Remove observer when load completes or is cancelled.

Allow forums to be removed without opening them

See merge request briar/briar!1841

bramble-core/src/main/java/org/briarproject/bramble/db/H2Database.java

@@ -89,11 +89,17 @@ class H2Database extends JdbcDatabase {
 		try {
 			c = createConnection();
 			closeAllConnections();
-			setDirty(c, false);
+			LOG.info("Compacting DB");
 			s = c.createStatement();
 			s.execute("SHUTDOWN COMPACT");
+			LOG.info("Finished compacting DB");
 			s.close();
 			c.close();
+			// Reopen the DB to mark it as clean after compacting
+			c = createConnection();
+			setDirty(c, false);
+			LOG.info("Marked DB as clean");
+			c.close();
 		} catch (SQLException e) {
 			tryToClose(s, LOG, WARNING);
 			tryToClose(c, LOG, WARNING);
@@ -126,6 +132,7 @@ class H2Database extends JdbcDatabase {
 			closeAllConnections();
 			s = c.createStatement();
 			s.execute("SHUTDOWN COMPACT");
+			LOG.info("Finished compacting DB");
 			s.close();
 			c.close();
 		} catch (SQLException e) {

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

@@ -217,19 +217,14 @@ public class BriarService extends Service {
 
 	@Override
 	public void onDestroy() {
-		// Hold a wake lock during shutdown
-		wakeLockManager.runWakefully(() -> {
-			super.onDestroy();
-			LOG.info("Destroyed");
-			stopForeground(true);
-			if (receiver != null) {
-				getApplicationContext().unregisterReceiver(receiver);
-			}
-			// Stop the services in a background thread
-			wakeLockManager.executeWakefully(() -> {
-				if (started) lifecycleManager.stopServices();
-			}, "LifecycleShutdown");
-		}, "LifecycleShutdown");
+		super.onDestroy();
+		LOG.info("Destroyed");
+		// Stop the lifecycle, if not already stopped
+		shutdown(false);
+		stopForeground(true);
+		if (receiver != null) {
+			getApplicationContext().unregisterReceiver(receiver);
+		}
 	}
 
 	@Override
@@ -299,8 +294,8 @@ public class BriarService extends Service {
 	private void shutdownFromBackground() {
 		// Hold a wake lock during shutdown
 		wakeLockManager.runWakefully(() -> {
-			// Stop the service
-			stopSelf();
+			// Begin lifecycle shutdown
+			shutdown(true);
 			// Hide the UI
 			hideUi();
 			// Wait for shutdown to complete, then exit
@@ -335,8 +330,18 @@ public class BriarService extends Service {
 	/**
 	 * Starts the shutdown process.
 	 */
-	public void shutdown() {
-		stopSelf(); // This will call onDestroy()
+	public void shutdown(boolean stopAndroidService) {
+		// Hold a wake lock during shutdown
+		wakeLockManager.runWakefully(() -> {
+			// Stop the lifecycle services in a background thread,
+			// then stop this Android service if needed
+			wakeLockManager.executeWakefully(() -> {
+				if (started) lifecycleManager.stopServices();
+				if (stopAndroidService) {
+					androidExecutor.runOnUiThread(() -> stopSelf());
+				}
+			}, "LifecycleShutdown");
+		}, "LifecycleShutdown");
 	}
 
 	public class BriarBinder extends Binder {

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

@@ -147,7 +147,7 @@ public class BriarControllerImpl implements BriarController {
 				service.waitForStartup();
 				// Shut down the service and wait for it to shut down
 				LOG.info("Shutting down service");
-				service.shutdown();
+				service.shutdown(true);
 				service.waitForShutdown();
 			} catch (InterruptedException e) {
 				LOG.warning("Interrupted while waiting for service");

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

@@ -54,7 +54,7 @@ public class ForumActivity extends
 
 	@Override
 	protected ThreadItemAdapter<ForumPostItem> createAdapter() {
-		return new ThreadItemAdapter<>(this);
+		return new ThreadItemAdapter<>(this, this);
 	}
 
 	@Override

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

@@ -13,15 +13,18 @@ import androidx.recyclerview.widget.ListAdapter;
 @NotNullByDefault
 class ForumListAdapter extends ListAdapter<ForumListItem, ForumViewHolder> {
 
-	ForumListAdapter() {
+	private final ForumListViewModel viewModel;
+
+	ForumListAdapter(ForumListViewModel viewModel) {
 		super(new ForumListCallback());
+		this.viewModel = viewModel;
 	}
 
 	@Override
 	public ForumViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
 		View v = LayoutInflater.from(parent.getContext()).inflate(
 				R.layout.list_item_forum, parent, false);
-		return new ForumViewHolder(v);
+		return new ForumViewHolder(v, viewModel);
 	}
 
 	@Override

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

@@ -40,7 +40,7 @@ public class ForumListFragment extends BaseFragment implements
 	private ForumListViewModel viewModel;
 	private BriarRecyclerView list;
 	private Snackbar snackbar;
-	private final ForumListAdapter adapter = new ForumListAdapter();
+	private ForumListAdapter adapter;
 
 	@Inject
 	ViewModelProvider.Factory viewModelFactory;
@@ -54,6 +54,7 @@ public class ForumListFragment extends BaseFragment implements
 		component.inject(this);
 		viewModel = new ViewModelProvider(this, viewModelFactory)
 				.get(ForumListViewModel.class);
+		adapter = new ForumListAdapter(viewModel);
 	}
 
 	@Nullable

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

@@ -1,6 +1,7 @@
 package org.briarproject.briar.android.forum;
 
 import android.app.Application;
+import android.widget.Toast;
 
 import org.briarproject.bramble.api.contact.event.ContactRemovedEvent;
 import org.briarproject.bramble.api.db.DatabaseExecutor;
@@ -15,6 +16,7 @@ import org.briarproject.bramble.api.sync.GroupId;
 import org.briarproject.bramble.api.sync.event.GroupAddedEvent;
 import org.briarproject.bramble.api.sync.event.GroupRemovedEvent;
 import org.briarproject.bramble.api.system.AndroidExecutor;
+import org.briarproject.briar.R;
 import org.briarproject.briar.android.viewmodel.DbViewModel;
 import org.briarproject.briar.android.viewmodel.LiveResult;
 import org.briarproject.briar.api.android.AndroidNotificationManager;
@@ -40,6 +42,7 @@ import androidx.annotation.UiThread;
 import androidx.lifecycle.LiveData;
 import androidx.lifecycle.MutableLiveData;
 
+import static android.widget.Toast.LENGTH_SHORT;
 import static java.util.logging.Logger.getLogger;
 import static org.briarproject.bramble.util.LogUtils.logDuration;
 import static org.briarproject.bramble.util.LogUtils.now;
@@ -180,4 +183,17 @@ class ForumListViewModel extends DbViewModel implements EventListener {
 		return numInvitations;
 	}
 
+	void deleteForum(GroupId groupId) {
+		runOnDbThread(() -> {
+			try {
+				Forum f = forumManager.getForum(groupId);
+				forumManager.removeForum(f);
+				androidExecutor.runOnUiThread(() -> Toast
+						.makeText(getApplication(), R.string.forum_left_toast,
+								LENGTH_SHORT).show());
+			} catch (DbException e) {
+				handleException(e);
+			}
+		});
+	}
 }

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

@@ -6,10 +6,10 @@ import org.briarproject.briar.api.forum.ForumPostHeader;
 import javax.annotation.concurrent.NotThreadSafe;
 
 @NotThreadSafe
-class ForumPostItem extends ThreadItem {
+public class ForumPostItem extends ThreadItem {
 
-	ForumPostItem(ForumPostHeader h, String text) {
-		super(h.getId(), h.getParentId(), text, h.getTimestamp(), h.getAuthor(),
+	ForumPostItem(ForumPostHeader h) {
+		super(h.getId(), h.getParentId(), h.getTimestamp(), h.getAuthor(),
 				h.getAuthorInfo(), h.isRead());
 	}
 

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

@@ -4,6 +4,7 @@ import android.content.Context;
 import android.content.Intent;
 import android.view.View;
 import android.view.ViewGroup;
+import android.widget.PopupMenu;
 import android.widget.TextView;
 
 import org.briarproject.briar.R;
@@ -20,6 +21,7 @@ import static org.briarproject.briar.android.activity.BriarActivity.GROUP_NAME;
 
 class ForumViewHolder extends RecyclerView.ViewHolder {
 
+	private final ForumListViewModel viewModel;
 	private final Context ctx;
 	private final ViewGroup layout;
 	private final TextAvatarView avatar;
@@ -27,8 +29,9 @@ class ForumViewHolder extends RecyclerView.ViewHolder {
 	private final TextView postCount;
 	private final TextView date;
 
-	ForumViewHolder(View v) {
+	ForumViewHolder(View v, ForumListViewModel viewModel) {
 		super(v);
+		this.viewModel = viewModel;
 		ctx = v.getContext();
 		layout = (ViewGroup) v;
 		avatar = v.findViewById(R.id.avatarView);
@@ -64,6 +67,21 @@ class ForumViewHolder extends RecyclerView.ViewHolder {
 			date.setVisibility(VISIBLE);
 		}
 
+		// Open popup menu on long click
+		layout.setOnLongClickListener(v -> {
+			PopupMenu pm = new PopupMenu(ctx, v);
+			pm.getMenuInflater().inflate(R.menu.forum_list_item_actions,
+					pm.getMenu());
+			pm.setOnMenuItemClickListener(it -> {
+				if (it.getItemId() == R.id.action_forum_delete) {
+					viewModel.deleteForum(item.getForum().getId());
+				}
+				return true;
+			});
+			pm.show();
+			return true;
+		});
+
 		// Open Forum on Click
 		layout.setOnClickListener(v -> {
 			Intent i = new Intent(ctx, ForumActivity.class);

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

@@ -91,9 +91,7 @@ class ForumViewModel extends ThreadListViewModel<ForumPostItem> {
 			ForumPostReceivedEvent f = (ForumPostReceivedEvent) e;
 			if (f.getGroupId().equals(groupId)) {
 				LOG.info("Forum post received, adding...");
-				ForumPostItem item =
-						new ForumPostItem(f.getHeader(), f.getText());
-				addItem(item, false);
+				addItem(new ForumPostItem(f.getHeader()), false);
 			}
 		} else if (e instanceof ForumInvitationResponseReceivedEvent) {
 			ForumInvitationResponseReceivedEvent f =
@@ -139,22 +137,14 @@ class ForumViewModel extends ThreadListViewModel<ForumPostItem> {
 			List<ForumPostHeader> headers =
 					forumManager.getPostHeaders(txn, groupId);
 			logDuration(LOG, "Loading headers", start);
-			start = now();
 			List<ForumPostItem> items = new ArrayList<>();
 			for (ForumPostHeader header : headers) {
-				items.add(loadItem(txn, header));
+				items.add(new ForumPostItem(header));
 			}
-			logDuration(LOG, "Loading bodies and creating items", start);
 			return items;
 		}, this::setItems);
 	}
 
-	private ForumPostItem loadItem(Transaction txn, ForumPostHeader header)
-			throws DbException {
-		String text = forumManager.getPostText(txn, header.getId());
-		return new ForumPostItem(header, text);
-	}
-
 	@Override
 	public void createAndStoreMessage(String text,
 			@Nullable MessageId parentId) {
@@ -175,21 +165,17 @@ class ForumViewModel extends ThreadListViewModel<ForumPostItem> {
 			@Nullable MessageId parentId, LocalAuthor author) {
 		cryptoExecutor.execute(() -> {
 			LOG.info("Creating forum post...");
-			ForumPost msg = forumManager.createLocalPost(groupId, text,
-					timestamp, parentId, author);
-			storePost(msg, text);
+			storePost(forumManager.createLocalPost(groupId, text,
+					timestamp, parentId, author));
 		});
 	}
 
-	private void storePost(ForumPost msg, String text) {
+	private void storePost(ForumPost msg) {
 		runOnDbThread(false, txn -> {
 			long start = now();
 			ForumPostHeader header = forumManager.addLocalPost(txn, msg);
 			logDuration(LOG, "Storing forum post", start);
-			txn.attach(() -> {
-				ForumPostItem item = new ForumPostItem(header, text);
-				addItem(item, true);
-			});
+			txn.attach(() -> addItem(new ForumPostItem(header), true));
 		}, this::handleException);
 	}
 
@@ -229,4 +215,9 @@ class ForumViewModel extends ThreadListViewModel<ForumPostItem> {
 		});
 	}
 
+	@Override
+	protected String getMessageText(Transaction txn, MessageId m)
+			throws DbException {
+		return forumManager.getPostText(txn, m);
+	}
 }

briar-android/src/main/java/org/briarproject/briar/android/privategroup/conversation/GroupActivity.java

@@ -15,7 +15,6 @@ import org.briarproject.briar.android.privategroup.memberlist.GroupMemberListAct
 import org.briarproject.briar.android.privategroup.reveal.RevealContactsActivity;
 import org.briarproject.briar.android.threaded.ThreadListActivity;
 import org.briarproject.briar.android.threaded.ThreadListViewModel;
-import org.briarproject.briar.android.widget.LinkDialogFragment;
 import org.briarproject.nullsafety.MethodsNotNullByDefault;
 import org.briarproject.nullsafety.ParametersNotNullByDefault;
 
@@ -56,7 +55,7 @@ public class GroupActivity extends
 
 	@Override
 	protected GroupMessageAdapter createAdapter() {
-		return new GroupMessageAdapter(this);
+		return new GroupMessageAdapter(this, this);
 	}
 
 	@Override
@@ -160,12 +159,6 @@ public class GroupActivity extends
 		if (isDissolved != null && !isDissolved) super.onReplyClick(item);
 	}
 
-	@Override
-	public void onLinkClick(String url){
-		LinkDialogFragment f = LinkDialogFragment.newInstance(url);
-		f.show(getSupportFragmentManager(), f.getUniqueTag());
-	}
-
 	private void setGroupEnabled(boolean enabled) {
 		sendController.setReady(enabled);
 		list.getRecyclerView().setAlpha(enabled ? 1f : 0.5f);

briar-android/src/main/java/org/briarproject/briar/android/privategroup/conversation/GroupMessageAdapter.java

@@ -11,16 +11,19 @@ import org.briarproject.briar.android.threaded.ThreadPostViewHolder;
 import org.briarproject.nullsafety.NotNullByDefault;
 
 import androidx.annotation.LayoutRes;
+import androidx.annotation.NonNull;
 import androidx.annotation.UiThread;
+import androidx.lifecycle.LifecycleOwner;
 
 @UiThread
 @NotNullByDefault
-class GroupMessageAdapter extends ThreadItemAdapter<GroupMessageItem> {
+public class GroupMessageAdapter extends ThreadItemAdapter<GroupMessageItem> {
 
 	private boolean isCreator = false;
 
-	GroupMessageAdapter(ThreadItemListener<GroupMessageItem> listener) {
-		super(listener);
+	GroupMessageAdapter(LifecycleOwner lifecycleOwner,
+			ThreadItemListener<GroupMessageItem> listener) {
+		super(lifecycleOwner, listener);
 	}
 
 	@LayoutRes
@@ -30,6 +33,7 @@ class GroupMessageAdapter extends ThreadItemAdapter<GroupMessageItem> {
 		return item.getLayout();
 	}
 
+	@NonNull
 	@Override
 	public BaseThreadItemViewHolder<GroupMessageItem> onCreateViewHolder(
 			ViewGroup parent, int type) {

briar-android/src/main/java/org/briarproject/briar/android/privategroup/conversation/GroupMessageItem.java

@@ -1,14 +1,10 @@
 package org.briarproject.briar.android.privategroup.conversation;
 
-import org.briarproject.bramble.api.identity.Author;
-import org.briarproject.briar.api.identity.AuthorInfo;
 import org.briarproject.bramble.api.sync.GroupId;
-import org.briarproject.bramble.api.sync.MessageId;
 import org.briarproject.briar.R;
 import org.briarproject.briar.android.threaded.ThreadItem;
 import org.briarproject.briar.api.privategroup.GroupMessageHeader;
 
-import javax.annotation.Nullable;
 import javax.annotation.concurrent.NotThreadSafe;
 
 import androidx.annotation.LayoutRes;
@@ -16,20 +12,14 @@ import androidx.annotation.UiThread;
 
 @UiThread
 @NotThreadSafe
-class GroupMessageItem extends ThreadItem {
+public class GroupMessageItem extends ThreadItem {
 
 	private final GroupId groupId;
 
-	private GroupMessageItem(MessageId messageId, GroupId groupId,
-			@Nullable MessageId parentId, String text, long timestamp,
-			Author author, AuthorInfo authorInfo, boolean isRead) {
-		super(messageId, parentId, text, timestamp, author, authorInfo, isRead);
-		this.groupId = groupId;
-	}
-
-	GroupMessageItem(GroupMessageHeader h, String text) {
-		this(h.getId(), h.getGroupId(), h.getParentId(), text, h.getTimestamp(),
-				h.getAuthor(), h.getAuthorInfo(), h.isRead());
+	GroupMessageItem(GroupMessageHeader h) {
+		super(h.getId(), h.getParentId(), h.getTimestamp(), h.getAuthor(),
+				h.getAuthorInfo(), h.isRead());
+		this.groupId = h.getGroupId();
 	}
 
 	public GroupId getGroupId() {

briar-android/src/main/java/org/briarproject/briar/android/privategroup/conversation/GroupViewModel.java

@@ -99,7 +99,7 @@ class GroupViewModel extends ThreadListViewModel<GroupMessageItem> {
 			// only act on non-local messages in this group
 			if (!g.isLocal() && g.getGroupId().equals(groupId)) {
 				LOG.info("Group message received, adding...");
-				GroupMessageItem item = buildItem(g.getHeader(), g.getText());
+				GroupMessageItem item = buildItem(g.getHeader());
 				addItem(item, false);
 				// In case the join message comes from the creator,
 				// we need to reload the sharing contacts
@@ -167,33 +167,19 @@ class GroupViewModel extends ThreadListViewModel<GroupMessageItem> {
 			List<GroupMessageHeader> headers =
 					privateGroupManager.getHeaders(txn, groupId);
 			logDuration(LOG, "Loading headers", start);
-			start = now();
 			List<GroupMessageItem> items = new ArrayList<>();
 			for (GroupMessageHeader header : headers) {
-				items.add(loadItem(txn, header));
+				items.add(buildItem(header));
 			}
-			logDuration(LOG, "Loading bodies and creating items", start);
 			return items;
 		}, this::setItems);
 	}
 
-	private GroupMessageItem loadItem(Transaction txn,
-			GroupMessageHeader header) throws DbException {
-		String text;
+	private GroupMessageItem buildItem(GroupMessageHeader header) {
 		if (header instanceof JoinMessageHeader) {
-			// will be looked up later
-			text = "";
-		} else {
-			text = privateGroupManager.getMessageText(txn, header.getId());
+			return new JoinMessageItem((JoinMessageHeader) header);
 		}
-		return buildItem(header, text);
-	}
-
-	private GroupMessageItem buildItem(GroupMessageHeader header, String text) {
-		if (header instanceof JoinMessageHeader) {
-			return new JoinMessageItem((JoinMessageHeader) header, text);
-		}
-		return new GroupMessageItem(header, text);
+		return new GroupMessageItem(header);
 	}
 
 	@Override
@@ -221,19 +207,17 @@ class GroupViewModel extends ThreadListViewModel<GroupMessageItem> {
 			LOG.info("Creating group message...");
 			GroupMessage msg = groupMessageFactory.createGroupMessage(groupId,
 					timestamp, parentId, author, text, previousMsgId);
-			storePost(msg, text);
+			storePost(msg);
 		});
 	}
 
-	private void storePost(GroupMessage msg, String text) {
+	private void storePost(GroupMessage msg) {
 		runOnDbThread(false, txn -> {
 			long start = now();
 			GroupMessageHeader header =
 					privateGroupManager.addLocalMessage(txn, msg);
 			logDuration(LOG, "Storing group message", start);
-			txn.attach(() ->
-					addItem(buildItem(header, text), true)
-			);
+			txn.attach(() -> addItem(buildItem(header), true));
 		}, this::handleException);
 	}
 
@@ -284,4 +268,9 @@ class GroupViewModel extends ThreadListViewModel<GroupMessageItem> {
 		return isDissolved;
 	}
 
+	@Override
+	protected String getMessageText(Transaction txn, MessageId m)
+			throws DbException {
+		return privateGroupManager.getMessageText(txn, m);
+	}
 }

briar-android/src/main/java/org/briarproject/briar/android/privategroup/conversation/JoinMessageItem.java

@@ -14,8 +14,8 @@ class JoinMessageItem extends GroupMessageItem {
 
 	private final boolean isInitial;
 
-	JoinMessageItem(JoinMessageHeader h, String text) {
-		super(h, text);
+	JoinMessageItem(JoinMessageHeader h) {
+		super(h);
 		isInitial = h.isInitial();
 	}
 

briar-android/src/main/java/org/briarproject/briar/android/privategroup/conversation/JoinMessageItemViewHolder.java

@@ -9,6 +9,7 @@ import org.briarproject.briar.android.threaded.ThreadItemAdapter.ThreadItemListe
 import org.briarproject.nullsafety.NotNullByDefault;
 
 import androidx.annotation.UiThread;
+import androidx.lifecycle.LifecycleOwner;
 
 import static org.briarproject.briar.api.identity.AuthorInfo.Status.OURSELVES;
 
@@ -25,10 +26,8 @@ class JoinMessageItemViewHolder
 	}
 
 	@Override
-	public void bind(GroupMessageItem item,
+	protected void setText(GroupMessageItem item, LifecycleOwner lifecycleOwner,
 			ThreadItemListener<GroupMessageItem> listener) {
-		super.bind(item, listener);
-
 		if (isCreator) bindForCreator((JoinMessageItem) item);
 		else bind((JoinMessageItem) item);
 	}

briar-android/src/main/java/org/briarproject/briar/android/threaded/BaseThreadItemViewHolder.java

@@ -4,35 +4,46 @@ import android.animation.Animator;
 import android.animation.ArgbEvaluator;
 import android.animation.ValueAnimator;
 import android.content.Context;
-import android.text.util.Linkify;
 import android.view.View;
 import android.view.ViewGroup;
 import android.view.animation.AccelerateInterpolator;
 import android.widget.TextView;
 
-import org.briarproject.bramble.util.StringUtils;
 import org.briarproject.briar.R;
 import org.briarproject.briar.android.threaded.ThreadItemAdapter.ThreadItemListener;
 import org.briarproject.briar.android.view.AuthorView;
 import org.briarproject.nullsafety.NotNullByDefault;
 
+import javax.annotation.Nullable;
+
 import androidx.annotation.CallSuper;
 import androidx.annotation.UiThread;
+import androidx.lifecycle.LifecycleOwner;
+import androidx.lifecycle.LiveData;
+import androidx.lifecycle.Observer;
 import androidx.recyclerview.widget.RecyclerView;
 
+import static android.text.util.Linkify.WEB_URLS;
+import static android.text.util.Linkify.addLinks;
 import static androidx.core.content.ContextCompat.getColor;
+import static org.briarproject.bramble.util.StringUtils.trim;
 import static org.briarproject.briar.android.util.UiUtils.makeLinksClickable;
+import static org.briarproject.nullsafety.NullSafety.requireNonNull;
 
 @UiThread
 @NotNullByDefault
 public abstract class BaseThreadItemViewHolder<I extends ThreadItem>
-		extends RecyclerView.ViewHolder {
+		extends RecyclerView.ViewHolder implements Observer<String> {
 
 	private final static int ANIMATION_DURATION = 5000;
 
 	protected final TextView textView;
 	private final ViewGroup layout;
 	private final AuthorView author;
+	@Nullable
+	private ThreadItemListener<I> listener = null;
+	@Nullable
+	private LiveData<String> textLiveData = null;
 
 	public BaseThreadItemViewHolder(View v) {
 		super(v);
@@ -43,10 +54,9 @@ public abstract class BaseThreadItemViewHolder<I extends ThreadItem>
 	}
 
 	@CallSuper
-	public void bind(I item, ThreadItemListener<I> listener) {
-		textView.setText(StringUtils.trim(item.getText()));
-		Linkify.addLinks(textView, Linkify.WEB_URLS);
-		makeLinksClickable(textView, listener::onLinkClick);
+	public void bind(I item, LifecycleOwner lifecycleOwner,
+			ThreadItemListener<I> listener) {
+		setText(item, lifecycleOwner, listener);
 
 		author.setAuthor(item.getAuthor(), item.getAuthorInfo());
 		author.setDate(item.getTimestamp());
@@ -61,6 +71,20 @@ public abstract class BaseThreadItemViewHolder<I extends ThreadItem>
 		}
 	}
 
+	protected void setText(I item, LifecycleOwner lifecycleOwner,
+			ThreadItemListener<I> listener) {
+		// Clear any existing text while we asynchronously load the new text
+		textView.setText(null);
+		// Remember the listener so we can use it to create links later
+		this.listener = listener;
+		// If the view has been re-bound and we're already asynchronously
+		// loading text for another item, stop observing it
+		if (textLiveData != null) textLiveData.removeObserver(this);
+		// Asynchronously load the text for this item and observe the result
+		textLiveData = listener.loadItemText(item.getId());
+		textLiveData.observe(lifecycleOwner, this);
+	}
+
 	private void animateFadeOut() {
 		setIsRecyclable(false);
 		ValueAnimator anim = new ValueAnimator();
@@ -73,6 +97,7 @@ public abstract class BaseThreadItemViewHolder<I extends ThreadItem>
 			@Override
 			public void onAnimationStart(Animator animation) {
 			}
+
 			@Override
 			public void onAnimationEnd(Animator animation) {
 				layout.setBackgroundResource(
@@ -80,9 +105,11 @@ public abstract class BaseThreadItemViewHolder<I extends ThreadItem>
 				layout.setActivated(false);
 				setIsRecyclable(true);
 			}
+
 			@Override
 			public void onAnimationCancel(Animator animation) {
 			}
+
 			@Override
 			public void onAnimationRepeat(Animator animation) {
 			}
@@ -97,4 +124,24 @@ public abstract class BaseThreadItemViewHolder<I extends ThreadItem>
 		return textView.getContext();
 	}
 
+	void onViewRecycled() {
+		textView.setText(null);
+		if (textLiveData != null) {
+			textLiveData.removeObserver(this);
+			textLiveData = null;
+			listener = null;
+		}
+	}
+
+	@Override
+	public void onChanged(String s) {
+		if (textLiveData != null) {
+			textLiveData.removeObserver(this);
+			textLiveData = null;
+			textView.setText(trim(s));
+			addLinks(textView, WEB_URLS);
+			makeLinksClickable(textView, requireNonNull(listener)::onLinkClick);
+			listener = null;
+		}
+	}
 }

briar-android/src/main/java/org/briarproject/briar/android/threaded/ThreadItem.java

@@ -19,7 +19,6 @@ public abstract class ThreadItem implements MessageNode {
 	private final MessageId messageId;
 	@Nullable
 	private final MessageId parentId;
-	private final String text;
 	private final long timestamp;
 	private final Author author;
 	private final AuthorInfo authorInfo;
@@ -27,11 +26,10 @@ public abstract class ThreadItem implements MessageNode {
 	private boolean isRead, highlighted;
 
 	public ThreadItem(MessageId messageId, @Nullable MessageId parentId,
-			String text, long timestamp, Author author, AuthorInfo authorInfo,
+			long timestamp, Author author, AuthorInfo authorInfo,
 			boolean isRead) {
 		this.messageId = messageId;
 		this.parentId = parentId;
-		this.text = text;
 		this.timestamp = timestamp;
 		this.author = author;
 		this.authorInfo = authorInfo;
@@ -39,10 +37,6 @@ public abstract class ThreadItem implements MessageNode {
 		this.highlighted = false;
 	}
 
-	public String getText() {
-		return text;
-	}
-
 	public int getLevel() {
 		return level;
 	}

briar-android/src/main/java/org/briarproject/briar/android/threaded/ThreadItemAdapter.java

@@ -13,6 +13,8 @@ import javax.annotation.Nullable;
 
 import androidx.annotation.NonNull;
 import androidx.annotation.UiThread;
+import androidx.lifecycle.LifecycleOwner;
+import androidx.lifecycle.LiveData;
 import androidx.recyclerview.widget.DiffUtil;
 import androidx.recyclerview.widget.LinearLayoutManager;
 import androidx.recyclerview.widget.ListAdapter;
@@ -27,9 +29,11 @@ public class ThreadItemAdapter<I extends ThreadItem>
 
 	static final int UNDEFINED = -1;
 
+	private final LifecycleOwner lifecycleOwner;
 	private final ThreadItemListener<I> listener;
 
-	public ThreadItemAdapter(ThreadItemListener<I> listener) {
+	public ThreadItemAdapter(LifecycleOwner lifecycleOwner,
+			ThreadItemListener<I> listener) {
 		super(new DiffUtil.ItemCallback<I>() {
 			@Override
 			public boolean areItemsTheSame(I a, I b) {
@@ -42,6 +46,7 @@ public class ThreadItemAdapter<I extends ThreadItem>
 						a.isRead() == b.isRead();
 			}
 		});
+		this.lifecycleOwner = lifecycleOwner;
 		this.listener = listener;
 	}
 
@@ -58,7 +63,7 @@ public class ThreadItemAdapter<I extends ThreadItem>
 	public void onBindViewHolder(@NonNull BaseThreadItemViewHolder<I> ui,
 			int position) {
 		I item = getItem(position);
-		ui.bind(item, listener);
+		ui.bind(item, lifecycleOwner, listener);
 	}
 
 	int findItemPosition(MessageId id) {
@@ -135,9 +140,19 @@ public class ThreadItemAdapter<I extends ThreadItem>
 		return getItem(position);
 	}
 
+	@Override
+	public void onViewRecycled(BaseThreadItemViewHolder<I> viewHolder) {
+		super.onViewRecycled(viewHolder);
+		viewHolder.onViewRecycled();
+	}
+
 	public interface ThreadItemListener<I> {
+
 		void onReplyClick(I item);
+
 		void onLinkClick(String url);
+
+		LiveData<String> loadItemText(MessageId m);
 	}
 
 }

briar-android/src/main/java/org/briarproject/briar/android/threaded/ThreadListActivity.java

@@ -85,6 +85,9 @@ public abstract class ThreadListActivity<I extends ThreadItem, A extends ThreadI
 		scrollListener = new ThreadScrollListener<>(adapter, viewModel,
 				upButton, downButton);
 		list.getRecyclerView().addOnScrollListener(scrollListener);
+		// This is a tradeoff between memory consumption for cached views
+		// and the cost of loading message text from the database
+		list.getRecyclerView().setItemViewCacheSize(20);
 
 		upButton.setOnClickListener(v -> {
 			int position = adapter.getVisibleUnreadPosTop(layoutManager);
@@ -257,4 +260,8 @@ public abstract class ThreadListActivity<I extends ThreadItem, A extends ThreadI
 
 	protected abstract int getMaxTextLength();
 
+	@Override
+	public LiveData<String> loadItemText(MessageId m) {
+		return getViewModel().loadMessageText(m);
+	}
 }

briar-android/src/main/java/org/briarproject/briar/android/threaded/ThreadListViewModel.java

@@ -6,6 +6,7 @@ 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.NoSuchGroupException;
+import org.briarproject.bramble.api.db.Transaction;
 import org.briarproject.bramble.api.db.TransactionManager;
 import org.briarproject.bramble.api.event.Event;
 import org.briarproject.bramble.api.event.EventBus;
@@ -260,4 +261,14 @@ public abstract class ThreadListViewModel<I extends ThreadItem>
 		return scrollToItem.getAndSet(null);
 	}
 
+	public LiveData<String> loadMessageText(MessageId m) {
+		MutableLiveData<String> textLiveData = new MutableLiveData<>();
+		runOnDbThread(true, txn ->
+						textLiveData.postValue(getMessageText(txn, m)),
+				this::handleException);
+		return textLiveData;
+	}
+
+	protected abstract String getMessageText(Transaction txn, MessageId m)
+			throws DbException;
 }

briar-android/src/main/java/org/briarproject/briar/android/threaded/ThreadPostViewHolder.java

@@ -10,6 +10,7 @@ import org.briarproject.nullsafety.NotNullByDefault;
 import java.util.Locale;
 
 import androidx.annotation.UiThread;
+import androidx.lifecycle.LifecycleOwner;
 
 import static android.view.View.GONE;
 import static android.view.View.VISIBLE;
@@ -40,8 +41,9 @@ public class ThreadPostViewHolder<I extends ThreadItem>
 	}
 
 	@Override
-	public void bind(I item, ThreadItemListener<I> listener) {
-		super.bind(item, listener);
+	public void bind(I item, LifecycleOwner lifecycleOwner,
+			ThreadItemListener<I> listener) {
+		super.bind(item, lifecycleOwner, listener);
 
 		for (int i = 0; i < lvls.length; i++) {
 			lvls[i].setVisibility(i < item.getLevel() ? VISIBLE : GONE);

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

@@ -11,7 +11,6 @@
 		android:layout_width="@dimen/listitem_picture_frame_size"
 		android:layout_height="@dimen/listitem_picture_frame_size"
 		android:layout_marginStart="@dimen/listitem_horizontal_margin"
-		android:layout_marginLeft="@dimen/listitem_horizontal_margin"
 		app:layout_constraintBottom_toTopOf="@+id/divider"
 		app:layout_constraintStart_toStartOf="parent"
 		app:layout_constraintTop_toTopOf="parent" />
@@ -38,7 +37,6 @@
 		android:layout_height="wrap_content"
 		android:layout_marginTop="@dimen/margin_medium"
 		android:layout_marginEnd="8dp"
-		android:layout_marginRight="8dp"
 		android:textColor="?android:attr/textColorSecondary"
 		android:textSize="@dimen/text_size_small"
 		app:layout_constraintEnd_toStartOf="@+id/dateView"
@@ -51,7 +49,6 @@
 		android:layout_width="wrap_content"
 		android:layout_height="wrap_content"
 		android:layout_marginEnd="@dimen/listitem_horizontal_margin"
-		android:layout_marginRight="@dimen/listitem_horizontal_margin"
 		android:textColor="?android:attr/textColorSecondary"
 		android:textSize="@dimen/text_size_small"
 		app:layout_constraintBaseline_toBaselineOf="@+id/postCountView"
@@ -63,7 +60,6 @@
 		style="@style/Divider.ThreadItem"
 		android:layout_width="0dp"
 		android:layout_marginStart="@dimen/margin_medium"
-		android:layout_marginLeft="@dimen/margin_medium"
 		android:layout_marginTop="@dimen/listitem_horizontal_margin"
 		app:layout_constraintBottom_toBottomOf="parent"
 		app:layout_constraintEnd_toEndOf="parent"

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

@@ -0,0 +1,8 @@
+<?xml version="1.0" encoding="utf-8"?>
+<menu xmlns:android="http://schemas.android.com/apk/res/android">
+
+	<item
+		android:id="@+id/action_forum_delete"
+		android:title="@string/forum_leave" />
+
+</menu>

briar-api/src/main/java/org/briarproject/briar/api/forum/event/ForumPostReceivedEvent.java

@@ -16,13 +16,10 @@ public class ForumPostReceivedEvent extends Event {
 
 	private final GroupId groupId;
 	private final ForumPostHeader header;
-	private final String text;
 
-	public ForumPostReceivedEvent(GroupId groupId, ForumPostHeader header,
-			String text) {
+	public ForumPostReceivedEvent(GroupId groupId, ForumPostHeader header) {
 		this.groupId = groupId;
 		this.header = header;
-		this.text = text;
 	}
 
 	public GroupId getGroupId() {
@@ -32,8 +29,4 @@ public class ForumPostReceivedEvent extends Event {
 	public ForumPostHeader getHeader() {
 		return header;
 	}
-
-	public String getText() {
-		return text;
-	}
 }

briar-api/src/main/java/org/briarproject/briar/api/privategroup/event/GroupMessageAddedEvent.java

@@ -17,14 +17,12 @@ public class GroupMessageAddedEvent extends Event {
 
 	private final GroupId groupId;
 	private final GroupMessageHeader header;
-	private final String text;
 	private final boolean local;
 
 	public GroupMessageAddedEvent(GroupId groupId, GroupMessageHeader header,
-			String text, boolean local) {
+			boolean local) {
 		this.groupId = groupId;
 		this.header = header;
-		this.text = text;
 		this.local = local;
 	}
 
@@ -36,10 +34,6 @@ public class GroupMessageAddedEvent extends Event {
 		return header;
 	}
 
-	public String getText() {
-		return text;
-	}
-
 	public boolean isLocal() {
 		return local;
 	}

briar-core/src/main/java/org/briarproject/briar/forum/ForumManagerImpl.java

@@ -83,10 +83,7 @@ class ForumManagerImpl extends BdfIncomingMessageHook implements ForumManager {
 		messageTracker.trackIncomingMessage(txn, m);
 
 		ForumPostHeader header = getForumPostHeader(txn, m.getId(), meta);
-		String text = getPostText(body);
-		ForumPostReceivedEvent event =
-				new ForumPostReceivedEvent(m.getGroupId(), header, text);
-		txn.attach(event);
+		txn.attach(new ForumPostReceivedEvent(m.getGroupId(), header));
 
 		return ACCEPT_SHARE;
 	}

briar-core/src/main/java/org/briarproject/briar/privategroup/PrivateGroupManagerImpl.java

@@ -170,6 +170,7 @@ class PrivateGroupManagerImpl extends BdfIncomingMessageHook
 				txn -> getPreviousMsgId(txn, g));
 	}
 
+	@Override
 	public MessageId getPreviousMsgId(Transaction txn, GroupId g)
 			throws DbException {
 		try {
@@ -605,9 +606,7 @@ class PrivateGroupManagerImpl extends BdfIncomingMessageHook
 			throws DbException, FormatException {
 		GroupMessageHeader header = getGroupMessageHeader(txn, m.getGroupId(),
 				m.getId(), meta, Collections.emptyMap());
-		String text = getMessageText(clientHelper.toList(m));
-		txn.attach(new GroupMessageAddedEvent(m.getGroupId(), header, text,
-				local));
+		txn.attach(new GroupMessageAddedEvent(m.getGroupId(), header, local));
 	}
 
 	private void attachJoinMessageAddedEvent(Transaction txn, Message m,
@@ -615,8 +614,7 @@ class PrivateGroupManagerImpl extends BdfIncomingMessageHook
 			throws DbException, FormatException {
 		JoinMessageHeader header = getJoinMessageHeader(txn, m.getGroupId(),
 				m.getId(), meta, Collections.emptyMap());
-		txn.attach(new GroupMessageAddedEvent(m.getGroupId(), header, "",
-				local));
+		txn.attach(new GroupMessageAddedEvent(m.getGroupId(), header, local));
 	}
 
 	private void addMember(Transaction txn, GroupId g, Author a, Visibility v)

dagger.gradle

@@ -6,9 +6,9 @@ sourceSets.configureEach { sourceSet ->
 
 idea {
 	module {
-		sourceDirs += compileJava.options.generatedSourceOutputDirectory
-		generatedSourceDirs += compileJava.options.generatedSourceOutputDirectory
-		testSourceDirs += compileTestJava.options.generatedSourceOutputDirectory
-		generatedSourceDirs += compileTestJava.options.generatedSourceOutputDirectory
+		sourceDirs += compileJava.options.generatedSourceOutputDirectory.get().getAsFile()
+		generatedSourceDirs += compileJava.options.generatedSourceOutputDirectory.get().getAsFile()
+		testSourceDirs += compileTestJava.options.generatedSourceOutputDirectory.get().getAsFile()
+		generatedSourceDirs += compileTestJava.options.generatedSourceOutputDirectory.get().getAsFile()
 	}
 }