Move thread list events, fields and notification handling into ViewModels

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

@@ -26,7 +26,6 @@ import javax.inject.Inject;
 import androidx.appcompat.app.AlertDialog;
 import androidx.appcompat.widget.Toolbar;
 import androidx.lifecycle.ViewModelProvider;
-import androidx.recyclerview.widget.LinearLayoutManager;
 
 import static android.content.Intent.FLAG_ACTIVITY_CLEAR_TOP;
 import static org.briarproject.briar.android.activity.RequestCodes.REQUEST_SHARE_FORUM;
@@ -63,6 +62,11 @@ public class ForumActivity extends
 		return viewModel;
 	}
 
+	@Override
+	protected ThreadItemAdapter<ForumPostItem> createAdapter() {
+		return new ThreadItemAdapter<>(this);
+	}
+
 	@Override
 	public void onCreate(@Nullable Bundle state) {
 		super.onCreate(state);
@@ -91,9 +95,9 @@ public class ForumActivity extends
 	}
 
 	@Override
-	protected ThreadItemAdapter<ForumPostItem> createAdapter(
-			LinearLayoutManager layoutManager) {
-		return new ThreadItemAdapter<>(this, layoutManager);
+	public void onStart() {
+		super.onStart();
+		viewModel.clearForumPostNotification();
 	}
 
 	@Override

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

@@ -17,10 +17,8 @@ import org.briarproject.briar.android.threaded.ThreadListControllerImpl;
 import org.briarproject.briar.api.android.AndroidNotificationManager;
 import org.briarproject.briar.api.forum.ForumInvitationResponse;
 import org.briarproject.briar.api.forum.ForumManager;
-import org.briarproject.briar.api.forum.ForumPostHeader;
 import org.briarproject.briar.api.forum.ForumSharingManager;
 import org.briarproject.briar.api.forum.event.ForumInvitationResponseReceivedEvent;
-import org.briarproject.briar.api.forum.event.ForumPostReceivedEvent;
 import org.briarproject.briar.api.sharing.event.ContactLeftShareableEvent;
 
 import java.util.ArrayList;
@@ -59,7 +57,6 @@ class ForumControllerImpl extends ThreadListControllerImpl<ForumPostItem>
 	@Override
 	public void onActivityStart() {
 		super.onActivityStart();
-		notificationManager.clearForumPostNotification(getGroupId());
 	}
 
 	@Override
@@ -68,13 +65,7 @@ class ForumControllerImpl extends ThreadListControllerImpl<ForumPostItem>
 
 		ForumListener listener = (ForumListener) this.listener;
 
-		if (e instanceof ForumPostReceivedEvent) {
-			ForumPostReceivedEvent f = (ForumPostReceivedEvent) e;
-			if (f.getGroupId().equals(getGroupId())) {
-				LOG.info("Forum post received, adding...");
-				listener.onItemReceived(buildItem(f.getHeader(), f.getText()));
-			}
-		} else if (e instanceof ForumInvitationResponseReceivedEvent) {
+		if (e instanceof ForumInvitationResponseReceivedEvent) {
 			ForumInvitationResponseReceivedEvent f =
 					(ForumInvitationResponseReceivedEvent) e;
 			ForumInvitationResponse r = f.getMessageHeader();
@@ -114,8 +105,4 @@ class ForumControllerImpl extends ThreadListControllerImpl<ForumPostItem>
 		});
 	}
 
-	private ForumPostItem buildItem(ForumPostHeader header, String text) {
-		return new ForumPostItem(header, text);
-	}
-
 }

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

@@ -29,6 +29,7 @@ import org.briarproject.briar.api.forum.ForumManager;
 import org.briarproject.briar.api.forum.ForumPost;
 import org.briarproject.briar.api.forum.ForumPostHeader;
 import org.briarproject.briar.api.forum.ForumSharingManager;
+import org.briarproject.briar.api.forum.event.ForumPostReceivedEvent;
 
 import java.util.List;
 import java.util.concurrent.Executor;
@@ -80,7 +81,20 @@ class ForumViewModel extends ThreadListViewModel<ForumPostItem> {
 
 	@Override
 	public void eventOccurred(Event e) {
+		if (e instanceof ForumPostReceivedEvent) {
+			ForumPostReceivedEvent f = (ForumPostReceivedEvent) e;
+			if (f.getGroupId().equals(groupId)) {
+				LOG.info("Forum post received, adding...");
+				ForumPostItem item = buildItem(f.getHeader(), f.getText());
+				addItem(item);
+			}
+		} else {
+			super.eventOccurred(e);
+		}
+	}
 
+	void clearForumPostNotification() {
+		notificationManager.clearForumPostNotification(groupId);
 	}
 
 	LiveData<Forum> loadForum() {
@@ -141,7 +155,7 @@ class ForumViewModel extends ThreadListViewModel<ForumPostItem> {
 				long start = now();
 				ForumPostHeader header = forumManager.addLocalPost(msg);
 				textCache.put(msg.getMessage().getId(), text);
-				addItem(buildItem(header, text), true);
+				addItemAsync(buildItem(header, text));
 				logDuration(LOG, "Storing forum post", start);
 			} catch (DbException e) {
 				logException(LOG, WARNING, e);

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

@@ -7,13 +7,11 @@ import android.view.MenuInflater;
 import android.view.MenuItem;
 
 import org.briarproject.bramble.api.contact.ContactId;
-import org.briarproject.bramble.api.db.DbException;
 import org.briarproject.bramble.api.identity.AuthorId;
 import org.briarproject.bramble.api.nullsafety.MethodsNotNullByDefault;
 import org.briarproject.bramble.api.nullsafety.ParametersNotNullByDefault;
 import org.briarproject.briar.R;
 import org.briarproject.briar.android.activity.ActivityComponent;
-import org.briarproject.briar.android.controller.handler.UiResultExceptionHandler;
 import org.briarproject.briar.android.privategroup.conversation.GroupController.GroupListener;
 import org.briarproject.briar.android.privategroup.creation.GroupInviteActivity;
 import org.briarproject.briar.android.privategroup.memberlist.GroupMemberListActivity;
@@ -29,7 +27,6 @@ import javax.inject.Inject;
 import androidx.appcompat.app.AlertDialog;
 import androidx.appcompat.widget.Toolbar;
 import androidx.lifecycle.ViewModelProvider;
-import androidx.recyclerview.widget.LinearLayoutManager;
 
 import static android.view.View.GONE;
 import static android.view.View.VISIBLE;
@@ -50,9 +47,6 @@ public class GroupActivity extends
 
 	private GroupViewModel viewModel;
 
-	@Nullable
-	private Boolean isCreator = null;
-	private boolean isDissolved = false;
 	private MenuItem revealMenuItem, inviteMenuItem, leaveMenuItem,
 			dissolveMenuItem;
 
@@ -73,6 +67,11 @@ public class GroupActivity extends
 		return viewModel;
 	}
 
+	@Override
+	protected GroupMessageAdapter createAdapter() {
+		return new GroupMessageAdapter(this);
+	}
+
 	@Override
 	public void onCreate(@Nullable Bundle state) {
 		super.onCreate(state);
@@ -85,11 +84,7 @@ public class GroupActivity extends
 		observeOnce(viewModel.getPrivateGroup(), this, privateGroup ->
 				setTitle(privateGroup.getName())
 		);
-		observeOnce(viewModel.isCreator(), this, isCreator -> {
-			this.isCreator = isCreator; // TODO remove field
-			adapter.setPerspective(isCreator);
-			showMenuItems();
-		});
+		observeOnce(viewModel.isCreator(), this, adapter::setIsCreator);
 
 		// Open member list on Toolbar click
 		if (toolbar != null) {
@@ -101,25 +96,18 @@ public class GroupActivity extends
 			});
 		}
 
+		// start with group disabled and enable when not dissolved
 		setGroupEnabled(false);
-		controller.isDissolved(
-				new UiResultExceptionHandler<Boolean, DbException>(this) {
-					@Override
-					public void onResultUi(Boolean isDissolved) {
-						setGroupEnabled(!isDissolved);
-					}
-
-					@Override
-					public void onExceptionUi(DbException exception) {
-						handleException(exception);
-					}
-				});
+		viewModel.isDissolved().observe(this, dissolved -> {
+			setGroupEnabled(!dissolved);
+			if (dissolved) onGroupDissolved();
+		});
 	}
 
 	@Override
-	protected GroupMessageAdapter createAdapter(
-			LinearLayoutManager layoutManager) {
-		return new GroupMessageAdapter(this, layoutManager);
+	public void onStart() {
+		super.onStart();
+		viewModel.clearGroupMessageNotifications();
 	}
 
 	@Override
@@ -139,8 +127,13 @@ public class GroupActivity extends
 		leaveMenuItem.setVisible(false);
 		dissolveMenuItem.setVisible(false);
 
-		// show items based on role
-		showMenuItems();
+		// show items based on role (which will not change, so observe once)
+		observeOnce(viewModel.isCreator(), this, isCreator -> {
+			revealMenuItem.setVisible(!isCreator);
+			inviteMenuItem.setVisible(isCreator);
+			leaveMenuItem.setVisible(!isCreator);
+			dissolveMenuItem.setVisible(isCreator);
+		});
 
 		return super.onCreateOptionsMenu(menu);
 	}
@@ -154,26 +147,26 @@ public class GroupActivity extends
 			startActivity(i1);
 			return true;
 		} else if (itemId == R.id.action_group_reveal) {
-			if (isCreator == null || isCreator)
+			if (viewModel.isCreator().getValue())
 				throw new IllegalStateException();
 			Intent i2 = new Intent(this, RevealContactsActivity.class);
 			i2.putExtra(GROUP_ID, groupId.getBytes());
 			startActivity(i2);
 			return true;
 		} else if (itemId == R.id.action_group_invite) {
-			if (isCreator == null || !isCreator)
+			if (!viewModel.isCreator().getValue())
 				throw new IllegalStateException();
 			Intent i3 = new Intent(this, GroupInviteActivity.class);
 			i3.putExtra(GROUP_ID, groupId.getBytes());
 			startActivityForResult(i3, REQUEST_GROUP_INVITE);
 			return true;
 		} else if (itemId == R.id.action_group_leave) {
-			if (isCreator == null || isCreator)
+			if (viewModel.isCreator().getValue())
 				throw new IllegalStateException();
 			showLeaveGroupDialog();
 			return true;
 		} else if (itemId == R.id.action_group_dissolve) {
-			if (isCreator == null || !isCreator)
+			if (!viewModel.isCreator().getValue())
 				throw new IllegalStateException();
 			showDissolveGroupDialog();
 
@@ -190,14 +183,6 @@ public class GroupActivity extends
 		} else super.onActivityResult(request, result, data);
 	}
 
-	@Override
-	public void onItemReceived(GroupMessageItem item) {
-		super.onItemReceived(item);
-		if (item instanceof JoinMessageItem) {
-			if (((JoinMessageItem) item).isInitial()) loadSharingContacts();
-		}
-	}
-
 	@Override
 	protected int getMaxTextLength() {
 		return MAX_GROUP_POST_TEXT_LENGTH;
@@ -205,11 +190,10 @@ public class GroupActivity extends
 
 	@Override
 	public void onReplyClick(GroupMessageItem item) {
-		if (!isDissolved) super.onReplyClick(item);
+		if (!viewModel.isDissolved().getValue()) super.onReplyClick(item);
 	}
 
 	private void setGroupEnabled(boolean enabled) {
-		isDissolved = !enabled;
 		sendController.setReady(enabled);
 		list.getRecyclerView().setAlpha(enabled ? 1f : 0.5f);
 
@@ -221,15 +205,6 @@ public class GroupActivity extends
 		}
 	}
 
-	private void showMenuItems() {
-		// we need to have the menu items and know if we are the creator
-		if (leaveMenuItem == null || isCreator == null) return;
-		revealMenuItem.setVisible(!isCreator);
-		inviteMenuItem.setVisible(isCreator);
-		leaveMenuItem.setVisible(!isCreator);
-		dissolveMenuItem.setVisible(isCreator);
-	}
-
 	private void showLeaveGroupDialog() {
 		AlertDialog.Builder builder =
 				new AlertDialog.Builder(this, R.style.BriarDialogTheme);
@@ -268,7 +243,6 @@ public class GroupActivity extends
 				sharingController.getOnlineCount());
 	}
 
-	@Override
 	public void onGroupDissolved() {
 		setGroupEnabled(false);
 		AlertDialog.Builder builder =

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

@@ -1,9 +1,7 @@
 package org.briarproject.briar.android.privategroup.conversation;
 
 import org.briarproject.bramble.api.contact.ContactId;
-import org.briarproject.bramble.api.db.DbException;
 import org.briarproject.bramble.api.identity.AuthorId;
-import org.briarproject.briar.android.controller.handler.ResultExceptionHandler;
 import org.briarproject.briar.android.threaded.ThreadListController;
 import org.briarproject.briar.api.privategroup.Visibility;
 
@@ -12,17 +10,10 @@ import androidx.annotation.UiThread;
 public interface GroupController
 		extends ThreadListController<GroupMessageItem> {
 
-	void isDissolved(
-			ResultExceptionHandler<Boolean, DbException> handler);
-
 	interface GroupListener extends ThreadListListener<GroupMessageItem> {
-
 		@UiThread
 		void onContactRelationshipRevealed(AuthorId memberId,
 				ContactId contactId, Visibility v);
-
-		@UiThread
-		void onGroupDissolved();
 	}
 
 }

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

@@ -16,13 +16,9 @@ import org.briarproject.briar.android.controller.handler.ResultExceptionHandler;
 import org.briarproject.briar.android.threaded.ThreadListControllerImpl;
 import org.briarproject.briar.api.android.AndroidNotificationManager;
 import org.briarproject.briar.api.privategroup.GroupMember;
-import org.briarproject.briar.api.privategroup.GroupMessageHeader;
-import org.briarproject.briar.api.privategroup.JoinMessageHeader;
 import org.briarproject.briar.api.privategroup.PrivateGroupManager;
 import org.briarproject.briar.api.privategroup.event.ContactRelationshipRevealedEvent;
-import org.briarproject.briar.api.privategroup.event.GroupDissolvedEvent;
 import org.briarproject.briar.api.privategroup.event.GroupInvitationResponseReceivedEvent;
-import org.briarproject.briar.api.privategroup.event.GroupMessageAddedEvent;
 import org.briarproject.briar.api.privategroup.invitation.GroupInvitationResponse;
 
 import java.util.ArrayList;
@@ -61,7 +57,6 @@ class GroupControllerImpl extends ThreadListControllerImpl<GroupMessageItem>
 	@Override
 	public void onActivityStart() {
 		super.onActivityStart();
-		notificationManager.clearGroupMessageNotification(getGroupId());
 	}
 
 	@Override
@@ -70,13 +65,7 @@ class GroupControllerImpl extends ThreadListControllerImpl<GroupMessageItem>
 
 		GroupListener listener = (GroupListener) this.listener;
 
-		if (e instanceof GroupMessageAddedEvent) {
-			GroupMessageAddedEvent g = (GroupMessageAddedEvent) e;
-			if (!g.isLocal() && g.getGroupId().equals(getGroupId())) {
-				LOG.info("Group message received, adding...");
-				listener.onItemReceived(buildItem(g.getHeader(), g.getText()));
-			}
-		} else if (e instanceof ContactRelationshipRevealedEvent) {
+		if (e instanceof ContactRelationshipRevealedEvent) {
 			ContactRelationshipRevealedEvent c =
 					(ContactRelationshipRevealedEvent) e;
 			if (getGroupId().equals(c.getGroupId())) {
@@ -90,11 +79,6 @@ class GroupControllerImpl extends ThreadListControllerImpl<GroupMessageItem>
 			if (getGroupId().equals(r.getShareableId()) && r.wasAccepted()) {
 				listener.onInvitationAccepted(g.getContactId());
 			}
-		} else if (e instanceof GroupDissolvedEvent) {
-			GroupDissolvedEvent g = (GroupDissolvedEvent) e;
-			if (getGroupId().equals(g.getGroupId())) {
-				listener.onGroupDissolved();
-			}
 		}
 	}
 
@@ -123,26 +107,4 @@ class GroupControllerImpl extends ThreadListControllerImpl<GroupMessageItem>
 		});
 	}
 
-	private GroupMessageItem buildItem(GroupMessageHeader header, String text) {
-		if (header instanceof JoinMessageHeader) {
-			return new JoinMessageItem((JoinMessageHeader) header, text);
-		}
-		return new GroupMessageItem(header, text);
-	}
-
-	@Override
-	public void isDissolved(
-			ResultExceptionHandler<Boolean, DbException> handler) {
-		runOnDbThread(() -> {
-			try {
-				boolean isDissolved =
-						privateGroupManager.isDissolved(getGroupId());
-				handler.onResult(isDissolved);
-			} catch (DbException e) {
-				logException(LOG, WARNING, e);
-				handler.onException(e);
-			}
-		});
-	}
-
 }

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

@@ -14,7 +14,6 @@ import org.briarproject.briar.api.privategroup.Visibility;
 
 import androidx.annotation.LayoutRes;
 import androidx.annotation.UiThread;
-import androidx.recyclerview.widget.LinearLayoutManager;
 
 import static androidx.recyclerview.widget.RecyclerView.NO_POSITION;
 
@@ -24,9 +23,8 @@ class GroupMessageAdapter extends ThreadItemAdapter<GroupMessageItem> {
 
 	private boolean isCreator = false;
 
-	GroupMessageAdapter(ThreadItemListener<GroupMessageItem> listener,
-			LinearLayoutManager layoutManager) {
-		super(listener, layoutManager);
+	GroupMessageAdapter(ThreadItemListener<GroupMessageItem> listener) {
+		super(listener);
 	}
 
 	@LayoutRes
@@ -47,7 +45,7 @@ class GroupMessageAdapter extends ThreadItemAdapter<GroupMessageItem> {
 		return new ThreadPostViewHolder<>(v);
 	}
 
-	void setPerspective(boolean isCreator) {
+	void setIsCreator(boolean isCreator) {
 		this.isCreator = isCreator;
 		notifyDataSetChanged();
 	}

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

@@ -30,6 +30,8 @@ import org.briarproject.briar.api.privategroup.GroupMessageHeader;
 import org.briarproject.briar.api.privategroup.JoinMessageHeader;
 import org.briarproject.briar.api.privategroup.PrivateGroup;
 import org.briarproject.briar.api.privategroup.PrivateGroupManager;
+import org.briarproject.briar.api.privategroup.event.GroupDissolvedEvent;
+import org.briarproject.briar.api.privategroup.event.GroupMessageAddedEvent;
 
 import java.util.List;
 import java.util.concurrent.Executor;
@@ -60,6 +62,8 @@ class GroupViewModel extends ThreadListViewModel<GroupMessageItem> {
 	private final MutableLiveData<PrivateGroup> privateGroup =
 			new MutableLiveData<>();
 	private final MutableLiveData<Boolean> isCreator = new MutableLiveData<>();
+	private final MutableLiveData<Boolean> isDissolved =
+			new MutableLiveData<>();
 
 	@Inject
 	GroupViewModel(Application application,
@@ -84,7 +88,26 @@ class GroupViewModel extends ThreadListViewModel<GroupMessageItem> {
 
 	@Override
 	public void eventOccurred(Event e) {
-
+		if (e instanceof GroupMessageAddedEvent) {
+			GroupMessageAddedEvent g = (GroupMessageAddedEvent) e;
+			// 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());
+				addItem(item);
+				if (item instanceof JoinMessageItem) {
+					// TODO
+//					if (((JoinMessageItem) item).isInitial()) loadSharingContacts();
+				}
+			}
+		} else if (e instanceof GroupDissolvedEvent) {
+			GroupDissolvedEvent g = (GroupDissolvedEvent) e;
+			if (g.getGroupId().equals(groupId)) {
+				isDissolved.setValue(true);
+			}
+		} else {
+			super.eventOccurred(e);
+		}
 	}
 
 	@Override
@@ -93,6 +116,10 @@ class GroupViewModel extends ThreadListViewModel<GroupMessageItem> {
 		loadPrivateGroup(groupId);
 	}
 
+	public void clearGroupMessageNotifications() {
+		notificationManager.clearGroupMessageNotification(groupId);
+	}
+
 	private void loadPrivateGroup(GroupId groupId) {
 		runOnDbThread(() -> {
 			try {
@@ -109,7 +136,10 @@ class GroupViewModel extends ThreadListViewModel<GroupMessageItem> {
 	@Override
 	public void loadItems() {
 		loadList(txn -> {
-			// TODO first check if group is dissolved
+			// check first if group is dissolved
+			isDissolved
+					.postValue(privateGroupManager.isDissolved(txn, groupId));
+			// no continue to load the items
 			long start = now();
 			List<GroupMessageHeader> headers =
 					privateGroupManager.getHeaders(txn, groupId);
@@ -173,7 +203,7 @@ class GroupViewModel extends ThreadListViewModel<GroupMessageItem> {
 				GroupMessageHeader header =
 						privateGroupManager.addLocalMessage(msg);
 				textCache.put(msg.getMessage().getId(), text);
-				addItem(buildItem(header, text), true);
+				addItemAsync(buildItem(header, text));
 				logDuration(LOG, "Storing group message", start);
 			} catch (DbException e) {
 				logException(LOG, WARNING, e);
@@ -199,4 +229,8 @@ class GroupViewModel extends ThreadListViewModel<GroupMessageItem> {
 		return isCreator;
 	}
 
+	LiveData<Boolean> isDissolved() {
+		return isDissolved;
+	}
+
 }

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

@@ -30,10 +30,8 @@ public class ThreadItemAdapter<I extends ThreadItem>
 	static final int UNDEFINED = -1;
 
 	private final ThreadItemListener<I> listener;
-	private final LinearLayoutManager layoutManager;
 
-	public ThreadItemAdapter(ThreadItemListener<I> listener,
-			LinearLayoutManager layoutManager) {
+	public ThreadItemAdapter(ThreadItemListener<I> listener) {
 		super(new DiffUtil.ItemCallback<I>() {
 			@Override
 			public boolean areItemsTheSame(I a, I b) {
@@ -47,7 +45,6 @@ public class ThreadItemAdapter<I extends ThreadItem>
 			}
 		});
 		this.listener = listener;
-		this.layoutManager = layoutManager;
 	}
 
 	@NonNull
@@ -101,10 +98,17 @@ public class ThreadItemAdapter<I extends ThreadItem>
 		return null;
 	}
 
+	@Nullable
+	MessageId getFirstVisibleMessageId(LinearLayoutManager layoutManager) {
+		int position = layoutManager.findFirstVisibleItemPosition();
+		if (position == NO_POSITION) return null;
+		return getItemAt(position).getId();
+	}
+
 	/**
 	 * Returns the position of the first unread item below the current viewport
 	 */
-	int getVisibleUnreadPosBottom() {
+	int getVisibleUnreadPosBottom(LinearLayoutManager layoutManager) {
 		int positionBottom = layoutManager.findLastVisibleItemPosition();
 		if (positionBottom == NO_POSITION) return NO_POSITION;
 		for (int i = positionBottom + 1; i < getItemCount(); i++) {
@@ -116,7 +120,7 @@ public class ThreadItemAdapter<I extends ThreadItem>
 	/**
 	 * Returns the position of the first unread item above the current viewport
 	 */
-	int getVisibleUnreadPosTop() {
+	int getVisibleUnreadPosTop(LinearLayoutManager layoutManager) {
 		int positionTop = layoutManager.findFirstVisibleItemPosition();
 		int position = NO_POSITION;
 		for (int i = 0; i < getItemCount(); i++) {

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

@@ -2,7 +2,6 @@ package org.briarproject.briar.android.threaded;
 
 import android.content.Intent;
 import android.os.Bundle;
-import android.os.Parcelable;
 import android.view.MenuItem;
 
 import com.google.android.material.snackbar.Snackbar;
@@ -19,7 +18,6 @@ import org.briarproject.briar.android.controller.SharingController;
 import org.briarproject.briar.android.controller.SharingController.SharingListener;
 import org.briarproject.briar.android.controller.handler.UiResultExceptionHandler;
 import org.briarproject.briar.android.threaded.ThreadItemAdapter.ThreadItemListener;
-import org.briarproject.briar.android.threaded.ThreadListController.ThreadListDataSource;
 import org.briarproject.briar.android.threaded.ThreadListController.ThreadListListener;
 import org.briarproject.briar.android.util.BriarSnackbarBuilder;
 import org.briarproject.briar.android.view.BriarRecyclerView;
@@ -31,7 +29,6 @@ import org.briarproject.briar.api.attachment.AttachmentHeader;
 
 import java.util.Collection;
 import java.util.List;
-import java.util.logging.Logger;
 
 import javax.annotation.Nullable;
 import javax.inject.Inject;
@@ -42,7 +39,6 @@ import androidx.appcompat.app.ActionBar;
 import androidx.recyclerview.widget.LinearLayoutManager;
 
 import static androidx.recyclerview.widget.RecyclerView.NO_POSITION;
-import static java.util.logging.Logger.getLogger;
 import static org.briarproject.bramble.util.StringUtils.isNullOrEmpty;
 
 @MethodsNotNullByDefault
@@ -50,30 +46,22 @@ import static org.briarproject.bramble.util.StringUtils.isNullOrEmpty;
 public abstract class ThreadListActivity<I extends ThreadItem, A extends ThreadItemAdapter<I>>
 		extends BriarActivity
 		implements ThreadListListener<I>, SendListener, SharingListener,
-		ThreadItemListener<I>, ThreadListDataSource {
-
-	protected static final String KEY_REPLY_ID = "replyId";
-
-	private static final Logger LOG =
-			getLogger(ThreadListActivity.class.getName());
-
-	protected A adapter;
+		ThreadItemListener<I> {
 
+	protected final A adapter = createAdapter();
 	private ThreadScrollListener<I> scrollListener;
 	protected BriarRecyclerView list;
 	private LinearLayoutManager layoutManager;
 	protected TextInputView textInput;
 	protected TextSendController sendController;
 	protected GroupId groupId;
-	@Nullable
-	private Parcelable layoutManagerState;
-	@Nullable
-	private MessageId replyId;
 
 	protected abstract ThreadListController<I> getController();
 
 	protected abstract ThreadListViewModel<I> getViewModel();
 
+	protected abstract A createAdapter();
+
 	@Inject
 	protected SharingController sharingController;
 
@@ -103,59 +91,85 @@ public abstract class ThreadListActivity<I extends ThreadItem, A extends ThreadI
 		list = findViewById(R.id.list);
 		layoutManager = new LinearLayoutManager(this);
 		list.setLayoutManager(layoutManager);
-		adapter = createAdapter(layoutManager);
 		list.setAdapter(adapter);
 		scrollListener = new ThreadScrollListener<>(adapter, getController(),
 				upButton, downButton);
 		list.getRecyclerView().addOnScrollListener(scrollListener);
 
 		upButton.setOnClickListener(v -> {
-			int position = adapter.getVisibleUnreadPosTop();
+			int position = adapter.getVisibleUnreadPosTop(layoutManager);
 			if (position != NO_POSITION) {
 				list.getRecyclerView().scrollToPosition(position);
 			}
 		});
 		downButton.setOnClickListener(v -> {
-			int position = adapter.getVisibleUnreadPosBottom();
+			int position = adapter.getVisibleUnreadPosBottom(layoutManager);
 			if (position != NO_POSITION) {
 				list.getRecyclerView().scrollToPosition(position);
 			}
 		});
 
-		if (state != null) {
-			byte[] replyIdBytes = state.getByteArray(KEY_REPLY_ID);
-			if (replyIdBytes != null) replyId = new MessageId(replyIdBytes);
-		}
-
 		getViewModel().getItems().observe(this, result -> result
 				.onError(this::handleException)
 				.onSuccess(this::displayItems)
 		);
 
+		getViewModel().getGroupRemoved().observe(this, removed -> {
+			if (removed) supportFinishAfterTransition();
+		});
+
 		sharingController.setSharingListener(this);
 		loadSharingContacts();
 	}
 
+	@CallSuper
+	@Override
+	public void onStart() {
+		super.onStart();
+		getViewModel().blockNotifications();
+		sharingController.onStart();
+		list.startPeriodicUpdate();
+	}
+
+	@CallSuper
+	@Override
+	public void onStop() {
+		super.onStop();
+		getViewModel().unblockNotifications();
+		sharingController.onStop();
+		list.stopPeriodicUpdate();
+	}
+
+	@Override
+	public boolean onOptionsItemSelected(MenuItem item) {
+		if (item.getItemId() == android.R.id.home) {
+			supportFinishAfterTransition();
+			return true;
+		}
+		return super.onOptionsItemSelected(item);
+	}
+
+	@Override
+	public void onBackPressed() {
+		if (adapter.getHighlightedItem() != null) {
+			textInput.clearText();
+			getViewModel().setReplyId(null);
+			updateTextInput();
+		} else {
+			super.onBackPressed();
+		}
+	}
+
 	@Override
 	protected void onDestroy() {
 		super.onDestroy();
-		getViewModel().storeMessageId(getFirstVisibleMessageId());
-	}
-
-	@Override
-	@Nullable
-	public MessageId getFirstVisibleMessageId() {
+		// store list position, so we can restore it when coming back here
 		if (layoutManager != null && adapter != null) {
-			int position =
-					layoutManager.findFirstVisibleItemPosition();
-			I i = adapter.getItemAt(position);
-			return i == null ? null : i.getId();
+			MessageId id = adapter.getFirstVisibleMessageId(layoutManager);
+			getViewModel().storeMessageId(id);
 		}
-		return null;
 	}
 
-	protected abstract A createAdapter(LinearLayoutManager layoutManager);
-
 	protected void displayItems(List<I> items) {
 		if (items.isEmpty()) {
 			list.showData();
@@ -201,58 +215,9 @@ public abstract class ThreadListActivity<I extends ThreadItem, A extends ThreadI
 				});
 	}
 
-	@CallSuper
-	@Override
-	public void onStart() {
-		super.onStart();
-		sharingController.onStart();
-		list.startPeriodicUpdate();
-	}
-
-	@CallSuper
-	@Override
-	public void onStop() {
-		super.onStop();
-		sharingController.onStop();
-		list.stopPeriodicUpdate();
-	}
-
-	@Override
-	protected void onSaveInstanceState(Bundle outState) {
-		super.onSaveInstanceState(outState);
-		if (replyId != null) {
-			outState.putByteArray(KEY_REPLY_ID, replyId.getBytes());
-		}
-	}
-
-	@Override
-	protected void onRestoreInstanceState(Bundle savedInstanceState) {
-		super.onRestoreInstanceState(savedInstanceState);
-	}
-
-	@Override
-	public boolean onOptionsItemSelected(MenuItem item) {
-		if (item.getItemId() == android.R.id.home) {
-			supportFinishAfterTransition();
-			return true;
-		}
-		return super.onOptionsItemSelected(item);
-	}
-
-	@Override
-	public void onBackPressed() {
-		if (adapter.getHighlightedItem() != null) {
-			textInput.clearText();
-			replyId = null;
-			updateTextInput();
-		} else {
-			super.onBackPressed();
-		}
-	}
-
 	@Override
 	public void onReplyClick(I item) {
-		replyId = item.getId();
+		getViewModel().setReplyId(item.getId());
 		updateTextInput();
 		// FIXME This does not work for a hardware keyboard
 		if (textInput.isKeyboardOpen()) {
@@ -300,6 +265,7 @@ public abstract class ThreadListActivity<I extends ThreadItem, A extends ThreadI
 	}
 
 	private void updateTextInput() {
+		MessageId replyId = getViewModel().getReplyId();
 		if (replyId != null) {
 			textInput.setHint(R.string.forum_message_reply_hint);
 			textInput.showSoftKeyboard();
@@ -318,20 +284,10 @@ public abstract class ThreadListActivity<I extends ThreadItem, A extends ThreadI
 		getViewModel().createAndStoreMessage(text, replyItem);
 		textInput.hideSoftKeyboard();
 		textInput.clearText();
-		replyId = null;
+		getViewModel().setReplyId(null);
 		updateTextInput();
 	}
 
 	protected abstract int getMaxTextLength();
 
-	@Override
-	public void onItemReceived(I item) {
-		getViewModel().addItem(item, false);
-	}
-
-	@Override
-	public void onGroupRemoved() {
-		supportFinishAfterTransition();
-	}
-
 }

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

@@ -4,14 +4,11 @@ import org.briarproject.bramble.api.contact.ContactId;
 import org.briarproject.bramble.api.db.DbException;
 import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
 import org.briarproject.bramble.api.sync.GroupId;
-import org.briarproject.bramble.api.sync.MessageId;
 import org.briarproject.briar.android.controller.ActivityLifecycleController;
 import org.briarproject.briar.android.controller.handler.ResultExceptionHandler;
 
 import java.util.Collection;
 
-import javax.annotation.Nullable;
-
 import androidx.annotation.UiThread;
 
 @NotNullByDefault
@@ -27,23 +24,9 @@ public interface ThreadListController<I extends ThreadItem>
 
 	void markItemsRead(Collection<I> items);
 
-	interface ThreadListListener<I> extends ThreadListDataSource {
-
-		@UiThread
-		void onItemReceived(I item);
-
-		@UiThread
-		void onGroupRemoved();
-
+	interface ThreadListListener<I> {
 		@UiThread
 		void onInvitationAccepted(ContactId c);
 	}
 
-	interface ThreadListDataSource {
-
-		@UiThread
-		@Nullable
-		MessageId getFirstVisibleMessageId();
-	}
-
 }

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

@@ -14,7 +14,6 @@ import org.briarproject.bramble.api.nullsafety.MethodsNotNullByDefault;
 import org.briarproject.bramble.api.nullsafety.ParametersNotNullByDefault;
 import org.briarproject.bramble.api.sync.GroupId;
 import org.briarproject.bramble.api.sync.MessageId;
-import org.briarproject.bramble.api.sync.event.GroupRemovedEvent;
 import org.briarproject.bramble.api.system.Clock;
 import org.briarproject.briar.android.controller.DbControllerImpl;
 import org.briarproject.briar.api.android.AndroidNotificationManager;
@@ -78,14 +77,12 @@ public abstract class ThreadListControllerImpl<I extends ThreadItem>
 	@CallSuper
 	@Override
 	public void onActivityStart() {
-		notificationManager.blockNotification(getGroupId());
 		eventBus.addListener(this);
 	}
 
 	@CallSuper
 	@Override
 	public void onActivityStop() {
-		notificationManager.unblockNotification(getGroupId());
 		eventBus.removeListener(this);
 	}
 
@@ -94,16 +91,8 @@ public abstract class ThreadListControllerImpl<I extends ThreadItem>
 
 	}
 
-	@CallSuper
 	@Override
 	public void eventOccurred(Event e) {
-		if (e instanceof GroupRemovedEvent) {
-			GroupRemovedEvent s = (GroupRemovedEvent) e;
-			if (s.getGroup().getId().equals(getGroupId())) {
-				LOG.info("Group removed");
-				listener.onGroupRemoved();
-			}
-		}
 	}
 
 	@Override

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

@@ -7,6 +7,7 @@ import org.briarproject.bramble.api.db.DatabaseExecutor;
 import org.briarproject.bramble.api.db.DbException;
 import org.briarproject.bramble.api.db.Transaction;
 import org.briarproject.bramble.api.db.TransactionManager;
+import org.briarproject.bramble.api.event.Event;
 import org.briarproject.bramble.api.event.EventBus;
 import org.briarproject.bramble.api.event.EventListener;
 import org.briarproject.bramble.api.identity.IdentityManager;
@@ -15,6 +16,7 @@ import org.briarproject.bramble.api.nullsafety.MethodsNotNullByDefault;
 import org.briarproject.bramble.api.nullsafety.ParametersNotNullByDefault;
 import org.briarproject.bramble.api.sync.GroupId;
 import org.briarproject.bramble.api.sync.MessageId;
+import org.briarproject.bramble.api.sync.event.GroupRemovedEvent;
 import org.briarproject.bramble.api.system.AndroidExecutor;
 import org.briarproject.bramble.api.system.Clock;
 import org.briarproject.briar.android.viewmodel.DbViewModel;
@@ -65,14 +67,18 @@ public abstract class ThreadListViewModel<I extends ThreadItem>
 
 	@DatabaseExecutor
 	private final MessageTree<I> messageTree = new MessageTreeImpl<>();
-	protected final Map<MessageId, String> textCache =
+	protected final Map<MessageId, String> textCache = // TODO still needed?
 			new ConcurrentHashMap<>();
 	private final MutableLiveData<LiveResult<List<I>>> items =
 			new MutableLiveData<>();
+	private final MutableLiveData<Boolean> groupRemoved =
+			new MutableLiveData<>();
 	private final AtomicReference<MessageId> scrollToItem =
 			new AtomicReference<>();
 
 	protected volatile GroupId groupId;
+	@Nullable
+	private MessageId replyId;
 	private final AtomicReference<MessageId> storedMessageId =
 			new AtomicReference<>();
 
@@ -114,6 +120,26 @@ public abstract class ThreadListViewModel<I extends ThreadItem>
 		loadItems();
 	}
 
+	public void blockNotifications() {
+		notificationManager.blockNotification(groupId);
+	}
+
+	public void unblockNotifications() {
+		notificationManager.unblockNotification(groupId);
+	}
+
+	@Override
+	@CallSuper
+	public void eventOccurred(Event e) {
+		if (e instanceof GroupRemovedEvent) {
+			GroupRemovedEvent s = (GroupRemovedEvent) e;
+			if (s.getGroup().getId().equals(groupId)) {
+				LOG.info("Group removed");
+				groupRemoved.setValue(true);
+			}
+		}
+	}
+
 	private void loadStoredMessageId() {
 		runOnDbThread(() -> {
 			try {
@@ -161,9 +187,24 @@ public abstract class ThreadListViewModel<I extends ThreadItem>
 		return messageTree.depthFirstOrder();
 	}
 
-	protected void addItem(I item, boolean local) {
+	/**
+	 * Add a remote item on the UI thread.
+	 * The list will not scroll, but show an unread indicator.
+	 */
+	@UiThread
+	protected void addItem(I item) {
 		messageTree.add(item);
-		if (local) scrollToItem.set(item.getId());
+		items.setValue(new LiveResult<>(messageTree.depthFirstOrder()));
+	}
+
+	/**
+	 * Add a local item from the DB thread.
+	 * The list will scroll to the new item.
+	 */
+	@DatabaseExecutor
+	protected void addItemAsync(I item) {
+		messageTree.add(item);
+		scrollToItem.set(item.getId());
 		items.postValue(new LiveResult<>(messageTree.depthFirstOrder()));
 	}
 
@@ -171,6 +212,17 @@ public abstract class ThreadListViewModel<I extends ThreadItem>
 	protected abstract String loadMessageText(Transaction txn,
 			PostHeader header) throws DbException;
 
+	@UiThread
+	public void setReplyId(@Nullable MessageId id) {
+		replyId = id;
+	}
+
+	@UiThread
+	@Nullable
+	public MessageId getReplyId() {
+		return replyId;
+	}
+
 	void storeMessageId(@Nullable MessageId messageId) {
 		if (messageId != null) runOnDbThread(() -> {
 			try {
@@ -190,6 +242,10 @@ public abstract class ThreadListViewModel<I extends ThreadItem>
 		return items;
 	}
 
+	LiveData<Boolean> getGroupRemoved() {
+		return groupRemoved;
+	}
+
 	@Nullable
 	MessageId getAndResetScrollToItem() {
 		return scrollToItem.getAndSet(null);