DO NOT MERGE: Return multiple fake image attachements in MessagingManager

UX for displaying multiple image attachments

Closes #1473

See merge request briar/briar!1010

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

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

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

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

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

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

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

@@ -16,6 +16,7 @@ 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;
@@ -90,22 +91,44 @@ class AttachmentController {
 		return attachments;
 	}
 
+	/**
+	 * Creates {@link AttachmentItem}s from the passed headers and Attachments.
+	 *
+	 * Note: This closes the {@link Attachment}'s {@link InputStream}.
+	 */
 	List<AttachmentItem> getAttachmentItems(
 			List<Pair<AttachmentHeader, Attachment>> attachments) {
+		boolean needsSize = attachments.size() == 1;
 		List<AttachmentItem> items = new ArrayList<>(attachments.size());
 		for (Pair<AttachmentHeader, Attachment> a : attachments) {
 			AttachmentItem item =
-					getAttachmentItem(a.getFirst(), a.getSecond());
+					getAttachmentItem(a.getFirst(), a.getSecond(), needsSize);
 			items.add(item);
 		}
 		return items;
 	}
 
-	private AttachmentItem getAttachmentItem(AttachmentHeader h, Attachment a) {
+	/**
+	 * Creates an {@link AttachmentItem} from the {@link Attachment}'s
+	 * {@link InputStream} which will be closed when this method returns.
+	 */
+	AttachmentItem getAttachmentItem(AttachmentHeader h, Attachment a,
+			boolean needsSize) {
 		MessageId messageId = h.getMessageId();
-		Size size = new Size();
+		if (!needsSize) {
+			String mimeType = h.getContentType();
+			String extension = getExtensionFromMimeType(mimeType);
+			boolean hasError = false;
+			if (extension == null) {
+				extension = "";
+				hasError = true;
+			}
+			return new AttachmentItem(messageId, 0, 0, mimeType, extension, 0,
+					0, hasError);
+		}
 
-		InputStream is = a.getStream();
+		Size size = new Size();
+		InputStream is = new BufferedInputStream(a.getStream());
 		is.mark(Integer.MAX_VALUE);
 		try {
 			// use exif to get size
@@ -134,14 +157,19 @@ class AttachmentController {
 					getThumbnailSize(size.width, size.height, size.mimeType);
 		}
 		// get file extension
-		MimeTypeMap mimeTypeMap = MimeTypeMap.getSingleton();
-		String extension = mimeTypeMap.getExtensionFromMimeType(size.mimeType);
+		String extension = getExtensionFromMimeType(size.mimeType);
 		if (extension == null) {
 			return new AttachmentItem(messageId, 0, 0, "", "", 0, 0, true);
 		}
 		return new AttachmentItem(messageId, size.width, size.height,
-				size.mimeType, extension, thumbnailSize.width, thumbnailSize.height,
-				size.error);
+				size.mimeType, extension, thumbnailSize.width,
+				thumbnailSize.height, size.error);
+	}
+
+	@Nullable
+	private String getExtensionFromMimeType(String mimeType) {
+		MimeTypeMap mimeTypeMap = MimeTypeMap.getSingleton();
+		return mimeTypeMap.getExtensionFromMimeType(mimeType);
 	}
 
 	/**

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

@@ -29,7 +29,6 @@ import android.widget.ImageView;
 import android.widget.TextView;
 import android.widget.Toast;
 
-import org.briarproject.bramble.api.FormatException;
 import org.briarproject.bramble.api.Pair;
 import org.briarproject.bramble.api.contact.ContactId;
 import org.briarproject.bramble.api.contact.ContactManager;
@@ -49,7 +48,6 @@ 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;
@@ -83,7 +81,6 @@ import org.briarproject.briar.api.introduction.IntroductionManager;
 import org.briarproject.briar.api.messaging.Attachment;
 import org.briarproject.briar.api.messaging.AttachmentHeader;
 import org.briarproject.briar.api.messaging.MessagingManager;
-import org.briarproject.briar.api.messaging.PrivateMessage;
 import org.briarproject.briar.api.messaging.PrivateMessageFactory;
 import org.briarproject.briar.api.messaging.PrivateMessageHeader;
 import org.briarproject.briar.api.privategroup.invitation.GroupInvitationManager;
@@ -196,8 +193,6 @@ public class ConversationActivity extends BriarActivity
 	ViewModelProvider.Factory viewModelFactory;
 
 	private volatile ContactId contactId;
-	@Nullable
-	private volatile GroupId messagingGroupId;
 
 	private final Observer<String> contactNameObserver = name -> {
 		requireNonNull(name);
@@ -245,6 +240,8 @@ public class ConversationActivity extends BriarActivity
 			requireNonNull(deleted);
 			if (deleted) finish();
 		});
+		viewModel.getAddedPrivateMessage()
+				.observe(this, this::onAddedPrivateMessage);
 
 		setTransitionName(toolbarAvatar, getAvatarTransitionName(contactId));
 		setTransitionName(toolbarStatus, getBulbTransitionName(contactId));
@@ -397,7 +394,7 @@ public class ConversationActivity extends BriarActivity
 								textCache.put(id, text);
 							}
 						}
-						if (!h.getAttachmentHeaders().isEmpty()) {
+						if (h.getAttachmentHeaders().size() == 1) {
 							List<AttachmentItem> items =
 									attachmentController.get(id);
 							if (items == null) {
@@ -486,7 +483,7 @@ public class ConversationActivity extends BriarActivity
 			try {
 				List<Pair<AttachmentHeader, Attachment>> attachments =
 						attachmentController.getMessageAttachments(headers);
-				// TODO move getting the items off to the IoExecutor
+				// TODO move getting the items off to IoExecutor, if size == 1
 				List<AttachmentItem> items =
 						attachmentController.getAttachmentItems(attachments);
 				displayMessageAttachments(messageId, items);
@@ -600,16 +597,11 @@ public class ConversationActivity extends BriarActivity
 
 	@Override
 	public void onSendClick(@Nullable String text, List<Uri> imageUris) {
-		if (!imageUris.isEmpty()) {
-			Toast.makeText(this, "Not yet implemented.", LENGTH_LONG).show();
-			textInputView.clearText();
-			return;
-		}
-		if (isNullOrEmpty(text)) throw new AssertionError();
+		if (isNullOrEmpty(text) && imageUris.isEmpty())
+			throw new AssertionError();
 		long timestamp = System.currentTimeMillis();
 		timestamp = Math.max(timestamp, getMinTimestampForNewMessage());
-		if (messagingGroupId == null) loadGroupId(text, timestamp);
-		else createMessage(text, timestamp);
+		viewModel.sendMessage(text, imageUris, timestamp);
 		textInputView.clearText();
 	}
 
@@ -619,48 +611,10 @@ public class ConversationActivity extends BriarActivity
 		return item == null ? 0 : item.getTime() + 1;
 	}
 
-	private void loadGroupId(String text, long timestamp) {
-		runOnDbThread(() -> {
-			try {
-				messagingGroupId =
-						messagingManager.getConversationId(contactId);
-				createMessage(text, timestamp);
-			} catch (DbException e) {
-				logException(LOG, WARNING, e);
-			}
-
-		});
-	}
-
-	private void createMessage(String text, long timestamp) {
-		cryptoExecutor.execute(() -> {
-			try {
-				//noinspection ConstantConditions init in loadGroupId()
-				storeMessage(privateMessageFactory.createPrivateMessage(
-						messagingGroupId, timestamp, text, emptyList()), text);
-			} catch (FormatException e) {
-				throw new RuntimeException(e);
-			}
-		});
-	}
-
-	private void storeMessage(PrivateMessage m, String text) {
-		runOnDbThread(() -> {
-			try {
-				long start = now();
-				messagingManager.addLocalMessage(m);
-				logDuration(LOG, "Storing message", start);
-				Message message = m.getMessage();
-				PrivateMessageHeader h = new PrivateMessageHeader(
-						message.getId(), message.getGroupId(),
-						message.getTimestamp(), true, false, false, false,
-						true, emptyList());
-				textCache.put(message.getId(), text);
-				addConversationItem(h.accept(visitor));
-			} catch (DbException e) {
-				logException(LOG, WARNING, e);
-			}
-		});
+	private void onAddedPrivateMessage(@Nullable PrivateMessageHeader h) {
+		if (h == null) return;
+		addConversationItem(h.accept(visitor));
+		viewModel.onAddedPrivateMessageSeen();
 	}
 
 	private void askToRemoveContact() {

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

@@ -3,6 +3,7 @@ package org.briarproject.briar.android.conversation;
 import android.content.Context;
 import android.support.annotation.LayoutRes;
 import android.support.v7.widget.LinearLayoutManager;
+import android.support.v7.widget.RecyclerView.RecycledViewPool;
 import android.util.SparseArray;
 import android.view.LayoutInflater;
 import android.view.View;
@@ -21,11 +22,17 @@ 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
@@ -42,15 +49,17 @@ class ConversationAdapter
 				type, viewGroup, false);
 		switch (type) {
 			case R.layout.list_item_conversation_msg_in:
-				return new ConversationMessageViewHolder(v, true);
+				return new ConversationMessageViewHolder(v, listener, true,
+						imageViewPool, imageItemDecoration);
 			case R.layout.list_item_conversation_msg_out:
-				return new ConversationMessageViewHolder(v, false);
+				return new ConversationMessageViewHolder(v, listener, false,
+						imageViewPool, imageItemDecoration);
 			case R.layout.list_item_conversation_notice_in:
-				return new ConversationNoticeViewHolder(v, true);
+				return new ConversationNoticeViewHolder(v, listener, true);
 			case R.layout.list_item_conversation_notice_out:
-				return new ConversationNoticeViewHolder(v, false);
+				return new ConversationNoticeViewHolder(v, listener, false);
 			case R.layout.list_item_conversation_request:
-				return new ConversationRequestViewHolder(v, true);
+				return new ConversationRequestViewHolder(v, listener, true);
 			default:
 				throw new IllegalArgumentException("Unknown ConversationItem");
 		}
@@ -59,7 +68,7 @@ class ConversationAdapter
 	@Override
 	public void onBindViewHolder(ConversationItemViewHolder ui, int position) {
 		ConversationItem item = items.get(position);
-		ui.bind(item, listener);
+		ui.bind(item);
 		listener.onItemVisible(item);
 	}
 

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

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

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

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

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

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

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

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

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

@@ -5,19 +5,36 @@ 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.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.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.List;
 import java.util.concurrent.Executor;
 import java.util.logging.Logger;
 
@@ -26,9 +43,11 @@ 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.util.UiUtils.observeForeverOnce;
 
 @NotNullByDefault
 public class ConversationViewModel extends AndroidViewModel {
@@ -38,7 +57,11 @@ public class ConversationViewModel extends AndroidViewModel {
 
 	@DatabaseExecutor
 	private final Executor dbExecutor;
+	@CryptoExecutor
+	private final Executor cryptoExecutor;
+	private final MessagingManager messagingManager;
 	private final ContactManager contactManager;
+	private final PrivateMessageFactory privateMessageFactory;
 	private final AttachmentController attachmentController;
 
 	@Nullable
@@ -50,14 +73,24 @@ public class ConversationViewModel extends AndroidViewModel {
 			Transformations.map(contact, UiUtils::getContactDisplayName);
 	private final MutableLiveData<Boolean> contactDeleted =
 			new MutableLiveData<>();
+	private final MutableLiveData<GroupId> messagingGroupId =
+			new MutableLiveData<>();
+	private final MutableLiveData<PrivateMessageHeader> addedHeader =
+			new MutableLiveData<>();
 
 	@Inject
 	ConversationViewModel(Application application,
 			@DatabaseExecutor Executor dbExecutor,
-			ContactManager contactManager, MessagingManager messagingManager) {
+			@CryptoExecutor Executor cryptoExecutor,
+			MessagingManager messagingManager,
+			ContactManager contactManager,
+			PrivateMessageFactory privateMessageFactory) {
 		super(application);
 		this.dbExecutor = dbExecutor;
+		this.cryptoExecutor = cryptoExecutor;
+		this.messagingManager = messagingManager;
 		this.contactManager = contactManager;
+		this.privateMessageFactory = privateMessageFactory;
 		this.attachmentController = new AttachmentController(messagingManager,
 				application.getResources());
 		contactDeleted.setValue(false);
@@ -100,6 +133,119 @@ public class ConversationViewModel extends AndroidViewModel {
 		});
 	}
 
+	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);
+			}
+		});
+	}
+
+	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;
 	}
@@ -120,4 +266,8 @@ public class ConversationViewModel extends AndroidViewModel {
 		return contactDeleted;
 	}
 
+	LiveData<PrivateMessageHeader> getAddedPrivateMessage() {
+		return addedHeader;
+	}
+
 }

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

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

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

@@ -0,0 +1,54 @@
+package org.briarproject.briar.android.conversation;
+
+import android.content.Context;
+import android.content.res.Resources;
+import android.graphics.Rect;
+import android.support.v7.widget.RecyclerView;
+import android.support.v7.widget.RecyclerView.ItemDecoration;
+import android.support.v7.widget.RecyclerView.State;
+import android.view.View;
+
+import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
+import org.briarproject.briar.R;
+import org.briarproject.briar.android.util.UiUtils;
+
+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;
+
+@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 = UiUtils.isRtl(ctx);
+	}
+
+	@Override
+	public void getItemOffsets(Rect outRect, View view, RecyclerView parent,
+			State state) {
+		if (state.getItemCount() == 1) return;
+		int pos = parent.getChildAdapterPosition(view);
+		int num = state.getItemCount();
+		boolean start = isLeft(pos) ^ isRtl;
+		outRect.top = isTopRow(pos) ? 0 : border;
+		outRect.left = start ? 0 : border;
+		outRect.right = start && !singleInRow(pos, num) ? border : 0;
+		outRect.bottom = isBottomRow(pos, num) ? 0 : border;
+	}
+
+}

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

@@ -0,0 +1,70 @@
+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 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);
+		}
+	}
+
+	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

@@ -48,10 +48,10 @@ public class ImageViewModel extends AndroidViewModel {
 	@IoExecutor
 	private final Executor ioExecutor;
 
-	private MutableLiveData<Boolean> saveState = new MutableLiveData<>();
+	private final MutableLiveData<Boolean> saveState = new MutableLiveData<>();
 
 	@Inject
-	public ImageViewModel(Application application,
+	ImageViewModel(Application application,
 			MessagingManager messagingManager,
 			@DatabaseExecutor Executor dbExecutor,
 			@IoExecutor Executor ioExecutor) {

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

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

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

@@ -0,0 +1,128 @@
+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
+public class CustomCornersTransformation extends BitmapTransformation {
+
+	private static final String ID = CustomCornersTransformation.class.getName();
+
+	private final Radii radii;
+
+	public CustomCornersTransformation(Radii radii) {
+		this.radii = radii;
+	}
+
+	@Override
+	protected Bitmap transform(BitmapPool pool, Bitmap toTransform,
+			int outWidth, int outHeight) {
+		int width = toTransform.getWidth();
+		int height = toTransform.getHeight();
+
+		Bitmap bitmap = pool.get(width, height, ARGB_8888);
+		bitmap.setHasAlpha(true);
+
+		Canvas canvas = new Canvas(bitmap);
+		Paint paint = new Paint();
+		paint.setAntiAlias(true);
+		paint.setShader(new BitmapShader(toTransform, CLAMP, CLAMP));
+		drawRect(canvas, paint, width, height);
+		return bitmap;
+	}
+
+	private void drawRect(Canvas canvas, Paint paint, float width,
+			float height) {
+		drawTopLeft(canvas, paint, radii.topLeft, width, height);
+		drawTopRight(canvas, paint, radii.topRight, width, height);
+		drawBottomLeft(canvas, paint, radii.bottomLeft, width, height);
+		drawBottomRight(canvas, paint, radii.bottomRight, width, height);
+	}
+
+	private void drawTopLeft(Canvas canvas, Paint paint, int radius,
+			float width, float height) {
+		RectF rect = new RectF(
+				0,
+				0,
+				width / 2 + radius + 1,
+				height / 2 + radius + 1
+		);
+		if (radius == 0) canvas.drawRect(rect, paint);
+		else canvas.drawRoundRect(rect, radius, radius, paint);
+	}
+
+	private void drawTopRight(Canvas canvas, Paint paint, int radius,
+			float width, float height) {
+		RectF rect = new RectF(
+				width / 2 - radius,
+				0,
+				width,
+				height / 2 + radius + 1
+		);
+		if (radius == 0) canvas.drawRect(rect, paint);
+		else canvas.drawRoundRect(rect, radius, radius, paint);
+	}
+
+	private void drawBottomLeft(Canvas canvas, Paint paint, int radius,
+			float width, float height) {
+		RectF rect = new RectF(
+				0,
+				height / 2 - radius,
+				width / 2 + radius + 1,
+				height
+		);
+		if (radius == 0) canvas.drawRect(rect, paint);
+		else canvas.drawRoundRect(rect, radius, radius, paint);
+	}
+
+	private void drawBottomRight(Canvas canvas, Paint paint, int radius,
+			float width, float height) {
+		RectF rect = new RectF(
+				width / 2 - radius,
+				height / 2 - radius,
+				width,
+				height
+		);
+		if (radius == 0) canvas.drawRect(rect, paint);
+		else canvas.drawRoundRect(rect, radius, radius, paint);
+	}
+
+	@Override
+	public String toString() {
+		return "ImageCornerTransformation(" + radii + ")";
+	}
+
+	@Override
+	public boolean equals(Object o) {
+		return o instanceof CustomCornersTransformation &&
+				radii.equals(((CustomCornersTransformation) o).radii);
+	}
+
+	@Override
+	public int hashCode() {
+		return ID.hashCode() + radii.hashCode();
+	}
+
+	@Override
+	public void updateDiskCacheKey(@NonNull MessageDigest messageDigest) {
+		messageDigest.update((ID + radii).getBytes(CHARSET));
+	}
+
+}

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

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

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

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

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

@@ -14,9 +14,9 @@ import android.os.PowerManager;
 import android.support.annotation.AttrRes;
 import android.support.annotation.ColorInt;
 import android.support.annotation.ColorRes;
-import android.support.annotation.MainThread;
 import android.support.annotation.Nullable;
 import android.support.annotation.RequiresApi;
+import android.support.annotation.UiThread;
 import android.support.design.widget.TextInputLayout;
 import android.support.v4.app.FragmentManager;
 import android.support.v4.content.ContextCompat;
@@ -56,6 +56,7 @@ import static android.content.Intent.FLAG_ACTIVITY_NEW_TASK;
 import static android.os.Build.MANUFACTURER;
 import static android.os.Build.VERSION.SDK_INT;
 import static android.provider.Settings.ACTION_REQUEST_IGNORE_BATTERY_OPTIMIZATIONS;
+import static android.support.v4.view.ViewCompat.LAYOUT_DIRECTION_RTL;
 import static android.support.v7.app.AppCompatDelegate.MODE_NIGHT_AUTO;
 import static android.support.v7.app.AppCompatDelegate.MODE_NIGHT_FOLLOW_SYSTEM;
 import static android.support.v7.app.AppCompatDelegate.MODE_NIGHT_NO;
@@ -342,7 +343,7 @@ public class UiUtils {
 	 * If the LiveData's value is available, the {@link Observer} will be
 	 * called right away.
 	 */
-	@MainThread
+	@UiThread
 	public static <T> void observeOnce(LiveData<T> liveData,
 			LifecycleOwner owner, Observer<T> observer) {
 		liveData.observe(owner, new Observer<T>() {
@@ -354,4 +355,28 @@ public class UiUtils {
 		});
 	}
 
+	/**
+	 * Same as {@link #observeOnce(LiveData, LifecycleOwner, Observer)},
+	 * but without a {@link LifecycleOwner}.
+	 *
+	 * Warning: Do NOT call from objects that have a lifecycle.
+	 */
+	@UiThread
+	public static <T> void observeForeverOnce(LiveData<T> liveData,
+			Observer<T> observer) {
+		liveData.observeForever(new Observer<T>() {
+			@Override
+			public void onChanged(@Nullable T t) {
+				observer.onChanged(t);
+				liveData.removeObserver(this);
+			}
+		});
+	}
+
+	public static boolean isRtl(Context ctx) {
+		if (SDK_INT < 17) return false;
+		return ctx.getResources().getConfiguration().getLayoutDirection() ==
+				LAYOUT_DIRECTION_RTL;
+	}
+
 }

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

@@ -15,15 +15,19 @@
 	android:background="@drawable/msg_in"
 	android:elevation="@dimen/message_bubble_elevation">
 
-	<ImageView
-		android:id="@+id/imageView"
+	<android.support.v7.widget.RecyclerView
+		android:id="@+id/imageList"
 		android:layout_width="@dimen/message_bubble_image_default"
 		android:layout_height="@dimen/message_bubble_image_default"
+		android:orientation="vertical"
+		app:layoutManager="android.support.v7.widget.StaggeredGridLayoutManager"
 		app:layout_constraintBottom_toTopOf="@+id/text"
+		app:layout_constraintEnd_toEndOf="parent"
 		app:layout_constraintStart_toStartOf="parent"
 		app:layout_constraintTop_toTopOf="parent"
+		app:spanCount="2"
 		tools:ignore="ContentDescription"
-		tools:src="@drawable/alerts_and_states_error"/>
+		tools:listitem="@layout/list_item_image"/>
 
 	<com.vanniktech.emoji.EmojiTextView
 		android:id="@+id/text"
@@ -38,10 +42,10 @@
 		android:visibility="gone"
 		app:layout_constrainedWidth="true"
 		app:layout_constraintBottom_toTopOf="@+id/statusLayout"
-		app:layout_constraintEnd_toEndOf="@+id/imageView"
+		app:layout_constraintEnd_toEndOf="@+id/imageList"
 		app:layout_constraintHorizontal_bias="0.0"
 		app:layout_constraintStart_toStartOf="parent"
-		app:layout_constraintTop_toBottomOf="@+id/imageView"
+		app:layout_constraintTop_toBottomOf="@+id/imageList"
 		tools:text="The text of a message which can sometimes be a bit longer as well"/>
 
 	<LinearLayout
@@ -53,7 +57,7 @@
 		android:layout_marginRight="@dimen/message_bubble_padding_sides_inner"
 		android:background="@drawable/msg_status_bubble"
 		android:orientation="horizontal"
-		app:layout_constraintBottom_toBottomOf="@+id/imageView"
+		app:layout_constraintBottom_toBottomOf="@+id/imageList"
 		app:layout_constraintEnd_toEndOf="parent"
 		app:layout_constraintHorizontal_bias="1.0"
 		app:layout_constraintStart_toStartOf="parent">

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

@@ -15,15 +15,19 @@
 	android:background="@drawable/msg_in"
 	android:elevation="@dimen/message_bubble_elevation">
 
-	<ImageView
-		android:id="@+id/imageView"
+	<android.support.v7.widget.RecyclerView
+		android:id="@+id/imageList"
 		android:layout_width="@dimen/message_bubble_image_default"
 		android:layout_height="@dimen/message_bubble_image_default"
+		android:orientation="vertical"
+		app:layoutManager="android.support.v7.widget.StaggeredGridLayoutManager"
 		app:layout_constraintBottom_toTopOf="@+id/text"
+		app:layout_constraintEnd_toEndOf="parent"
 		app:layout_constraintStart_toStartOf="parent"
 		app:layout_constraintTop_toTopOf="parent"
+		app:spanCount="2"
 		tools:ignore="ContentDescription"
-		tools:src="@drawable/alerts_and_states_error"/>
+		tools:listitem="@layout/list_item_image"/>
 
 	<com.vanniktech.emoji.EmojiTextView
 		android:id="@+id/text"
@@ -37,10 +41,10 @@
 		android:textColor="?android:attr/textColorPrimary"
 		app:layout_constrainedWidth="true"
 		app:layout_constraintBottom_toTopOf="@+id/statusLayout"
-		app:layout_constraintEnd_toEndOf="@+id/imageView"
+		app:layout_constraintEnd_toEndOf="@+id/imageList"
 		app:layout_constraintHorizontal_bias="0.0"
 		app:layout_constraintStart_toStartOf="parent"
-		app:layout_constraintTop_toBottomOf="@+id/imageView"
+		app:layout_constraintTop_toBottomOf="@+id/imageList"
 		tools:text="The text of a message which can sometimes be a bit longer as well"/>
 
 	<LinearLayout

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

@@ -15,15 +15,20 @@
 	android:background="@drawable/msg_in"
 	android:elevation="@dimen/message_bubble_elevation">
 
-	<ImageView
-		android:id="@+id/imageView"
+	<android.support.v7.widget.RecyclerView
+		android:id="@+id/imageList"
 		android:layout_width="@dimen/message_bubble_image_default"
 		android:layout_height="@dimen/message_bubble_image_default"
+		android:orientation="vertical"
 		android:visibility="gone"
+		app:layoutManager="android.support.v7.widget.StaggeredGridLayoutManager"
 		app:layout_constraintBottom_toTopOf="@+id/text"
+		app:layout_constraintEnd_toEndOf="parent"
 		app:layout_constraintStart_toStartOf="parent"
 		app:layout_constraintTop_toTopOf="parent"
-		tools:ignore="ContentDescription"/>
+		app:spanCount="2"
+		tools:ignore="ContentDescription"
+		tools:listitem="@layout/list_item_image"/>
 
 	<com.vanniktech.emoji.EmojiTextView
 		android:id="@+id/text"
@@ -40,7 +45,7 @@
 		app:layout_constraintEnd_toEndOf="parent"
 		app:layout_constraintHorizontal_bias="0.0"
 		app:layout_constraintStart_toStartOf="parent"
-		app:layout_constraintTop_toBottomOf="@+id/imageView"
+		app:layout_constraintTop_toBottomOf="@+id/imageList"
 		tools:text="The text of a message which can sometimes be a bit longer as well"/>
 
 	<LinearLayout

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

@@ -21,14 +21,18 @@
 		android:background="@drawable/msg_out"
 		android:elevation="@dimen/message_bubble_elevation">
 
-		<ImageView
-			android:id="@+id/imageView"
+		<android.support.v7.widget.RecyclerView
+			android:id="@+id/imageList"
 			android:layout_width="@dimen/message_bubble_image_default"
 			android:layout_height="@dimen/message_bubble_image_default"
+			android:orientation="vertical"
 			android:visibility="gone"
+			app:layoutManager="android.support.v7.widget.StaggeredGridLayoutManager"
 			app:layout_constraintBottom_toTopOf="@+id/text"
+			app:layout_constraintEnd_toEndOf="parent"
 			app:layout_constraintStart_toStartOf="parent"
 			app:layout_constraintTop_toTopOf="parent"
+			app:spanCount="2"
 			tools:ignore="ContentDescription"
 			tools:src="@drawable/alerts_and_states_error"/>
 
@@ -47,7 +51,7 @@
 			app:layout_constraintEnd_toEndOf="parent"
 			app:layout_constraintHorizontal_bias="0.0"
 			app:layout_constraintStart_toStartOf="parent"
-			app:layout_constraintTop_toBottomOf="@+id/imageView"
+			app:layout_constraintTop_toBottomOf="@+id/imageList"
 			tools:text="This is a long long long message that spans over several lines.\n\nIt ends here."/>
 
 		<LinearLayout

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

@@ -0,0 +1,10 @@
+<?xml version="1.0" encoding="utf-8"?>
+<ImageView
+	android:id="@+id/imageView"
+	xmlns:android="http://schemas.android.com/apk/res/android"
+	xmlns:tools="http://schemas.android.com/tools"
+	android:layout_width="@dimen/message_bubble_image_default"
+	android:layout_height="@dimen/message_bubble_image_default"
+	android:scaleType="centerCrop"
+	tools:ignore="ContentDescription"
+	tools:srcCompat="@tools:sample/avatars"/>

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

@@ -43,7 +43,7 @@
 	<dimen name="message_bubble_radius_top_inner">@dimen/message_bubble_radius_small</dimen>
 	<dimen name="message_bubble_radius_top_outer">@dimen/message_bubble_radius_big</dimen>
 	<dimen name="message_bubble_margin">6dp</dimen>
-	<dimen name="message_bubble_image_default">210dp</dimen>
+	<dimen name="message_bubble_image_default">115dp</dimen>
 	<dimen name="message_bubble_image_min_width">150dp</dimen>
 	<dimen name="message_bubble_image_max_width">240dp</dimen>
 	<dimen name="message_bubble_image_min_height">100dp</dimen>

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

@@ -8,7 +8,8 @@ import org.briarproject.bramble.api.sync.GroupId;
 import org.briarproject.bramble.api.sync.MessageId;
 import org.briarproject.briar.api.conversation.ConversationManager.ConversationClient;
 
-import java.nio.ByteBuffer;
+import java.io.IOException;
+import java.io.InputStream;
 
 @NotNullByDefault
 public interface MessagingManager extends ConversationClient {
@@ -37,7 +38,7 @@ public interface MessagingManager extends ConversationClient {
 	 * Stores a local attachment message.
 	 */
 	AttachmentHeader addLocalAttachment(GroupId groupId, long timestamp,
-			String contentType, ByteBuffer data) throws DbException;
+			String contentType, InputStream is) throws DbException, IOException;
 
 	/**
 	 * Returns the ID of the contact with the given private conversation.

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

@@ -32,9 +32,11 @@ import org.briarproject.briar.api.messaging.PrivateMessageHeader;
 import org.briarproject.briar.api.messaging.event.PrivateMessageReceivedEvent;
 import org.briarproject.briar.client.ConversationClientImpl;
 
-import java.nio.ByteBuffer;
+import java.io.IOException;
+import java.io.InputStream;
 import java.util.ArrayList;
 import java.util.Collection;
+import java.util.List;
 import java.util.Map;
 import java.util.Random;
 
@@ -42,6 +44,7 @@ import javax.annotation.concurrent.Immutable;
 import javax.inject.Inject;
 
 import static java.util.Collections.emptyList;
+import static java.util.logging.Logger.getLogger;
 import static org.briarproject.briar.client.MessageTrackerConstants.MSG_KEY_READ;
 
 @Immutable
@@ -152,8 +155,9 @@ class MessagingManagerImpl extends ConversationClientImpl
 
 	@Override
 	public AttachmentHeader addLocalAttachment(GroupId groupId, long timestamp,
-			String contentType, ByteBuffer data) {
+			String contentType, InputStream is) throws IOException {
 		// TODO add real implementation
+		if (is.available() == 0) throw new IOException();
 		byte[] b = new byte[MessageId.LENGTH];
 		new Random().nextBytes(b);
 		return new AttachmentHeader(new MessageId(b), "image/png");
@@ -215,8 +219,18 @@ class MessagingManagerImpl extends ConversationClientImpl
 				long timestamp = meta.getLong("timestamp");
 				boolean local = meta.getBoolean("local");
 				boolean read = meta.getBoolean("read");
+				// TODO replace fake attachments by real ones
+				int num = (int) (timestamp % 5);
+				boolean hasText = num == 0 || id.hashCode() % 2 == 0;
+				List<AttachmentHeader> attachments = new ArrayList<>(num);
+				for (int i = 0; i < num; i++) {
+					byte[] aIdBytes = id.getBytes().clone();
+					aIdBytes[0] = (byte) i;
+					MessageId aId = new MessageId(aIdBytes);
+					attachments.add(new AttachmentHeader(aId, "image/jpeg"));
+				}
 				headers.add(new PrivateMessageHeader(id, g, timestamp, local,
-						read, s.isSent(), s.isSeen(), true, emptyList()));
+						read, s.isSent(), s.isSeen(), hasText, attachments));
 			} catch (FormatException e) {
 				throw new DbException(e);
 			}
@@ -237,7 +251,30 @@ class MessagingManagerImpl extends ConversationClientImpl
 	@Override
 	public Attachment getAttachment(MessageId m) {
 		// TODO add real implementation
-		throw new IllegalStateException("Not yet implemented");
+		String[] files = new String[] {
+//				"error_animated.gif",
+//				"error_high.jpg",
+//				"error_wide.jpg",
+//				"error_huge.gif",
+//				"error_large.gif",
+//				"error_malformed.jpg",
+//				"wide.jpg",
+//				"high.jpg",
+//				"small.png",
+				"kitten1.jpg",
+				"kitten2.jpg",
+				"kitten3.gif",
+				"kitten4.jpg",
+				"kitten5.jpg",
+				"kitten6.png",
+		};
+		int index = Math.abs(m.hashCode() % files.length);
+		String file = files[index];
+		getLogger(MessagingManagerImpl.class.getName())
+				.warning("Loading file: " + file);
+
+		InputStream is = getClass().getClassLoader().getResourceAsStream(file);
+		return new Attachment(is);
 	}
 
 }