RequestCodes.REQUEST_DOZE_WHITELISTING;
 import static org.briarproject.briar.android.util.UiUtils.showOnboardingDialog;
 
@@ -40,16 +39,11 @@ public class DozeFragment extends SetupFragment
 		return new DozeFragment();
 	}
 
-	@Override
-	public void injectFragment(ActivityComponent component) {
-		component.inject(this);
-	}
-
 	@Override
 	public View onCreateView(LayoutInflater inflater,
 			@Nullable ViewGroup container,
 			@Nullable Bundle savedInstanceState) {
-		requireNonNull(getActivity()).setTitle(getString(R.string.setup_doze_title));
+		getActivity().setTitle(getString(R.string.setup_doze_title));
 		setHasOptionsMenu(false);
 		View v = inflater.inflate(R.layout.fragment_setup_doze, container,
 						false);
@@ -71,6 +65,11 @@ public class DozeFragment extends SetupFragment
 		return TAG;
 	}
 
+	@Override
+	public void injectFragment(ActivityComponent component) {
+		component.inject(this);
+	}
+
 	@Override
 	protected String getHelpText() {
 		return getString(R.string.setup_doze_explanation);

briar-android/src/main/java/org/briarproject/briar/android/login/PasswordFragment.java

@@ -23,7 +23,6 @@ import static android.content.Context.INPUT_METHOD_SERVICE;
 import static android.view.View.INVISIBLE;
 import static android.view.View.VISIBLE;
 import static android.view.inputmethod.EditorInfo.IME_ACTION_DONE;
-import static java.util.Objects.requireNonNull;
 import static org.briarproject.bramble.api.crypto.PasswordStrengthEstimator.QUITE_WEAK;
 
 @MethodsNotNullByDefault
@@ -44,16 +43,11 @@ public class PasswordFragment extends SetupFragment {
 		return new PasswordFragment();
 	}
 
-	@Override
-	public void injectFragment(ActivityComponent component) {
-		component.inject(this);
-	}
-
 	@Override
 	public View onCreateView(LayoutInflater inflater,
 			@Nullable ViewGroup container,
 			@Nullable Bundle savedInstanceState) {
-		requireNonNull(getActivity()).setTitle(getString(R.string.setup_password_intro));
+		getActivity().setTitle(getString(R.string.setup_password_intro));
 		View v = inflater.inflate(R.layout.fragment_setup_password, container,
 						false);
 
@@ -70,11 +64,6 @@ public class PasswordFragment extends SetupFragment {
 		passwordConfirmation.addTextChangedListener(this);
 		nextButton.setOnClickListener(this);
 
-		if (!setupController.needToShowDozeFragment()) {
-			nextButton.setText(R.string.create_account_button);
-			passwordConfirmation.setImeOptions(IME_ACTION_DONE);
-		}
-
 		return v;
 	}
 
@@ -83,6 +72,17 @@ public class PasswordFragment extends SetupFragment {
 		return TAG;
 	}
 
+	@Override
+	public void injectFragment(ActivityComponent component) {
+		component.inject(this);
+
+		// the controller is not yet available in onCreateView()
+		if (!setupController.needToShowDozeFragment()) {
+			nextButton.setText(R.string.create_account_button);
+			passwordConfirmation.setImeOptions(IME_ACTION_DONE);
+		}
+	}
+
 	@Override
 	protected String getHelpText() {
 		return getString(R.string.setup_password_explanation);

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

@@ -11,8 +11,7 @@ import android.view.View.OnClickListener;
 import android.widget.TextView;
 import android.widget.TextView.OnEditorActionListener;
 
-import org.briarproject.bramble.api.nullsafety.MethodsNotNullByDefault;
-import org.briarproject.bramble.api.nullsafety.ParametersNotNullByDefault;
+import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
 import org.briarproject.briar.R;
 import org.briarproject.briar.android.fragment.BaseFragment;
 
@@ -23,8 +22,7 @@ import static android.view.inputmethod.EditorInfo.IME_ACTION_NEXT;
 import static org.briarproject.briar.android.util.UiUtils.enterPressed;
 import static org.briarproject.briar.android.util.UiUtils.showOnboardingDialog;
 
-@MethodsNotNullByDefault
-@ParametersNotNullByDefault
+@NotNullByDefault
 abstract class SetupFragment extends BaseFragment implements TextWatcher,
 		OnEditorActionListener, OnClickListener {
 

briar-android/src/main/java/org/briarproject/briar/android/logout/ExitActivity.java

@@ -1,13 +1,14 @@
 package org.briarproject.briar.android.logout;
 
-import android.app.Activity;
+import android.os.Build;
 import android.os.Bundle;
 
+import org.briarproject.briar.android.activity.ActivityComponent;
+import org.briarproject.briar.android.activity.BaseActivity;
+
 import java.util.logging.Logger;
 
-import static android.os.Build.VERSION.SDK_INT;
-
-public class ExitActivity extends Activity {
+public class ExitActivity extends BaseActivity {
 
 	private static final Logger LOG =
 			Logger.getLogger(ExitActivity.class.getName());
@@ -15,9 +16,14 @@ public class ExitActivity extends Activity {
 	@Override
 	public void onCreate(Bundle state) {
 		super.onCreate(state);
-		if (SDK_INT >= 21) finishAndRemoveTask();
+		if (Build.VERSION.SDK_INT >= 21) finishAndRemoveTask();
 		else finish();
 		LOG.info("Exiting");
 		System.exit(0);
 	}
+
+	@Override
+	public void injectActivity(ActivityComponent component) {
+
+	}
 }

briar-android/src/main/java/org/briarproject/briar/android/logout/HideUiActivity.java

@@ -1,13 +1,20 @@
 package org.briarproject.briar.android.logout;
 
-import android.app.Activity;
 import android.os.Bundle;
 
-public class HideUiActivity extends Activity {
+import org.briarproject.briar.android.activity.ActivityComponent;
+import org.briarproject.briar.android.activity.BaseActivity;
+
+public class HideUiActivity extends BaseActivity {
 
 	@Override
 	public void onCreate(Bundle state) {
 		super.onCreate(state);
 		finish();
 	}
+
+	@Override
+	public void injectActivity(ActivityComponent component) {
+
+	}
 }

briar-android/src/main/java/org/briarproject/briar/android/logout/SignOutFragment.java

@@ -5,21 +5,19 @@ import android.view.LayoutInflater;
 import android.view.View;
 import android.view.ViewGroup;
 
-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.Nonnull;
 import javax.annotation.Nullable;
 
-@MethodsNotNullByDefault
-@ParametersNotNullByDefault
 public class SignOutFragment extends BaseFragment {
 
 	public static final String TAG = SignOutFragment.class.getName();
 
 	@Override
-	public View onCreateView(LayoutInflater inflater,
+	public View onCreateView(@Nonnull LayoutInflater inflater,
 			@Nullable ViewGroup container,
 			@Nullable Bundle savedInstanceState) {
 		return inflater.inflate(R.layout.fragment_sign_out, container, false);
@@ -29,4 +27,9 @@ public class SignOutFragment extends BaseFragment {
 	public String getUniqueTag() {
 		return TAG;
 	}
+
+	@Override
+	public void injectFragment(ActivityComponent component) {
+		// no need to inject
+	}
 }

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

@@ -5,7 +5,6 @@ import android.content.Intent;
 import android.content.res.Configuration;
 import android.os.Bundle;
 import android.support.annotation.NonNull;
-import android.support.annotation.Nullable;
 import android.support.design.widget.NavigationView;
 import android.support.design.widget.NavigationView.OnNavigationItemSelectedListener;
 import android.support.v4.app.ActivityCompat;
@@ -13,7 +12,6 @@ import android.support.v4.app.FragmentManager;
 import android.support.v4.app.FragmentTransaction;
 import android.support.v4.content.ContextCompat;
 import android.support.v4.widget.DrawerLayout;
-import android.support.v7.app.ActionBar;
 import android.support.v7.app.ActionBarDrawerToggle;
 import android.support.v7.widget.Toolbar;
 import android.view.LayoutInflater;
@@ -27,8 +25,6 @@ import android.widget.TextView;
 
 import org.briarproject.bramble.api.db.DbException;
 import org.briarproject.bramble.api.lifecycle.LifecycleManager;
-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.TorConstants;
@@ -58,7 +54,6 @@ import static android.support.v4.view.GravityCompat.START;
 import static android.support.v4.widget.DrawerLayout.LOCK_MODE_LOCKED_CLOSED;
 import static android.view.View.GONE;
 import static android.view.View.VISIBLE;
-import static java.util.Objects.requireNonNull;
 import static org.briarproject.bramble.api.lifecycle.LifecycleManager.LifecycleState.RUNNING;
 import static org.briarproject.briar.android.BriarService.EXTRA_STARTUP_FAILED;
 import static org.briarproject.briar.android.activity.RequestCodes.REQUEST_PASSWORD;
@@ -66,8 +61,6 @@ import static org.briarproject.briar.android.navdrawer.NavDrawerController.Expir
 import static org.briarproject.briar.android.navdrawer.NavDrawerController.ExpiryWarning.UPDATE;
 import static org.briarproject.briar.android.util.UiUtils.getDaysUntilExpiry;
 
-@MethodsNotNullByDefault
-@ParametersNotNullByDefault
 public class NavDrawerActivity extends BriarActivity implements
 		BaseFragmentListener, TransportStateListener,
 		OnNavigationItemSelectedListener {
@@ -119,8 +112,9 @@ public class NavDrawerActivity extends BriarActivity implements
 		component.inject(this);
 	}
 
+	@SuppressWarnings("ConstantConditions")
 	@Override
-	public void onCreate(@Nullable Bundle state) {
+	public void onCreate(Bundle state) {
 		super.onCreate(state);
 		exitIfStartupFailed(getIntent());
 		setContentView(R.layout.activity_nav_drawer);
@@ -131,9 +125,8 @@ public class NavDrawerActivity extends BriarActivity implements
 		GridView transportsView = findViewById(R.id.transportsView);
 
 		setSupportActionBar(toolbar);
-		ActionBar actionBar = requireNonNull(getSupportActionBar());
-		actionBar.setDisplayHomeAsUpEnabled(true);
-		actionBar.setHomeButtonEnabled(true);
+		getSupportActionBar().setDisplayHomeAsUpEnabled(true);
+		getSupportActionBar().setHomeButtonEnabled(true);
 
 		drawerToggle = new ActionBarDrawerToggle(this, drawerLayout, toolbar,
 				R.string.nav_drawer_open_description,
@@ -172,8 +165,7 @@ public class NavDrawerActivity extends BriarActivity implements
 	}
 
 	@Override
-	protected void onActivityResult(int request, int result,
-			@Nullable Intent data) {
+	protected void onActivityResult(int request, int result, Intent data) {
 		super.onActivityResult(request, result, data);
 		if (request == REQUEST_PASSWORD && result == RESULT_OK) {
 			controller.shouldAskForDozeWhitelisting(this,
@@ -261,7 +253,7 @@ public class NavDrawerActivity extends BriarActivity implements
 	}
 
 	@Override
-	public void onPostCreate(@Nullable Bundle savedInstanceState) {
+	public void onPostCreate(Bundle savedInstanceState) {
 		super.onPostCreate(savedInstanceState);
 		drawerToggle.syncState();
 	}