Introduce view model for ContactChooserFragment

Add GitLab pipeline stage for running optional tests

See merge request briar/briar!1353

.gitlab-ci.yml

@@ -2,6 +2,7 @@ image: briar/ci-image-android:latest
 
 stages:
 - test
+- optional_tests
 - check_reproducibility
 
 test:
@@ -31,3 +32,33 @@ test_reproducible:
     - "curl -X POST -F token=${RELEASE_CHECK_TOKEN} -F ref=master -F variables[RELEASE_TAG]=${CI_COMMIT_REF_NAME} https://code.briarproject.org/api/v4/projects/61/trigger/pipeline"
   only:
     - tags
+
+.optional_tests:
+  stage: optional_tests
+  before_script:
+    - set -e
+    - export GRADLE_USER_HOME=$PWD/.gradle
+
+  cache:
+    paths:
+      - .gradle/wrapper
+      - .gradle/caches
+
+  script:
+    - OPTIONAL_TESTS=org.briarproject.bramble.plugin.tor.BridgeTest ./gradlew --info bramble-java:test --tests BridgeTest
+
+  after_script:
+    # these file change every time but should not be cached
+    - rm -f $GRADLE_USER_HOME/caches/modules-2/modules-2.lock
+    - rm -fr $GRADLE_USER_HOME/caches/*/plugin-resolution/
+
+manual_tests:
+  extends: .optional_tests
+  when: manual
+  except:
+    - tags
+
+pre_release_tests:
+  extends: .optional_tests
+  only:
+    - tags

bramble-android/build.gradle

@@ -11,8 +11,8 @@ android {
 	defaultConfig {
 		minSdkVersion 16
 		targetSdkVersion 29
-		versionCode 10213
-		versionName "1.2.13"
+		versionCode 10214
+		versionName "1.2.14"
 		consumerProguardFiles 'proguard-rules.txt'
 
 		testInstrumentationRunner "androidx.test.runner.AndroidJUnitRunner"

bramble-java/src/test/java/org/briarproject/bramble/plugin/tor/BridgeTest.java

@@ -53,7 +53,7 @@ public class BridgeTest extends BrambleTestCase {
 		return component.getCircumventionProvider().getBridges(false);
 	}
 
-	private final static long TIMEOUT = SECONDS.toMillis(30);
+	private final static long TIMEOUT = SECONDS.toMillis(60);
 
 	private final static Logger LOG = getLogger(BridgeTest.class.getName());
 

briar-android/artwork/notification_signout.svg

@@ -0,0 +1 @@
+<?xml version="1.0" encoding="UTF-8"?><!DOCTYPE svg PUBLIC "-//W3C//DTD SVG 1.1//EN" "http://www.w3.org/Graphics/SVG/1.1/DTD/svg11.dtd"><svg xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink" version="1.1" width="24" height="24" viewBox="0 0 24 24"><path d="M16,17V14H9V10H16V7L21,12L16,17M14,2A2,2 0 0,1 16,4V6H14V4H5V20H14V18H16V20A2,2 0 0,1 14,22H5A2,2 0 0,1 3,20V4A2,2 0 0,1 5,2H14Z" /></svg>

briar-android/build.gradle

@@ -22,9 +22,11 @@ android {
 	defaultConfig {
 		minSdkVersion 16
 		targetSdkVersion 29
-		versionCode 10213
-		versionName "1.2.13"
+		versionCode 10214
+		versionName "1.2.14"
 		applicationId "org.briarproject.briar.android"
+
+		vectorDrawables.useSupportLibrary = true
 		buildConfigField "String", "GitHash",
 				"\"${getStdout(['git', 'rev-parse', '--short=7', 'HEAD'], 'No commit hash')}\""
 		def now = (long) (System.currentTimeMillis() / 1000)

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

@@ -255,7 +255,7 @@ class AndroidNotificationManagerImpl implements AndroidNotificationManager,
 				R.string.ongoing_notification_title;
 		int text = locked ? R.string.lock_tap_to_unlock :
 				R.string.ongoing_notification_text;
-		int icon = locked ? R.drawable.startup_lock :
+		int icon = locked ? R.drawable.notification_lock :
 				R.drawable.notification_ongoing;
 		// Ongoing foreground notification that shows BriarService is running
 		NotificationCompat.Builder b =
@@ -624,7 +624,7 @@ class AndroidNotificationManagerImpl implements AndroidNotificationManager,
 
 		NotificationCompat.Builder b =
 				new NotificationCompat.Builder(appContext, REMINDER_CHANNEL_ID);
-		b.setSmallIcon(R.drawable.ic_signout);
+		b.setSmallIcon(R.drawable.notification_signout);
 		b.setColor(getColor(appContext, R.color.briar_primary));
 		b.setContentTitle(
 				appContext.getText(R.string.reminder_notification_title));

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

@@ -32,12 +32,15 @@ import org.briarproject.briar.android.account.LockManagerImpl;
 import org.briarproject.briar.android.account.SetupModule;
 import org.briarproject.briar.android.contact.ContactListModule;
 import org.briarproject.briar.android.forum.ForumModule;
+import org.briarproject.briar.android.introduction.IntroductionModule;
 import org.briarproject.briar.android.keyagreement.ContactExchangeModule;
 import org.briarproject.briar.android.login.LoginModule;
 import org.briarproject.briar.android.navdrawer.NavDrawerModule;
-import org.briarproject.briar.android.settings.SettingsModule;
+import org.briarproject.briar.android.privategroup.conversation.GroupConversationModule;
 import org.briarproject.briar.android.privategroup.list.GroupListModule;
 import org.briarproject.briar.android.reporting.DevReportModule;
+import org.briarproject.briar.android.settings.SettingsModule;
+import org.briarproject.briar.android.sharing.SharingModule;
 import org.briarproject.briar.android.test.TestAvatarCreatorImpl;
 import org.briarproject.briar.android.viewmodel.ViewModelModule;
 import org.briarproject.briar.api.android.AndroidNotificationManager;
@@ -78,9 +81,12 @@ import static org.briarproject.briar.android.TestingConstants.IS_DEBUG_BUILD;
 		SettingsModule.class,
 		DevReportModule.class,
 		ContactListModule.class,
+		IntroductionModule.class,
 		// below need to be within same scope as ViewModelProvider.Factory
-		ForumModule.BindsModule.class,
+		ForumModule.class,
 		GroupListModule.class,
+		GroupConversationModule.class,
+		SharingModule.class,
 })
 public class AppModule {
 

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

@@ -32,7 +32,6 @@ import org.briarproject.briar.android.conversation.ImageFragment;
 import org.briarproject.briar.android.forum.CreateForumActivity;
 import org.briarproject.briar.android.forum.ForumActivity;
 import org.briarproject.briar.android.forum.ForumListFragment;
-import org.briarproject.briar.android.forum.ForumModule;
 import org.briarproject.briar.android.fragment.ScreenFilterDialogFragment;
 import org.briarproject.briar.android.introduction.ContactChooserFragment;
 import org.briarproject.briar.android.introduction.IntroductionActivity;
@@ -50,7 +49,6 @@ import org.briarproject.briar.android.navdrawer.TransportsActivity;
 import org.briarproject.briar.android.panic.PanicPreferencesActivity;
 import org.briarproject.briar.android.panic.PanicResponderActivity;
 import org.briarproject.briar.android.privategroup.conversation.GroupActivity;
-import org.briarproject.briar.android.privategroup.conversation.GroupConversationModule;
 import org.briarproject.briar.android.privategroup.creation.CreateGroupActivity;
 import org.briarproject.briar.android.privategroup.creation.CreateGroupFragment;
 import org.briarproject.briar.android.privategroup.creation.CreateGroupModule;
@@ -89,12 +87,10 @@ import dagger.Component;
 		ActivityModule.class,
 		BlogModule.class,
 		CreateGroupModule.class,
-		ForumModule.class,
 		GroupInvitationModule.class,
-		GroupConversationModule.class,
 		GroupMemberModule.class,
 		GroupRevealModule.class,
-		SharingModule.class
+		SharingModule.SharingLegacyModule.class
 }, dependencies = AndroidComponent.class)
 public interface ActivityComponent {
 

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

@@ -14,7 +14,6 @@ import org.briarproject.briar.android.BriarApplication;
 import org.briarproject.briar.android.DestroyableContext;
 import org.briarproject.briar.android.Localizer;
 import org.briarproject.briar.android.controller.ActivityLifecycleController;
-import org.briarproject.briar.android.forum.ForumModule;
 import org.briarproject.briar.android.fragment.BaseFragment;
 import org.briarproject.briar.android.fragment.ScreenFilterDialogFragment;
 import org.briarproject.briar.android.util.UiUtils;
@@ -87,7 +86,6 @@ public abstract class BaseActivity extends AppCompatActivity
 		activityComponent = DaggerActivityComponent.builder()
 				.androidComponent(applicationComponent)
 				.activityModule(getActivityModule())
-				.forumModule(getForumModule())
 				.build();
 		injectActivity(activityComponent);
 		super.onCreate(state);
@@ -122,11 +120,6 @@ public abstract class BaseActivity extends AppCompatActivity
 		return new ActivityModule(this);
 	}
 
-	// TODO use a test module where this is used in tests
-	protected ForumModule getForumModule() {
-		return new ForumModule();
-	}
-
 	@Override
 	protected void onStart() {
 		super.onStart();

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

@@ -160,7 +160,6 @@ public abstract class BriarActivity extends BaseActivity {
 	 * @param ownLayout true if the custom toolbar brings its own layout
 	 * @return the Toolbar object or null if content view did not contain one
 	 */
-	@Nullable
 	protected Toolbar setUpCustomToolbar(boolean ownLayout) {
 		// Custom Toolbar
 		Toolbar toolbar = findViewById(R.id.toolbar);

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

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

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

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

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

@@ -7,7 +7,6 @@ import android.view.ViewGroup;
 import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
 import org.briarproject.bramble.api.nullsafety.NullSafety;
 import org.briarproject.briar.R;
-import org.briarproject.briar.android.contact.BaseContactListAdapter.OnContactClickListener;
 
 import androidx.recyclerview.widget.DiffUtil.ItemCallback;
 import androidx.recyclerview.widget.ListAdapter;

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

@@ -15,7 +15,6 @@ import org.briarproject.bramble.api.nullsafety.MethodsNotNullByDefault;
 import org.briarproject.bramble.api.nullsafety.ParametersNotNullByDefault;
 import org.briarproject.briar.R;
 import org.briarproject.briar.android.activity.ActivityComponent;
-import org.briarproject.briar.android.contact.BaseContactListAdapter.OnContactClickListener;
 import org.briarproject.briar.android.contact.add.remote.AddContactActivity;
 import org.briarproject.briar.android.contact.add.remote.PendingContactListActivity;
 import org.briarproject.briar.android.conversation.ConversationActivity;
@@ -102,6 +101,8 @@ public class ContactListFragment extends BaseFragment
 				.observe(getViewLifecycleOwner(), result -> {
 					result.onError(this::handleException).onSuccess(items -> {
 						adapter.submitList(items);
+						// TODO: this should not be required any longer due to
+						//  changes in BriarRecyclerView
 						if (requireNonNull(items).size() == 0) list.showData();
 					});
 				});

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

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

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

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

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

@@ -0,0 +1,167 @@
+package org.briarproject.briar.android.contact;
+
+import android.app.Application;
+
+import org.briarproject.bramble.api.connection.ConnectionRegistry;
+import org.briarproject.bramble.api.contact.Contact;
+import org.briarproject.bramble.api.contact.ContactId;
+import org.briarproject.bramble.api.contact.ContactManager;
+import org.briarproject.bramble.api.contact.event.ContactAddedEvent;
+import org.briarproject.bramble.api.contact.event.ContactRemovedEvent;
+import org.briarproject.bramble.api.db.DatabaseExecutor;
+import org.briarproject.bramble.api.db.DbException;
+import org.briarproject.bramble.api.db.Transaction;
+import org.briarproject.bramble.api.db.TransactionManager;
+import org.briarproject.bramble.api.event.Event;
+import org.briarproject.bramble.api.event.EventBus;
+import org.briarproject.bramble.api.event.EventListener;
+import org.briarproject.bramble.api.lifecycle.LifecycleManager;
+import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
+import org.briarproject.bramble.api.plugin.event.ContactConnectedEvent;
+import org.briarproject.bramble.api.plugin.event.ContactDisconnectedEvent;
+import org.briarproject.bramble.api.system.AndroidExecutor;
+import org.briarproject.briar.android.viewmodel.DbViewModel;
+import org.briarproject.briar.android.viewmodel.LiveResult;
+import org.briarproject.briar.api.avatar.event.AvatarUpdatedEvent;
+import org.briarproject.briar.api.client.MessageTracker;
+import org.briarproject.briar.api.conversation.ConversationManager;
+import org.briarproject.briar.api.conversation.ConversationMessageHeader;
+import org.briarproject.briar.api.conversation.event.ConversationMessageReceivedEvent;
+import org.briarproject.briar.api.identity.AuthorInfo;
+import org.briarproject.briar.api.identity.AuthorManager;
+
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.List;
+import java.util.concurrent.Executor;
+import java.util.logging.Logger;
+
+import javax.inject.Inject;
+
+import androidx.arch.core.util.Function;
+import androidx.lifecycle.LiveData;
+import androidx.lifecycle.MutableLiveData;
+
+import static java.util.logging.Logger.getLogger;
+import static org.briarproject.bramble.util.LogUtils.logDuration;
+import static org.briarproject.bramble.util.LogUtils.now;
+
+@NotNullByDefault
+public class ContactsViewModel extends DbViewModel implements EventListener {
+
+	private static final Logger LOG =
+			getLogger(ContactsViewModel.class.getName());
+
+	protected final ContactManager contactManager;
+	private final AuthorManager authorManager;
+	private final ConversationManager conversationManager;
+	private final ConnectionRegistry connectionRegistry;
+	private final EventBus eventBus;
+
+	private final MutableLiveData<LiveResult<List<ContactListItem>>>
+			contactListItems = new MutableLiveData<>();
+
+	@Inject
+	public ContactsViewModel(Application application,
+			@DatabaseExecutor Executor dbExecutor,
+			LifecycleManager lifecycleManager, TransactionManager db,
+			AndroidExecutor androidExecutor, ContactManager contactManager,
+			AuthorManager authorManager,
+			ConversationManager conversationManager,
+			ConnectionRegistry connectionRegistry, EventBus eventBus) {
+		super(application, dbExecutor, lifecycleManager, db, androidExecutor);
+		this.contactManager = contactManager;
+		this.authorManager = authorManager;
+		this.conversationManager = conversationManager;
+		this.connectionRegistry = connectionRegistry;
+		this.eventBus = eventBus;
+		this.eventBus.addListener(this);
+	}
+
+	@Override
+	protected void onCleared() {
+		super.onCleared();
+		eventBus.removeListener(this);
+	}
+
+	public void loadContacts() {
+		loadList(this::loadContacts, contactListItems::setValue);
+	}
+
+	private List<ContactListItem> loadContacts(Transaction txn)
+			throws DbException {
+		long start = now();
+		List<ContactListItem> contacts = new ArrayList<>();
+		for (Contact c : contactManager.getContacts(txn)) {
+			ContactId id = c.getId();
+			if (!displayContact(id)) {
+				continue;
+			}
+			AuthorInfo authorInfo = authorManager.getAuthorInfo(txn, c);
+			MessageTracker.GroupCount count =
+					conversationManager.getGroupCount(txn, id);
+			boolean connected = connectionRegistry.isConnected(c.getId());
+			contacts.add(new ContactListItem(c, authorInfo, connected, count));
+		}
+		Collections.sort(contacts);
+		logDuration(LOG, "Full load", start);
+		return contacts;
+	}
+
+	/**
+	 * Override this method to display only a subset of contacts.
+	 */
+	protected boolean displayContact(ContactId contactId) {
+		return true;
+	}
+
+	@Override
+	public void eventOccurred(Event e) {
+		if (e instanceof ContactAddedEvent) {
+			LOG.info("Contact added, reloading");
+			loadContacts();
+		} else if (e instanceof ContactConnectedEvent) {
+			updateItem(((ContactConnectedEvent) e).getContactId(),
+					item -> new ContactListItem(item, true), false);
+		} else if (e instanceof ContactDisconnectedEvent) {
+			updateItem(((ContactDisconnectedEvent) e).getContactId(),
+					item -> new ContactListItem(item, false), false);
+		} else if (e instanceof ContactRemovedEvent) {
+			LOG.info("Contact removed, removing item");
+			removeItem(((ContactRemovedEvent) e).getContactId());
+		} else if (e instanceof ConversationMessageReceivedEvent) {
+			LOG.info("Conversation message received, updating item");
+			ConversationMessageReceivedEvent<?> p =
+					(ConversationMessageReceivedEvent<?>) e;
+			ConversationMessageHeader h = p.getMessageHeader();
+			updateItem(p.getContactId(), item -> new ContactListItem(item, h),
+					true);
+		} else if (e instanceof AvatarUpdatedEvent) {
+			AvatarUpdatedEvent a = (AvatarUpdatedEvent) e;
+			updateItem(a.getContactId(), item -> new ContactListItem(item,
+					a.getAttachmentHeader()), false);
+		}
+	}
+
+	public LiveData<LiveResult<List<ContactListItem>>> getContactListItems() {
+		return contactListItems;
+	}
+
+	private void updateItem(ContactId c,
+			Function<ContactListItem, ContactListItem> replacer, boolean sort) {
+		List<ContactListItem> list = updateListItems(contactListItems,
+				itemToTest -> itemToTest.getContact().getId().equals(c),
+				replacer);
+		if (list == null) return;
+		if (sort) Collections.sort(list);
+		contactListItems.setValue(new LiveResult<>(list));
+	}
+
+	private void removeItem(ContactId c) {
+		List<ContactListItem> list = removeListItems(contactListItems,
+				itemToTest -> itemToTest.getContact().getId().equals(c));
+		if (list == null) return;
+		contactListItems.setValue(new LiveResult<>(list));
+	}
+
+}

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

@@ -1,50 +0,0 @@
-package org.briarproject.briar.android.contact;
-
-import android.content.Context;
-import android.view.LayoutInflater;
-import android.view.View;
-import android.view.ViewGroup;
-
-import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
-import org.briarproject.briar.R;
-
-@NotNullByDefault
-public class LegacyContactListAdapter extends
-		BaseContactListAdapter<ContactListItem, ContactListItemViewHolder> {
-
-	public LegacyContactListAdapter(Context context,
-			OnContactClickListener<ContactListItem> listener) {
-		super(context, ContactListItem.class, listener);
-	}
-
-	@Override
-	public ContactListItemViewHolder onCreateViewHolder(ViewGroup viewGroup,
-			int i) {
-		View v = LayoutInflater.from(viewGroup.getContext()).inflate(
-				R.layout.list_item_contact, viewGroup, false);
-
-		return new ContactListItemViewHolder(v);
-	}
-
-	@Override
-	public boolean areContentsTheSame(ContactListItem c1, ContactListItem c2) {
-		// check for all properties that influence visual
-		// representation of contact
-		if (c1.isEmpty() != c2.isEmpty()) {
-			return false;
-		}
-		if (c1.getUnreadCount() != c2.getUnreadCount()) {
-			return false;
-		}
-		if (c1.getTimestamp() != c2.getTimestamp()) {
-			return false;
-		}
-		return c1.isConnected() == c2.isConnected();
-	}
-
-	@Override
-	public int compare(ContactListItem c1, ContactListItem c2) {
-		return Long.compare(c2.getTimestamp(), c1.getTimestamp());
-	}
-
-}

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

@@ -7,6 +7,7 @@ import java.util.Collection;
 
 import androidx.annotation.UiThread;
 
+@Deprecated
 @NotNullByDefault
 public interface SharingController {
 

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

@@ -18,6 +18,7 @@ import javax.inject.Inject;
 
 import androidx.annotation.UiThread;
 
+@Deprecated
 @NotNullByDefault
 public class SharingControllerImpl implements SharingController, EventListener {
 

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

@@ -3,6 +3,7 @@ package org.briarproject.briar.android.conversation;
 import android.annotation.SuppressLint;
 import android.content.DialogInterface;
 import android.content.Intent;
+import android.graphics.drawable.Drawable;
 import android.os.Bundle;
 import android.os.Parcelable;
 import android.transition.Slide;
@@ -105,6 +106,7 @@ import androidx.recyclerview.selection.SelectionTracker.SelectionObserver;
 import androidx.recyclerview.selection.StorageStrategy;
 import androidx.recyclerview.widget.LinearLayoutManager;
 import androidx.recyclerview.widget.RecyclerView;
+import androidx.vectordrawable.graphics.drawable.VectorDrawableCompat;
 import de.hdodenhof.circleimageview.CircleImageView;
 import uk.co.samuelwall.materialtaptargetprompt.MaterialTapTargetPrompt;
 
@@ -479,12 +481,10 @@ public class ConversationActivity extends BriarActivity
 	@UiThread
 	private void displayContactOnlineStatus() {
 		if (connectionRegistry.isConnected(contactId)) {
-			toolbarStatus.setImageDrawable(ContextCompat.getDrawable(
-					ConversationActivity.this, R.drawable.contact_online));
+			toolbarStatus.setImageResource(R.drawable.contact_online);
 			toolbarStatus.setContentDescription(getString(R.string.online));
 		} else {
-			toolbarStatus.setImageDrawable(ContextCompat.getDrawable(
-					ConversationActivity.this, R.drawable.contact_offline));
+			toolbarStatus.setImageResource(R.drawable.contact_offline);
 			toolbarStatus.setContentDescription(getString(R.string.offline));
 		}
 	}
@@ -935,13 +935,16 @@ public class ConversationActivity extends BriarActivity
 			return;
 		}
 
+		int color =
+				ContextCompat.getColor(this, R.color.briar_primary);
+		Drawable drawable = VectorDrawableCompat
+				.create(getResources(), R.drawable.ic_more_vert_accent, null);
 		new MaterialTapTargetPrompt.Builder(ConversationActivity.this,
 				R.style.OnboardingDialogTheme).setTarget(target)
 				.setPrimaryText(R.string.introduction_onboarding_title)
 				.setSecondaryText(R.string.introduction_onboarding_text)
-				.setIcon(R.drawable.ic_more_vert_accent)
-				.setBackgroundColour(
-						ContextCompat.getColor(this, R.color.briar_primary))
+				.setIconDrawable(drawable)
+				.setBackgroundColour(color)
 				.show();
 	}
 

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

@@ -6,52 +6,54 @@ import android.os.Bundle;
 import android.view.Menu;
 import android.view.MenuInflater;
 import android.view.MenuItem;
-import android.widget.Toast;
 
-import org.briarproject.bramble.api.contact.ContactId;
-import org.briarproject.bramble.api.db.DbException;
 import org.briarproject.bramble.api.nullsafety.MethodsNotNullByDefault;
 import org.briarproject.bramble.api.nullsafety.ParametersNotNullByDefault;
 import org.briarproject.briar.R;
 import org.briarproject.briar.android.activity.ActivityComponent;
-import org.briarproject.briar.android.controller.handler.UiResultExceptionHandler;
-import org.briarproject.briar.android.forum.ForumController.ForumListener;
 import org.briarproject.briar.android.sharing.ForumSharingStatusActivity;
 import org.briarproject.briar.android.sharing.ShareForumActivity;
 import org.briarproject.briar.android.threaded.ThreadItemAdapter;
 import org.briarproject.briar.android.threaded.ThreadListActivity;
-import org.briarproject.briar.android.threaded.ThreadListController;
-import org.briarproject.briar.api.forum.Forum;
+import org.briarproject.briar.android.threaded.ThreadListViewModel;
 
 import javax.annotation.Nullable;
 import javax.inject.Inject;
 
 import androidx.appcompat.app.AlertDialog;
 import androidx.appcompat.widget.Toolbar;
-import androidx.recyclerview.widget.LinearLayoutManager;
+import androidx.lifecycle.ViewModelProvider;
 
 import static android.content.Intent.FLAG_ACTIVITY_CLEAR_TOP;
-import static android.widget.Toast.LENGTH_SHORT;
 import static org.briarproject.briar.android.activity.RequestCodes.REQUEST_SHARE_FORUM;
+import static org.briarproject.briar.android.util.UiUtils.observeOnce;
 import static org.briarproject.briar.api.forum.ForumConstants.MAX_FORUM_POST_TEXT_LENGTH;
 
 @MethodsNotNullByDefault
 @ParametersNotNullByDefault
 public class ForumActivity extends
-		ThreadListActivity<Forum, ForumPostItem, ThreadItemAdapter<ForumPostItem>>
-		implements ForumListener {
+		ThreadListActivity<ForumPostItem, ThreadItemAdapter<ForumPostItem>> {
 
 	@Inject
-	ForumController forumController;
+	ViewModelProvider.Factory viewModelFactory;
+
+	private ForumViewModel viewModel;
 
 	@Override
 	public void injectActivity(ActivityComponent component) {
 		component.inject(this);
+		viewModel = new ViewModelProvider(this, viewModelFactory)
+				.get(ForumViewModel.class);
 	}
 
 	@Override
-	protected ThreadListController<Forum, ForumPostItem> getController() {
-		return forumController;
+	protected ThreadListViewModel<ForumPostItem> getViewModel() {
+		return viewModel;
+	}
+
+	@Override
+	protected ThreadItemAdapter<ForumPostItem> createAdapter() {
+		return new ThreadItemAdapter<>(this);
 	}
 
 	@Override
@@ -59,36 +61,27 @@ public class ForumActivity extends
 		super.onCreate(state);
 
 		Toolbar toolbar = setUpCustomToolbar(false);
-
-		Intent i = getIntent();
-		String groupName = i.getStringExtra(GROUP_NAME);
-		if (groupName != null) setTitle(groupName);
-		else loadNamedGroup();
-
 		// Open member list on Toolbar click
-		if (toolbar != null) {
-			toolbar.setOnClickListener(v -> {
-				Intent i1 = new Intent(ForumActivity.this,
-						ForumSharingStatusActivity.class);
-				i1.putExtra(GROUP_ID, groupId.getBytes());
-				startActivity(i1);
-			});
+		toolbar.setOnClickListener(v -> {
+			Intent i = new Intent(ForumActivity.this,
+					ForumSharingStatusActivity.class);
+			i.putExtra(GROUP_ID, groupId.getBytes());
+			startActivity(i);
+		});
+
+		String groupName = getIntent().getStringExtra(GROUP_NAME);
+		if (groupName != null) {
+			setTitle(groupName);
+		} else {
+			observeOnce(viewModel.loadForum(), this, forum ->
+					setTitle(forum.getName())
+			);
 		}
 	}
 
 	@Override
-	protected void onNamedGroupLoaded(Forum forum) {
-		setTitle(forum.getName());
-	}
-
-	@Override
-	protected ThreadItemAdapter<ForumPostItem> createAdapter(
-			LinearLayoutManager layoutManager) {
-		return new ThreadItemAdapter<>(this, layoutManager);
-	}
-
-	@Override
-	protected void onActivityResult(int request, int result, Intent data) {
+	protected void onActivityResult(int request, int result,
+			@Nullable Intent data) {
 		super.onActivityResult(request, result, data);
 
 		if (request == REQUEST_SHARE_FORUM && result == RESULT_OK) {
@@ -101,32 +94,31 @@ public class ForumActivity extends
 		// Inflate the menu items for use in the action bar
 		MenuInflater inflater = getMenuInflater();
 		inflater.inflate(R.menu.forum_actions, menu);
-
-		return super.onCreateOptionsMenu(menu);
+		super.onCreateOptionsMenu(menu);
+		return true;
 	}
 
 	@Override
 	public boolean onOptionsItemSelected(MenuItem item) {
 		// Handle presses on the action bar items
-		switch (item.getItemId()) {
-			case R.id.action_forum_share:
-				Intent i2 = new Intent(this, ShareForumActivity.class);
-				i2.setFlags(FLAG_ACTIVITY_CLEAR_TOP);
-				i2.putExtra(GROUP_ID, groupId.getBytes());
-				startActivityForResult(i2, REQUEST_SHARE_FORUM);
-				return true;
-			case R.id.action_forum_sharing_status:
-				Intent i3 = new Intent(this, ForumSharingStatusActivity.class);
-				i3.setFlags(FLAG_ACTIVITY_CLEAR_TOP);
-				i3.putExtra(GROUP_ID, groupId.getBytes());
-				startActivity(i3);
-				return true;
-			case R.id.action_forum_delete:
-				showUnsubscribeDialog();
-				return true;
-			default:
-				return super.onOptionsItemSelected(item);
+		int itemId = item.getItemId();
+		if (itemId == R.id.action_forum_share) {
+			Intent i = new Intent(this, ShareForumActivity.class);
+			i.setFlags(FLAG_ACTIVITY_CLEAR_TOP);
+			i.putExtra(GROUP_ID, groupId.getBytes());
+			startActivityForResult(i, REQUEST_SHARE_FORUM);
+			return true;
+		} else if (itemId == R.id.action_forum_sharing_status) {
+			Intent i = new Intent(this, ForumSharingStatusActivity.class);
+			i.setFlags(FLAG_ACTIVITY_CLEAR_TOP);
+			i.putExtra(GROUP_ID, groupId.getBytes());
+			startActivity(i);
+			return true;
+		} else if (itemId == R.id.action_forum_delete) {
+			showUnsubscribeDialog();
+			return true;
 		}
+		return super.onOptionsItemSelected(item);
 	}
 
 	@Override
@@ -135,7 +127,7 @@ public class ForumActivity extends
 	}
 
 	private void showUnsubscribeDialog() {
-		OnClickListener okListener = (dialog, which) -> deleteForum();
+		OnClickListener okListener = (dialog, which) -> viewModel.deleteForum();
 		AlertDialog.Builder builder = new AlertDialog.Builder(this,
 				R.style.BriarDialogTheme);
 		builder.setTitle(getString(R.string.dialog_title_leave_forum));
@@ -145,27 +137,4 @@ public class ForumActivity extends
 		builder.show();
 	}
 
-	private void deleteForum() {
-		forumController.deleteNamedGroup(
-				new UiResultExceptionHandler<Void, DbException>(this) {
-					@Override
-					public void onResultUi(Void v) {
-						Toast.makeText(ForumActivity.this,
-								R.string.forum_left_toast, LENGTH_SHORT).show();
-					}
-
-					@Override
-					public void onExceptionUi(DbException exception) {
-						handleException(exception);
-					}
-				});
-	}
-
-	@Override
-	public void onForumLeft(ContactId c) {
-		sharingController.remove(c);
-		setToolbarSubTitle(sharingController.getTotalCount(),
-				sharingController.getOnlineCount());
-	}
-
 }

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

@@ -1,18 +0,0 @@
-package org.briarproject.briar.android.forum;
-
-import org.briarproject.bramble.api.contact.ContactId;
-import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
-import org.briarproject.briar.android.threaded.ThreadListController;
-import org.briarproject.briar.api.forum.Forum;
-
-import androidx.annotation.UiThread;
-
-@NotNullByDefault
-interface ForumController extends ThreadListController<Forum, ForumPostItem> {
-
-	interface ForumListener extends ThreadListListener<ForumPostItem> {
-		@UiThread
-		void onForumLeft(ContactId c);
-	}
-
-}

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

@@ -1,185 +0,0 @@
-package org.briarproject.briar.android.forum;
-
-import org.briarproject.bramble.api.contact.Contact;
-import org.briarproject.bramble.api.contact.ContactId;
-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.event.Event;
-import org.briarproject.bramble.api.event.EventBus;
-import org.briarproject.bramble.api.identity.IdentityManager;
-import org.briarproject.bramble.api.identity.LocalAuthor;
-import org.briarproject.bramble.api.lifecycle.LifecycleManager;
-import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
-import org.briarproject.bramble.api.sync.MessageId;
-import org.briarproject.bramble.api.system.Clock;
-import org.briarproject.briar.android.controller.handler.ResultExceptionHandler;
-import org.briarproject.briar.android.forum.ForumController.ForumListener;
-import org.briarproject.briar.android.threaded.ThreadListControllerImpl;
-import org.briarproject.briar.api.android.AndroidNotificationManager;
-import org.briarproject.briar.api.client.MessageTracker;
-import org.briarproject.briar.api.client.MessageTracker.GroupCount;
-import org.briarproject.briar.api.forum.Forum;
-import org.briarproject.briar.api.forum.ForumInvitationResponse;
-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.ForumInvitationResponseReceivedEvent;
-import org.briarproject.briar.api.forum.event.ForumPostReceivedEvent;
-import org.briarproject.briar.api.sharing.event.ContactLeftShareableEvent;
-
-import java.util.ArrayList;
-import java.util.Collection;
-import java.util.concurrent.Executor;
-import java.util.logging.Logger;
-
-import javax.annotation.Nullable;
-import javax.inject.Inject;
-
-import static java.lang.Math.max;
-import static java.util.logging.Level.WARNING;
-import static org.briarproject.bramble.util.LogUtils.logException;
-
-@NotNullByDefault
-class ForumControllerImpl extends
-		ThreadListControllerImpl<Forum, ForumPostItem, ForumPostHeader, ForumPost, ForumListener>
-		implements ForumController {
-
-	private static final Logger LOG =
-			Logger.getLogger(ForumControllerImpl.class.getName());
-
-	private final ForumManager forumManager;
-	private final ForumSharingManager forumSharingManager;
-
-	@Inject
-	ForumControllerImpl(@DatabaseExecutor Executor dbExecutor,
-			LifecycleManager lifecycleManager, IdentityManager identityManager,
-			@CryptoExecutor Executor cryptoExecutor,
-			ForumManager forumManager, ForumSharingManager forumSharingManager,
-			EventBus eventBus, Clock clock, MessageTracker messageTracker,
-			AndroidNotificationManager notificationManager) {
-		super(dbExecutor, lifecycleManager, identityManager, cryptoExecutor,
-				eventBus, clock, notificationManager, messageTracker);
-		this.forumManager = forumManager;
-		this.forumSharingManager = forumSharingManager;
-	}
-
-	@Override
-	public void onActivityStart() {
-		super.onActivityStart();
-		notificationManager.clearForumPostNotification(getGroupId());
-	}
-
-	@Override
-	public void eventOccurred(Event e) {
-		super.eventOccurred(e);
-
-		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) {
-			ForumInvitationResponseReceivedEvent f =
-					(ForumInvitationResponseReceivedEvent) e;
-			ForumInvitationResponse r = f.getMessageHeader();
-			if (r.getShareableId().equals(getGroupId()) && r.wasAccepted()) {
-				LOG.info("Forum invitation was accepted");
-				listener.onInvitationAccepted(f.getContactId());
-			}
-		} else if (e instanceof ContactLeftShareableEvent) {
-			ContactLeftShareableEvent c = (ContactLeftShareableEvent) e;
-			if (c.getGroupId().equals(getGroupId())) {
-				LOG.info("Forum left by contact");
-				listener.onForumLeft(c.getContactId());
-			}
-		}
-	}
-
-	@Override
-	protected Forum loadNamedGroup() throws DbException {
-		return forumManager.getForum(getGroupId());
-	}
-
-	@Override
-	protected Collection<ForumPostHeader> loadHeaders() throws DbException {
-		return forumManager.getPostHeaders(getGroupId());
-	}
-
-	@Override
-	protected String loadMessageText(ForumPostHeader h) throws DbException {
-		return forumManager.getPostText(h.getId());
-	}
-
-	@Override
-	protected void markRead(MessageId id) throws DbException {
-		forumManager.setReadFlag(getGroupId(), id, true);
-	}
-
-	@Override
-	public void loadSharingContacts(
-			ResultExceptionHandler<Collection<ContactId>, DbException> handler) {
-		runOnDbThread(() -> {
-			try {
-				Collection<Contact> contacts =
-						forumSharingManager.getSharedWith(getGroupId());
-				Collection<ContactId> contactIds =
-						new ArrayList<>(contacts.size());
-				for (Contact c : contacts) contactIds.add(c.getId());
-				handler.onResult(contactIds);
-			} catch (DbException e) {
-				logException(LOG, WARNING, e);
-				handler.onException(e);
-			}
-		});
-	}
-
-	@Override
-	public void createAndStoreMessage(String text,
-			@Nullable ForumPostItem parentItem,
-			ResultExceptionHandler<ForumPostItem, DbException> handler) {
-		runOnDbThread(() -> {
-			try {
-				LocalAuthor author = identityManager.getLocalAuthor();
-				GroupCount count = forumManager.getGroupCount(getGroupId());
-				long timestamp = max(count.getLatestMsgTime() + 1,
-						clock.currentTimeMillis());
-				MessageId parentId = parentItem != null ?
-						parentItem.getId() : null;
-				createMessage(text, timestamp, parentId, author, handler);
-			} catch (DbException e) {
-				logException(LOG, WARNING, e);
-				handler.onException(e);
-			}
-		});
-	}
-
-	private void createMessage(String text, long timestamp,
-			@Nullable MessageId parentId, LocalAuthor author,
-			ResultExceptionHandler<ForumPostItem, DbException> handler) {
-		cryptoExecutor.execute(() -> {
-			LOG.info("Creating forum post...");
-			ForumPost msg = forumManager.createLocalPost(getGroupId(), text,
-					timestamp, parentId, author);
-			storePost(msg, text, handler);
-		});
-	}
-
-	@Override
-	protected ForumPostHeader addLocalMessage(ForumPost p) throws DbException {
-		return forumManager.addLocalPost(p);
-	}
-
-	@Override
-	protected void deleteNamedGroup(Forum forum) throws DbException {
-		forumManager.removeForum(forum);
-	}
-
-	@Override
-	protected ForumPostItem buildItem(ForumPostHeader header, String text) {
-		return new ForumPostItem(header, text);
-	}
-
-}

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

@@ -1,32 +1,23 @@
 package org.briarproject.briar.android.forum;
 
-import org.briarproject.briar.android.activity.ActivityScope;
-import org.briarproject.briar.android.activity.BaseActivity;
 import org.briarproject.briar.android.viewmodel.ViewModelKey;
 
 import androidx.lifecycle.ViewModel;
 import dagger.Binds;
 import dagger.Module;
-import dagger.Provides;
 import dagger.multibindings.IntoMap;
 
 @Module
-public class ForumModule {
+public interface ForumModule {
 
-	@Module
-	public interface BindsModule {
-		@Binds
-		@IntoMap
-		@ViewModelKey(ForumListViewModel.class)
-		ViewModel bindForumListViewModel(ForumListViewModel forumListViewModel);
-	}
+	@Binds
+	@IntoMap
+	@ViewModelKey(ForumListViewModel.class)
+	ViewModel bindForumListViewModel(ForumListViewModel forumListViewModel);
 
-	@ActivityScope
-	@Provides
-	ForumController provideForumController(BaseActivity activity,
-			ForumControllerImpl forumController) {
-		activity.addLifecycleController(forumController);
-		return forumController;
-	}
+	@Binds
+	@IntoMap
+	@ViewModelKey(ForumViewModel.class)
+	ViewModel bindForumViewModel(ForumViewModel forumViewModel);
 
 }

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

@@ -6,7 +6,6 @@ import org.briarproject.bramble.api.sync.MessageId;
 import org.briarproject.briar.android.threaded.ThreadItem;
 import org.briarproject.briar.api.forum.ForumPostHeader;
 
-import javax.annotation.Nullable;
 import javax.annotation.concurrent.NotThreadSafe;
 
 @NotThreadSafe
@@ -17,9 +16,4 @@ class ForumPostItem extends ThreadItem {
 				h.getAuthorInfo(), h.isRead());
 	}
 
-	ForumPostItem(MessageId messageId, @Nullable MessageId parentId,
-			String text, long timestamp, Author author, AuthorInfo authorInfo) {
-		super(messageId, parentId, text, timestamp, author, authorInfo, true);
-	}
-
 }

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

@@ -0,0 +1,231 @@
+package org.briarproject.briar.android.forum;
+
+import android.app.Application;
+import android.widget.Toast;
+
+import org.briarproject.bramble.api.contact.Contact;
+import org.briarproject.bramble.api.contact.ContactId;
+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.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.identity.IdentityManager;
+import org.briarproject.bramble.api.identity.LocalAuthor;
+import org.briarproject.bramble.api.lifecycle.LifecycleManager;
+import org.briarproject.bramble.api.nullsafety.MethodsNotNullByDefault;
+import org.briarproject.bramble.api.nullsafety.ParametersNotNullByDefault;
+import org.briarproject.bramble.api.sync.MessageId;
+import org.briarproject.bramble.api.system.AndroidExecutor;
+import org.briarproject.bramble.api.system.Clock;
+import org.briarproject.briar.R;
+import org.briarproject.briar.android.sharing.SharingController;
+import org.briarproject.briar.android.threaded.ThreadListViewModel;
+import org.briarproject.briar.api.android.AndroidNotificationManager;
+import org.briarproject.briar.api.client.MessageTracker;
+import org.briarproject.briar.api.client.MessageTracker.GroupCount;
+import org.briarproject.briar.api.forum.Forum;
+import org.briarproject.briar.api.forum.ForumInvitationResponse;
+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.ForumInvitationResponseReceivedEvent;
+import org.briarproject.briar.api.forum.event.ForumPostReceivedEvent;
+import org.briarproject.briar.api.sharing.event.ContactLeftShareableEvent;
+
+import java.util.ArrayList;
+import java.util.Collection;
+import java.util.List;
+import java.util.concurrent.Executor;
+import java.util.logging.Logger;
+
+import javax.annotation.Nullable;
+import javax.inject.Inject;
+
+import androidx.lifecycle.LiveData;
+import androidx.lifecycle.MutableLiveData;
+
+import static android.widget.Toast.LENGTH_SHORT;
+import static java.lang.Math.max;
+import static java.util.logging.Level.WARNING;
+import static java.util.logging.Logger.getLogger;
+import static org.briarproject.bramble.util.LogUtils.logDuration;
+import static org.briarproject.bramble.util.LogUtils.logException;
+import static org.briarproject.bramble.util.LogUtils.now;
+
+@MethodsNotNullByDefault
+@ParametersNotNullByDefault
+class ForumViewModel extends ThreadListViewModel<ForumPostItem> {
+
+	private static final Logger LOG = getLogger(ForumViewModel.class.getName());
+
+	private final ForumManager forumManager;
+	private final ForumSharingManager forumSharingManager;
+
+	@Inject
+	ForumViewModel(Application application,
+			@DatabaseExecutor Executor dbExecutor,
+			LifecycleManager lifecycleManager,
+			TransactionManager db,
+			AndroidExecutor androidExecutor,
+			IdentityManager identityManager,
+			AndroidNotificationManager notificationManager,
+			SharingController sharingController,
+			@CryptoExecutor Executor cryptoExecutor,
+			Clock clock,
+			MessageTracker messageTracker,
+			EventBus eventBus,
+			ForumManager forumManager,
+			ForumSharingManager forumSharingManager) {
+		super(application, dbExecutor, lifecycleManager, db, androidExecutor,
+				identityManager, notificationManager, sharingController,
+				cryptoExecutor, clock, messageTracker, eventBus);
+		this.forumManager = forumManager;
+		this.forumSharingManager = forumSharingManager;
+	}
+
+	@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 =
+						new ForumPostItem(f.getHeader(), f.getText());
+				addItem(item, false);
+			}
+		} else if (e instanceof ForumInvitationResponseReceivedEvent) {
+			ForumInvitationResponseReceivedEvent f =
+					(ForumInvitationResponseReceivedEvent) e;
+			ForumInvitationResponse r = f.getMessageHeader();
+			if (r.getShareableId().equals(groupId) && r.wasAccepted()) {
+				LOG.info("Forum invitation was accepted");
+				sharingController.add(f.getContactId());
+			}
+		} else if (e instanceof ContactLeftShareableEvent) {
+			ContactLeftShareableEvent c = (ContactLeftShareableEvent) e;
+			if (c.getGroupId().equals(groupId)) {
+				LOG.info("Forum left by contact");
+				sharingController.remove(c.getContactId());
+			}
+		} else {
+			super.eventOccurred(e);
+		}
+	}
+
+	protected void clearNotifications() {
+		notificationManager.clearForumPostNotification(groupId);
+	}
+
+	LiveData<Forum> loadForum() {
+		MutableLiveData<Forum> forum = new MutableLiveData<>();
+		runOnDbThread(() -> {
+			try {
+				Forum f = forumManager.getForum(groupId);
+				forum.postValue(f);
+			} catch (DbException e) {
+				logException(LOG, WARNING, e);
+			}
+		});
+		return forum;
+	}
+
+	@Override
+	public void loadItems() {
+		loadList(txn -> {
+			long start = now();
+			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));
+			}
+			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) {
+		runOnDbThread(() -> {
+			try {
+				LocalAuthor author = identityManager.getLocalAuthor();
+				GroupCount count = forumManager.getGroupCount(groupId);
+				long timestamp = max(count.getLatestMsgTime() + 1,
+						clock.currentTimeMillis());
+				createMessage(text, timestamp, parentId, author);
+			} catch (DbException e) {
+				logException(LOG, WARNING, e);
+			}
+		});
+	}
+
+	private void createMessage(String text, long timestamp,
+			@Nullable MessageId parentId, LocalAuthor author) {
+		cryptoExecutor.execute(() -> {
+			LOG.info("Creating forum post...");
+			ForumPost msg = forumManager.createLocalPost(groupId, text,
+					timestamp, parentId, author);
+			storePost(msg, text);
+		});
+	}
+
+	private void storePost(ForumPost msg, String text) {
+		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);
+			});
+		}, e -> logException(LOG, WARNING, e));
+	}
+
+	@Override
+	protected void markItemRead(ForumPostItem item) {
+		runOnDbThread(() -> {
+			try {
+				forumManager.setReadFlag(groupId, item.getId(), true);
+			} catch (DbException e) {
+				logException(LOG, WARNING, e);
+			}
+		});
+	}
+
+	public void loadSharingContacts() {
+		runOnDbThread(true, txn -> {
+			Collection<Contact> contacts =
+					forumSharingManager.getSharedWith(txn, groupId);
+			Collection<ContactId> contactIds = new ArrayList<>(contacts.size());
+			for (Contact c : contacts) contactIds.add(c.getId());
+			txn.attach(() -> sharingController.addAll(contactIds));
+		}, e -> logException(LOG, WARNING, e));
+	}
+
+	void deleteForum() {
+		runOnDbThread(() -> {
+			try {
+				Forum f = forumManager.getForum(groupId);
+				forumManager.removeForum(f);
+			} catch (DbException e) {
+				logException(LOG, WARNING, e);
+			}
+		});
+		Toast.makeText(getApplication(), R.string.forum_left_toast,
+				LENGTH_SHORT).show();
+	}
+
+}

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

@@ -5,63 +5,42 @@ import android.view.LayoutInflater;
 import android.view.View;
 import android.view.ViewGroup;
 
-import org.briarproject.bramble.api.connection.ConnectionRegistry;
 import org.briarproject.bramble.api.contact.Contact;
 import org.briarproject.bramble.api.contact.ContactId;
-import org.briarproject.bramble.api.contact.ContactManager;
-import org.briarproject.bramble.api.db.DbException;
 import org.briarproject.bramble.api.nullsafety.MethodsNotNullByDefault;
 import org.briarproject.bramble.api.nullsafety.ParametersNotNullByDefault;
 import org.briarproject.briar.R;
 import org.briarproject.briar.android.activity.ActivityComponent;
-import org.briarproject.briar.android.contact.BaseContactListAdapter.OnContactClickListener;
+import org.briarproject.briar.android.contact.ContactListAdapter;
 import org.briarproject.briar.android.contact.ContactListItem;
-import org.briarproject.briar.android.contact.LegacyContactListAdapter;
+import org.briarproject.briar.android.contact.OnContactClickListener;
 import org.briarproject.briar.android.fragment.BaseFragment;
 import org.briarproject.briar.android.view.BriarRecyclerView;
-import org.briarproject.briar.api.client.MessageTracker.GroupCount;
-import org.briarproject.briar.api.conversation.ConversationManager;
-import org.briarproject.briar.api.identity.AuthorInfo;
-import org.briarproject.briar.api.identity.AuthorManager;
-
-import java.util.ArrayList;
-import java.util.List;
-import java.util.logging.Logger;
 
 import javax.inject.Inject;
 
 import androidx.annotation.Nullable;
-import androidx.annotation.UiThread;
+import androidx.lifecycle.ViewModelProvider;
 import androidx.recyclerview.widget.LinearLayoutManager;
 
-import static java.util.logging.Level.WARNING;
-import static org.briarproject.bramble.util.LogUtils.logException;
 import static org.briarproject.briar.android.conversation.ConversationActivity.CONTACT_ID;
 
-@UiThread
 @MethodsNotNullByDefault
 @ParametersNotNullByDefault
-public class ContactChooserFragment extends BaseFragment {
+public class ContactChooserFragment extends BaseFragment
+		implements OnContactClickListener<ContactListItem> {
 
-	public static final String TAG = ContactChooserFragment.class.getName();
-	private static final Logger LOG = Logger.getLogger(TAG);
+	private static final String TAG = ContactChooserFragment.class.getName();
 
+	@Inject
+	ViewModelProvider.Factory viewModelFactory;
+
+	private ContactListViewModel viewModel;
+	private final ContactListAdapter adapter = new ContactListAdapter(this);
 	private BriarRecyclerView list;
-	private LegacyContactListAdapter adapter;
 	private ContactId contactId;
 
-	// Fields that are accessed from background threads must be volatile
-	private volatile Contact c1;
-	@Inject
-	volatile ContactManager contactManager;
-	@Inject
-	volatile AuthorManager authorManager;
-	@Inject
-	volatile ConversationManager conversationManager;
-	@Inject
-	volatile ConnectionRegistry connectionRegistry;
-
-	public static ContactChooserFragment newInstance(ContactId id) {
+	static ContactChooserFragment newInstance(ContactId id) {
 		Bundle args = new Bundle();
 
 		ContactChooserFragment fragment = new ContactChooserFragment();
@@ -73,6 +52,8 @@ public class ContactChooserFragment extends BaseFragment {
 	@Override
 	public void injectFragment(ActivityComponent component) {
 		component.inject(this);
+		viewModel = new ViewModelProvider(this, viewModelFactory)
+				.get(ContactListViewModel.class);
 	}
 
 	@Override
@@ -82,21 +63,20 @@ public class ContactChooserFragment extends BaseFragment {
 
 		View contentView = inflater.inflate(R.layout.list, container, false);
 
-		OnContactClickListener<ContactListItem> onContactClickListener =
-				(view, item) -> {
-					if (c1 == null) throw new IllegalStateException();
-					Contact c2 = item.getContact();
-					showMessageScreen(c1, c2);
-				};
-		adapter = new LegacyContactListAdapter(requireActivity(),
-				onContactClickListener);
-
 		list = contentView.findViewById(R.id.list);
 		list.setLayoutManager(new LinearLayoutManager(getActivity()));
 		list.setAdapter(adapter);
 		list.setEmptyText(R.string.no_contacts);
 
 		contactId = new ContactId(requireArguments().getInt(CONTACT_ID));
+		viewModel.setContactId(contactId);
+
+		viewModel.loadContacts();
+
+		viewModel.getContactListItems().observe(getViewLifecycleOwner(),
+				result -> result.onError(this::handleException)
+						.onSuccess(adapter::submitList)
+		);
 
 		return contentView;
 	}
@@ -104,14 +84,13 @@ public class ContactChooserFragment extends BaseFragment {
 	@Override
 	public void onStart() {
 		super.onStart();
-		loadContacts();
+		list.startPeriodicUpdate();
 	}
 
 	@Override
 	public void onStop() {
 		super.onStop();
-		adapter.clear();
-		list.showProgressBar();
+		list.stopPeriodicUpdate();
 	}
 
 	@Override
@@ -119,43 +98,15 @@ public class ContactChooserFragment extends BaseFragment {
 		return TAG;
 	}
 
-	private void loadContacts() {
-		listener.runOnDbThread(() -> {
-			try {
-				List<ContactListItem> contacts = new ArrayList<>();
-				for (Contact c : contactManager.getContacts()) {
-					if (c.getId().equals(contactId)) {
-						c1 = c;
-					} else {
-						AuthorInfo authorInfo = authorManager.getAuthorInfo(c);
-						ContactId id = c.getId();
-						GroupCount count =
-								conversationManager.getGroupCount(id);
-						boolean connected =
-								connectionRegistry.isConnected(c.getId());
-						contacts.add(new ContactListItem(c, authorInfo,
-								connected, count));
-					}
-				}
-				displayContacts(contacts);
-			} catch (DbException e) {
-				logException(LOG, WARNING, e);
-			}
-		});
-	}
-
-	private void displayContacts(List<ContactListItem> contacts) {
-		runOnUiThreadUnlessDestroyed(() -> {
-			if (contacts.isEmpty()) list.showData();
-			else adapter.addAll(contacts);
-		});
-	}
-
-	private void showMessageScreen(Contact c1, Contact c2) {
+	private void showMessageScreen(Contact other) {
 		IntroductionMessageFragment messageFragment =
-				IntroductionMessageFragment
-						.newInstance(c1.getId().getInt(), c2.getId().getInt());
+				IntroductionMessageFragment.newInstance(contactId.getInt(),
+						other.getId().getInt());
 		showNextFragment(messageFragment);
 	}
 
+	@Override
+	public void onItemClick(View view, ContactListItem item) {
+		showMessageScreen(item.getContact());
+	}
 }

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

@@ -0,0 +1,54 @@
+package org.briarproject.briar.android.introduction;
+
+import android.app.Application;
+
+import org.briarproject.bramble.api.connection.ConnectionRegistry;
+import org.briarproject.bramble.api.contact.ContactId;
+import org.briarproject.bramble.api.contact.ContactManager;
+import org.briarproject.bramble.api.db.DatabaseExecutor;
+import org.briarproject.bramble.api.db.TransactionManager;
+import org.briarproject.bramble.api.event.EventBus;
+import org.briarproject.bramble.api.lifecycle.LifecycleManager;
+import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
+import org.briarproject.bramble.api.system.AndroidExecutor;
+import org.briarproject.briar.android.contact.ContactsViewModel;
+import org.briarproject.briar.api.conversation.ConversationManager;
+import org.briarproject.briar.api.identity.AuthorManager;
+
+import java.util.concurrent.Executor;
+
+import javax.inject.Inject;
+
+import androidx.annotation.Nullable;
+
+import static java.util.Objects.requireNonNull;
+
+@NotNullByDefault
+class ContactListViewModel extends ContactsViewModel {
+
+	@Nullable
+	private ContactId contactId;
+
+	@Inject
+	ContactListViewModel(Application application,
+			@DatabaseExecutor Executor dbExecutor,
+			LifecycleManager lifecycleManager, TransactionManager db,
+			AndroidExecutor androidExecutor, ContactManager contactManager,
+			AuthorManager authorManager,
+			ConversationManager conversationManager,
+			ConnectionRegistry connectionRegistry, EventBus eventBus) {
+		super(application, dbExecutor, lifecycleManager, db, androidExecutor,
+				contactManager, authorManager, conversationManager,
+				connectionRegistry, eventBus);
+	}
+
+	void setContactId(ContactId contactId) {
+		this.contactId = contactId;
+	}
+
+	@Override
+	protected boolean displayContact(ContactId contactId) {
+		return !requireNonNull(this.contactId).equals(contactId);
+	}
+
+}

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

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

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

@@ -1,17 +1,13 @@
 package org.briarproject.briar.android.login;
 
 import android.content.Context;
-import android.graphics.drawable.Drawable;
 
 import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
 import org.briarproject.briar.R;
 
 import androidx.appcompat.app.AlertDialog;
 
-import static androidx.core.content.ContextCompat.getColor;
-import static androidx.core.content.ContextCompat.getDrawable;
-import static androidx.core.graphics.drawable.DrawableCompat.setTint;
-import static java.util.Objects.requireNonNull;
+import static org.briarproject.briar.android.util.UiUtils.getDialogIcon;
 
 @NotNullByDefault
 class LoginUtils {
@@ -19,9 +15,7 @@ class LoginUtils {
 	static AlertDialog createKeyStrengthenerErrorDialog(Context ctx) {
 		AlertDialog.Builder builder =
 				new AlertDialog.Builder(ctx, R.style.BriarDialogTheme);
-		Drawable icon = getDrawable(ctx, R.drawable.alerts_and_states_error);
-		setTint(requireNonNull(icon), getColor(ctx, R.color.color_primary));
-		builder.setIcon(icon);
+		builder.setIcon(getDialogIcon(ctx, R.drawable.alerts_and_states_error));
 		builder.setTitle(R.string.dialog_title_cannot_check_password);
 		builder.setMessage(R.string.dialog_message_cannot_check_password);
 		builder.setPositiveButton(R.string.ok, null);

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

@@ -2,6 +2,7 @@ package org.briarproject.briar.android.navdrawer;
 
 import android.content.Intent;
 import android.content.res.Configuration;
+import android.graphics.drawable.Drawable;
 import android.net.Uri;
 import android.os.Bundle;
 import android.view.LayoutInflater;
@@ -59,6 +60,7 @@ import androidx.fragment.app.FragmentTransaction;
 import androidx.lifecycle.MutableLiveData;
 import androidx.lifecycle.ViewModelProvider;
 import androidx.lifecycle.ViewModelProviders;
+import androidx.vectordrawable.graphics.drawable.VectorDrawableCompat;
 import uk.co.samuelwall.materialtaptargetprompt.MaterialTapTargetPrompt;
 
 import static android.view.View.GONE;
@@ -433,8 +435,7 @@ public class NavDrawerActivity extends BriarActivity implements
 				Transport t = getItem(position);
 
 				ImageView icon = view.findViewById(R.id.imageView);
-				icon.setImageDrawable(ContextCompat.getDrawable(
-						NavDrawerActivity.this, t.iconDrawable));
+				icon.setImageResource(t.iconDrawable);
 				icon.setColorFilter(ContextCompat.getColor(
 						NavDrawerActivity.this, t.iconColor));
 
@@ -476,11 +477,13 @@ public class NavDrawerActivity extends BriarActivity implements
 	private void showTransportsOnboarding(boolean show, ImageView imageView) {
 		if (show) {
 			int color = resolveColorAttribute(this, R.attr.colorControlNormal);
+			Drawable drawable = VectorDrawableCompat
+					.create(getResources(), R.drawable.transport_tor, null);
 			new MaterialTapTargetPrompt.Builder(NavDrawerActivity.this,
 					R.style.OnboardingDialogTheme).setTarget(imageView)
 					.setPrimaryText(R.string.network_settings_title)
 					.setSecondaryText(R.string.transports_onboarding_text)
-					.setIcon(R.drawable.transport_tor)
+					.setIconDrawable(drawable)
 					.setIconDrawableColourFilter(color)
 					.setBackgroundColour(
 							ContextCompat.getColor(this, R.color.briar_primary))

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

@@ -141,8 +141,7 @@ public class TransportsActivity extends BriarActivity {
 				Transport t = getItem(position);
 
 				ImageView icon = view.findViewById(R.id.icon);
-				icon.setImageDrawable(ContextCompat.getDrawable(
-						TransportsActivity.this, t.iconDrawable));
+				icon.setImageResource(t.iconDrawable);
 				icon.setColorFilter(ContextCompat.getColor(
 						TransportsActivity.this, t.iconColor));
 

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

@@ -1,67 +1,60 @@
 package org.briarproject.briar.android.privategroup.conversation;
 
-import android.content.DialogInterface;
-import android.content.DialogInterface.OnClickListener;
 import android.content.Intent;
 import android.os.Bundle;
 import android.view.Menu;
 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.identity.LocalAuthor;
 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.UiExceptionHandler;
-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;
 import org.briarproject.briar.android.privategroup.reveal.RevealContactsActivity;
 import org.briarproject.briar.android.threaded.ThreadListActivity;
-import org.briarproject.briar.android.threaded.ThreadListController;
-import org.briarproject.briar.api.privategroup.PrivateGroup;
-import org.briarproject.briar.api.privategroup.Visibility;
+import org.briarproject.briar.android.threaded.ThreadListViewModel;
 
 import javax.annotation.Nullable;
 import javax.inject.Inject;
 
 import androidx.appcompat.app.AlertDialog;
 import androidx.appcompat.widget.Toolbar;
-import androidx.recyclerview.widget.LinearLayoutManager;
+import androidx.lifecycle.ViewModelProvider;
 
 import static android.view.View.GONE;
 import static android.view.View.VISIBLE;
+import static org.briarproject.bramble.api.nullsafety.NullSafety.requireNonNull;
 import static org.briarproject.briar.android.activity.RequestCodes.REQUEST_GROUP_INVITE;
+import static org.briarproject.briar.android.util.UiUtils.observeOnce;
 import static org.briarproject.briar.api.privategroup.PrivateGroupConstants.MAX_GROUP_POST_TEXT_LENGTH;
 
 @MethodsNotNullByDefault
 @ParametersNotNullByDefault
 public class GroupActivity extends
-		ThreadListActivity<PrivateGroup, GroupMessageItem, GroupMessageAdapter>
-		implements GroupListener, OnClickListener {
+		ThreadListActivity<GroupMessageItem, GroupMessageAdapter> {
 
 	@Inject
-	GroupController controller;
+	ViewModelProvider.Factory viewModelFactory;
 
-	@Nullable
-	private Boolean isCreator = null;
-	private boolean isDissolved = false;
-	private MenuItem revealMenuItem, inviteMenuItem, leaveMenuItem,
-			dissolveMenuItem;
+	private GroupViewModel viewModel;
 
 	@Override
 	public void injectActivity(ActivityComponent component) {
 		component.inject(this);
+		viewModel = new ViewModelProvider(this, viewModelFactory)
+				.get(GroupViewModel.class);
 	}
 
 	@Override
-	protected ThreadListController<PrivateGroup, GroupMessageItem> getController() {
-		return controller;
+	protected ThreadListViewModel<GroupMessageItem> getViewModel() {
+		return viewModel;
+	}
+
+	@Override
+	protected GroupMessageAdapter createAdapter() {
+		return new GroupMessageAdapter(this);
 	}
 
 	@Override
@@ -69,65 +62,27 @@ public class GroupActivity extends
 		super.onCreate(state);
 
 		Toolbar toolbar = setUpCustomToolbar(false);
-
-		Intent i = getIntent();
-		String groupName = i.getStringExtra(GROUP_NAME);
-		if (groupName != null) setTitle(groupName);
-		loadNamedGroup();
-
 		// Open member list on Toolbar click
-		if (toolbar != null) {
-			toolbar.setOnClickListener(v -> {
-				Intent i1 = new Intent(GroupActivity.this,
-						GroupMemberListActivity.class);
-				i1.putExtra(GROUP_ID, groupId.getBytes());
-				startActivity(i1);
-			});
-		}
+		toolbar.setOnClickListener(v -> {
+			Intent i = new Intent(GroupActivity.this,
+					GroupMemberListActivity.class);
+			i.putExtra(GROUP_ID, groupId.getBytes());
+			startActivity(i);
+		});
 
+		String groupName = getIntent().getStringExtra(GROUP_NAME);
+		if (groupName != null) setTitle(groupName);
+		observeOnce(viewModel.getPrivateGroup(), this, privateGroup ->
+				setTitle(privateGroup.getName())
+		);
+		observeOnce(viewModel.isCreator(), this, adapter::setIsCreator);
+
+		// start with group disabled and enable when not dissolved
 		setGroupEnabled(false);
-	}
-
-	@Override
-	protected GroupMessageAdapter createAdapter(
-			LinearLayoutManager layoutManager) {
-		return new GroupMessageAdapter(this, layoutManager);
-	}
-
-	@Override
-	protected void loadItems() {
-		controller.isDissolved(
-				new UiResultExceptionHandler<Boolean, DbException>(this) {
-					@Override
-					public void onResultUi(Boolean isDissolved) {
-						setGroupEnabled(!isDissolved);
-						GroupActivity.super.loadItems();
-					}
-
-					@Override
-					public void onExceptionUi(DbException exception) {
-						handleException(exception);
-					}
-				});
-	}
-
-	@Override
-	protected void onNamedGroupLoaded(PrivateGroup group) {
-		setTitle(group.getName());
-		controller.loadLocalAuthor(
-				new UiResultExceptionHandler<LocalAuthor, DbException>(this) {
-					@Override
-					public void onResultUi(LocalAuthor author) {
-						isCreator = group.getCreator().equals(author);
-						adapter.setPerspective(isCreator);
-						showMenuItems();
-					}
-
-					@Override
-					public void onExceptionUi(DbException exception) {
-						handleException(exception);
-					}
-				});
+		viewModel.isDissolved().observeEvent(this, dissolved -> {
+			setGroupEnabled(!dissolved);
+			if (dissolved) onGroupDissolved();
+		});
 	}
 
 	@Override
@@ -136,74 +91,61 @@ public class GroupActivity extends
 		MenuInflater inflater = getMenuInflater();
 		inflater.inflate(R.menu.group_actions, menu);
 
-		revealMenuItem = menu.findItem(R.id.action_group_reveal);
-		inviteMenuItem = menu.findItem(R.id.action_group_invite);
-		leaveMenuItem = menu.findItem(R.id.action_group_leave);
-		dissolveMenuItem = menu.findItem(R.id.action_group_dissolve);
-
-		// all role-dependent items are invisible until we know our role
-		revealMenuItem.setVisible(false);
-		inviteMenuItem.setVisible(false);
-		leaveMenuItem.setVisible(false);
-		dissolveMenuItem.setVisible(false);
-
-		// show items based on role
-		showMenuItems();
-
-		return super.onCreateOptionsMenu(menu);
+		// show items based on role (which will not change, so observe once)
+		observeOnce(viewModel.isCreator(), this, isCreator -> {
+			menu.findItem(R.id.action_group_reveal).setVisible(!isCreator);
+			menu.findItem(R.id.action_group_invite).setVisible(isCreator);
+			menu.findItem(R.id.action_group_leave).setVisible(!isCreator);
+			menu.findItem(R.id.action_group_dissolve).setVisible(isCreator);
+		});
+		super.onCreateOptionsMenu(menu);
+		return true;
 	}
 
 	@Override
 	public boolean onOptionsItemSelected(MenuItem item) {
-		switch (item.getItemId()) {
-			case R.id.action_group_member_list:
-				Intent i1 = new Intent(this, GroupMemberListActivity.class);
-				i1.putExtra(GROUP_ID, groupId.getBytes());
-				startActivity(i1);
-				return true;
-			case R.id.action_group_reveal:
-				if (isCreator == null || isCreator)
-					throw new IllegalStateException();
-				Intent i2 = new Intent(this, RevealContactsActivity.class);
-				i2.putExtra(GROUP_ID, groupId.getBytes());
-				startActivity(i2);
-				return true;
-			case R.id.action_group_invite:
-				if (isCreator == null || !isCreator)
-					throw new IllegalStateException();
-				Intent i3 = new Intent(this, GroupInviteActivity.class);
-				i3.putExtra(GROUP_ID, groupId.getBytes());
-				startActivityForResult(i3, REQUEST_GROUP_INVITE);
-				return true;
-			case R.id.action_group_leave:
-				if (isCreator == null || isCreator)
-					throw new IllegalStateException();
-				showLeaveGroupDialog();
-				return true;
-			case R.id.action_group_dissolve:
-				if (isCreator == null || !isCreator)
-					throw new IllegalStateException();
-				showDissolveGroupDialog();
-			default:
-				return super.onOptionsItemSelected(item);
+		int itemId = item.getItemId();
+		if (itemId == R.id.action_group_member_list) {
+			Intent i = new Intent(this, GroupMemberListActivity.class);
+			i.putExtra(GROUP_ID, groupId.getBytes());
+			startActivity(i);
+			return true;
+		} else if (itemId == R.id.action_group_reveal) {
+			if (requireNonNull(viewModel.isCreator().getValue()))
+				throw new IllegalStateException();
+			Intent i = new Intent(this, RevealContactsActivity.class);
+			i.putExtra(GROUP_ID, groupId.getBytes());
+			startActivity(i);
+			return true;
+		} else if (itemId == R.id.action_group_invite) {
+			if (!requireNonNull(viewModel.isCreator().getValue()))
+				throw new IllegalStateException();
+			Intent i = new Intent(this, GroupInviteActivity.class);
+			i.putExtra(GROUP_ID, groupId.getBytes());
+			startActivityForResult(i, REQUEST_GROUP_INVITE);
+			return true;
+		} else if (itemId == R.id.action_group_leave) {
+			if (requireNonNull(viewModel.isCreator().getValue()))
+				throw new IllegalStateException();
+			showLeaveGroupDialog();
+			return true;
+		} else if (itemId == R.id.action_group_dissolve) {
+			if (!requireNonNull(viewModel.isCreator().getValue()))
+				throw new IllegalStateException();
+			showDissolveGroupDialog();
+			return true;
 		}
+		return super.onOptionsItemSelected(item);
 	}
 
 	@Override
-	protected void onActivityResult(int request, int result, Intent data) {
+	protected void onActivityResult(int request, int result,
+			@Nullable Intent data) {
 		if (request == REQUEST_GROUP_INVITE && result == RESULT_OK) {
 			displaySnackbar(R.string.groups_invitation_sent);
 		} 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;
@@ -211,11 +153,11 @@ public class GroupActivity extends
 
 	@Override
 	public void onReplyClick(GroupMessageItem item) {
-		if (!isDissolved) super.onReplyClick(item);
+		Boolean isDissolved = viewModel.isDissolved().getLastValue();
+		if (isDissolved != null && !isDissolved) super.onReplyClick(item);
 	}
 
 	private void setGroupEnabled(boolean enabled) {
-		isDissolved = !enabled;
 		sendController.setReady(enabled);
 		list.getRecyclerView().setAlpha(enabled ? 1f : 0.5f);
 
@@ -227,21 +169,13 @@ 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);
 		builder.setTitle(getString(R.string.groups_leave_dialog_title));
 		builder.setMessage(getString(R.string.groups_leave_dialog_message));
-		builder.setNegativeButton(R.string.dialog_button_leave, this);
+		builder.setNegativeButton(R.string.dialog_button_leave,
+				(d, w) -> deleteGroup());
 		builder.setPositiveButton(R.string.cancel, null);
 		builder.show();
 	}
@@ -251,37 +185,19 @@ public class GroupActivity extends
 				new AlertDialog.Builder(this, R.style.BriarDialogTheme);
 		builder.setTitle(getString(R.string.groups_dissolve_dialog_title));
 		builder.setMessage(getString(R.string.groups_dissolve_dialog_message));
-		builder.setNegativeButton(R.string.groups_dissolve_button, this);
+		builder.setNegativeButton(R.string.groups_dissolve_button,
+				(d, w) -> deleteGroup());
 		builder.setPositiveButton(R.string.cancel, null);
 		builder.show();
 	}
 
-	@Override
-	public void onClick(DialogInterface dialog, int which) {
-		controller.deleteNamedGroup(
-				new UiExceptionHandler<DbException>(this) {
-					// The activity is going to be destroyed by the
-					// GroupRemovedEvent being fired
-					@Override
-					public void onExceptionUi(DbException exception) {
-						handleException(exception);
-					}
-				});
+	private void deleteGroup() {
+		// The activity is going to be destroyed by the
+		// GroupRemovedEvent being fired
+		viewModel.deletePrivateGroup();
 	}
 
-	@Override
-	public void onContactRelationshipRevealed(AuthorId memberId, ContactId c,
-			Visibility v) {
-		adapter.updateVisibility(memberId, v);
-
-		sharingController.add(c);
-		setToolbarSubTitle(sharingController.getTotalCount(),
-				sharingController.getOnlineCount());
-	}
-
-	@Override
-	public void onGroupDissolved() {
-		setGroupEnabled(false);
+	private void onGroupDissolved() {
 		AlertDialog.Builder builder =
 				new AlertDialog.Builder(this, R.style.BriarDialogTheme);
 		builder.setTitle(getString(R.string.groups_dissolved_dialog_title));

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

@@ -1,33 +0,0 @@
-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.bramble.api.identity.LocalAuthor;
-import org.briarproject.briar.android.controller.handler.ResultExceptionHandler;
-import org.briarproject.briar.android.threaded.ThreadListController;
-import org.briarproject.briar.api.privategroup.PrivateGroup;
-import org.briarproject.briar.api.privategroup.Visibility;
-
-import androidx.annotation.UiThread;
-
-public interface GroupController
-		extends ThreadListController<PrivateGroup, GroupMessageItem> {
-
-	void loadLocalAuthor(
-			ResultExceptionHandler<LocalAuthor, DbException> handler);
-
-	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

@@ -1,242 +0,0 @@
-package org.briarproject.briar.android.privategroup.conversation;
-
-import org.briarproject.bramble.api.contact.ContactId;
-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.event.Event;
-import org.briarproject.bramble.api.event.EventBus;
-import org.briarproject.bramble.api.identity.IdentityManager;
-import org.briarproject.bramble.api.identity.LocalAuthor;
-import org.briarproject.bramble.api.lifecycle.LifecycleManager;
-import org.briarproject.bramble.api.nullsafety.MethodsNotNullByDefault;
-import org.briarproject.bramble.api.nullsafety.ParametersNotNullByDefault;
-import org.briarproject.bramble.api.sync.MessageId;
-import org.briarproject.bramble.api.system.Clock;
-import org.briarproject.briar.android.controller.handler.ResultExceptionHandler;
-import org.briarproject.briar.android.privategroup.conversation.GroupController.GroupListener;
-import org.briarproject.briar.android.threaded.ThreadListControllerImpl;
-import org.briarproject.briar.api.android.AndroidNotificationManager;
-import org.briarproject.briar.api.client.MessageTracker;
-import org.briarproject.briar.api.client.MessageTracker.GroupCount;
-import org.briarproject.briar.api.privategroup.GroupMember;
-import org.briarproject.briar.api.privategroup.GroupMessage;
-import org.briarproject.briar.api.privategroup.GroupMessageFactory;
-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.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;
-import java.util.Collection;
-import java.util.concurrent.Executor;
-import java.util.logging.Logger;
-
-import javax.annotation.Nullable;
-import javax.inject.Inject;
-
-import static java.lang.Math.max;
-import static java.util.logging.Level.WARNING;
-import static org.briarproject.bramble.util.LogUtils.logException;
-
-@MethodsNotNullByDefault
-@ParametersNotNullByDefault
-class GroupControllerImpl extends
-		ThreadListControllerImpl<PrivateGroup, GroupMessageItem, GroupMessageHeader, GroupMessage, GroupListener>
-		implements GroupController {
-
-	private static final Logger LOG =
-			Logger.getLogger(GroupControllerImpl.class.getName());
-
-	private final PrivateGroupManager privateGroupManager;
-	private final GroupMessageFactory groupMessageFactory;
-
-	@Inject
-	GroupControllerImpl(@DatabaseExecutor Executor dbExecutor,
-			LifecycleManager lifecycleManager, IdentityManager identityManager,
-			@CryptoExecutor Executor cryptoExecutor,
-			PrivateGroupManager privateGroupManager,
-			GroupMessageFactory groupMessageFactory, EventBus eventBus,
-			MessageTracker messageTracker, Clock clock,
-			AndroidNotificationManager notificationManager) {
-		super(dbExecutor, lifecycleManager, identityManager, cryptoExecutor,
-				eventBus, clock, notificationManager, messageTracker);
-		this.privateGroupManager = privateGroupManager;
-		this.groupMessageFactory = groupMessageFactory;
-	}
-
-	@Override
-	public void onActivityStart() {
-		super.onActivityStart();
-		notificationManager.clearGroupMessageNotification(getGroupId());
-	}
-
-	@Override
-	public void eventOccurred(Event e) {
-		super.eventOccurred(e);
-
-		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) {
-			ContactRelationshipRevealedEvent c =
-					(ContactRelationshipRevealedEvent) e;
-			if (getGroupId().equals(c.getGroupId())) {
-				listener.onContactRelationshipRevealed(c.getMemberId(),
-						c.getContactId(), c.getVisibility());
-			}
-		} else if (e instanceof GroupInvitationResponseReceivedEvent) {
-			GroupInvitationResponseReceivedEvent g =
-					(GroupInvitationResponseReceivedEvent) e;
-			GroupInvitationResponse r = g.getMessageHeader();
-			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();
-			}
-		}
-	}
-
-	@Override
-	protected PrivateGroup loadNamedGroup() throws DbException {
-		return privateGroupManager.getPrivateGroup(getGroupId());
-	}
-
-	@Override
-	protected Collection<GroupMessageHeader> loadHeaders() throws DbException {
-		return privateGroupManager.getHeaders(getGroupId());
-	}
-
-	@Override
-	protected String loadMessageText(GroupMessageHeader header)
-			throws DbException {
-		if (header instanceof JoinMessageHeader) {
-			// will be looked up later
-			return "";
-		}
-		return privateGroupManager.getMessageText(header.getId());
-	}
-
-	@Override
-	protected void markRead(MessageId id) throws DbException {
-		privateGroupManager.setReadFlag(getGroupId(), id, true);
-	}
-
-	@Override
-	public void loadSharingContacts(
-			ResultExceptionHandler<Collection<ContactId>, DbException> handler) {
-		runOnDbThread(() -> {
-			try {
-				Collection<GroupMember> members =
-						privateGroupManager.getMembers(getGroupId());
-				Collection<ContactId> contactIds = new ArrayList<>();
-				for (GroupMember m : members) {
-					if (m.getContactId() != null)
-						contactIds.add(m.getContactId());
-				}
-				handler.onResult(contactIds);
-			} catch (DbException e) {
-				logException(LOG, WARNING, e);
-				handler.onException(e);
-			}
-		});
-	}
-
-	@Override
-	public void createAndStoreMessage(String text,
-			@Nullable GroupMessageItem parentItem,
-			ResultExceptionHandler<GroupMessageItem, DbException> handler) {
-		runOnDbThread(() -> {
-			try {
-				LocalAuthor author = identityManager.getLocalAuthor();
-				MessageId parentId = null;
-				MessageId previousMsgId =
-						privateGroupManager.getPreviousMsgId(getGroupId());
-				GroupCount count =
-						privateGroupManager.getGroupCount(getGroupId());
-				long timestamp = count.getLatestMsgTime();
-				if (parentItem != null) parentId = parentItem.getId();
-				timestamp = max(clock.currentTimeMillis(), timestamp + 1);
-				createMessage(text, timestamp, parentId, author, previousMsgId,
-						handler);
-			} catch (DbException e) {
-				logException(LOG, WARNING, e);
-				handler.onException(e);
-			}
-		});
-	}
-
-	private void createMessage(String text, long timestamp,
-			@Nullable MessageId parentId, LocalAuthor author,
-			MessageId previousMsgId,
-			ResultExceptionHandler<GroupMessageItem, DbException> handler) {
-		cryptoExecutor.execute(() -> {
-			LOG.info("Creating group message...");
-			GroupMessage msg = groupMessageFactory
-					.createGroupMessage(getGroupId(), timestamp,
-							parentId, author, text, previousMsgId);
-			storePost(msg, text, handler);
-		});
-	}
-
-	@Override
-	protected GroupMessageHeader addLocalMessage(GroupMessage message)
-			throws DbException {
-		return privateGroupManager.addLocalMessage(message);
-	}
-
-	@Override
-	protected void deleteNamedGroup(PrivateGroup group) throws DbException {
-		privateGroupManager.removePrivateGroup(group.getId());
-	}
-
-	@Override
-	protected GroupMessageItem buildItem(GroupMessageHeader header,
-			String text) {
-		if (header instanceof JoinMessageHeader) {
-			return new JoinMessageItem((JoinMessageHeader) header, text);
-		}
-		return new GroupMessageItem(header, text);
-	}
-
-	@Override
-	public void loadLocalAuthor(
-			ResultExceptionHandler<LocalAuthor, DbException> handler) {
-		runOnDbThread(() -> {
-			try {
-				LocalAuthor author = identityManager.getLocalAuthor();
-				handler.onResult(author);
-			} catch (DbException e) {
-				logException(LOG, WARNING, e);
-				handler.onException(e);
-			}
-		});
-	}
-
-	@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/GroupConversationModule.java

@@ -1,19 +1,18 @@
 package org.briarproject.briar.android.privategroup.conversation;
 
-import org.briarproject.briar.android.activity.ActivityScope;
-import org.briarproject.briar.android.activity.BaseActivity;
+import org.briarproject.briar.android.viewmodel.ViewModelKey;
 
+import androidx.lifecycle.ViewModel;
+import dagger.Binds;
 import dagger.Module;
-import dagger.Provides;
+import dagger.multibindings.IntoMap;
 
 @Module
-public class GroupConversationModule {
+public interface GroupConversationModule {
+
+	@Binds
+	@IntoMap
+	@ViewModelKey(GroupViewModel.class)
+	ViewModel bindGroupViewModel(GroupViewModel groupViewModel);
 
-	@ActivityScope
-	@Provides
-	GroupController provideGroupController(BaseActivity activity,
-			GroupControllerImpl groupController) {
-		activity.addLifecycleController(groupController);
-		return groupController;
-	}
 }

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

@@ -4,19 +4,14 @@ import android.view.LayoutInflater;
 import android.view.View;
 import android.view.ViewGroup;
 
-import org.briarproject.bramble.api.identity.AuthorId;
 import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
 import org.briarproject.briar.R;
 import org.briarproject.briar.android.threaded.BaseThreadItemViewHolder;
 import org.briarproject.briar.android.threaded.ThreadItemAdapter;
 import org.briarproject.briar.android.threaded.ThreadPostViewHolder;
-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;
 
 @UiThread
 @NotNullByDefault
@@ -24,15 +19,14 @@ 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
 	@Override
 	public int getItemViewType(int position) {
-		GroupMessageItem item = items.get(position);
+		GroupMessageItem item = getItem(position);
 		return item.getLayout();
 	}
 
@@ -47,30 +41,9 @@ class GroupMessageAdapter extends ThreadItemAdapter<GroupMessageItem> {
 		return new ThreadPostViewHolder<>(v);
 	}
 
-	void setPerspective(boolean isCreator) {
+	void setIsCreator(boolean isCreator) {
 		this.isCreator = isCreator;
 		notifyDataSetChanged();
 	}
 
-	void updateVisibility(AuthorId memberId, Visibility v) {
-		int position = findItemPosition(memberId);
-		if (position != NO_POSITION) {
-			GroupMessageItem item = items.get(position);
-			if (item instanceof JoinMessageItem) {
-				((JoinMessageItem) item).setVisibility(v);
-				notifyItemChanged(findItemPosition(item), item);
-			}
-		}
-	}
-
-	private int findItemPosition(AuthorId a) {
-		int count = items.size();
-		for (int i = 0; i < count; i++) {
-			GroupMessageItem item = items.get(i);
-			if (item.getAuthor().getId().equals(a))
-				return i;
-		}
-		return NO_POSITION; // Not found
-	}
-
 }

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

@@ -0,0 +1,289 @@
+package org.briarproject.briar.android.privategroup.conversation;
+
+import android.app.Application;
+
+import org.briarproject.bramble.api.contact.ContactId;
+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.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.identity.Author;
+import org.briarproject.bramble.api.identity.IdentityManager;
+import org.briarproject.bramble.api.identity.LocalAuthor;
+import org.briarproject.bramble.api.lifecycle.LifecycleManager;
+import org.briarproject.bramble.api.nullsafety.MethodsNotNullByDefault;
+import org.briarproject.bramble.api.nullsafety.ParametersNotNullByDefault;
+import org.briarproject.bramble.api.sync.GroupId;
+import org.briarproject.bramble.api.sync.MessageId;
+import org.briarproject.bramble.api.system.AndroidExecutor;
+import org.briarproject.bramble.api.system.Clock;
+import org.briarproject.briar.android.sharing.SharingController;
+import org.briarproject.briar.android.threaded.ThreadListViewModel;
+import org.briarproject.briar.android.viewmodel.LiveEvent;
+import org.briarproject.briar.android.viewmodel.MutableLiveEvent;
+import org.briarproject.briar.api.android.AndroidNotificationManager;
+import org.briarproject.briar.api.client.MessageTracker;
+import org.briarproject.briar.api.client.MessageTracker.GroupCount;
+import org.briarproject.briar.api.privategroup.GroupMember;
+import org.briarproject.briar.api.privategroup.GroupMessage;
+import org.briarproject.briar.api.privategroup.GroupMessageFactory;
+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.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;
+import java.util.Collection;
+import java.util.List;
+import java.util.concurrent.Executor;
+import java.util.logging.Logger;
+
+import javax.annotation.Nullable;
+import javax.inject.Inject;
+
+import androidx.lifecycle.LiveData;
+import androidx.lifecycle.MutableLiveData;
+
+import static java.lang.Math.max;
+import static java.util.logging.Level.WARNING;
+import static java.util.logging.Logger.getLogger;
+import static org.briarproject.bramble.util.LogUtils.logDuration;
+import static org.briarproject.bramble.util.LogUtils.logException;
+import static org.briarproject.bramble.util.LogUtils.now;
+
+@MethodsNotNullByDefault
+@ParametersNotNullByDefault
+class GroupViewModel extends ThreadListViewModel<GroupMessageItem> {
+
+	private static final Logger LOG = getLogger(GroupViewModel.class.getName());
+
+	private final PrivateGroupManager privateGroupManager;
+	private final GroupMessageFactory groupMessageFactory;
+
+	private final MutableLiveData<PrivateGroup> privateGroup =
+			new MutableLiveData<>();
+	private final MutableLiveData<Boolean> isCreator = new MutableLiveData<>();
+	private final MutableLiveEvent<Boolean> isDissolved =
+			new MutableLiveEvent<>();
+
+	@Inject
+	GroupViewModel(Application application,
+			@DatabaseExecutor Executor dbExecutor,
+			LifecycleManager lifecycleManager,
+			TransactionManager db,
+			AndroidExecutor androidExecutor,
+			EventBus eventBus,
+			IdentityManager identityManager,
+			AndroidNotificationManager notificationManager,
+			SharingController sharingController,
+			@CryptoExecutor Executor cryptoExecutor,
+			Clock clock,
+			MessageTracker messageTracker,
+			PrivateGroupManager privateGroupManager,
+			GroupMessageFactory groupMessageFactory) {
+		super(application, dbExecutor, lifecycleManager, db, androidExecutor,
+				identityManager, notificationManager, sharingController,
+				cryptoExecutor, clock, messageTracker, eventBus);
+		this.privateGroupManager = privateGroupManager;
+		this.groupMessageFactory = groupMessageFactory;
+	}
+
+	@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, false);
+				// In case the join message comes from the creator,
+				// we need to reload the sharing contacts
+				// in case it was delayed and the sharing count is wrong (#850).
+				if (item instanceof JoinMessageItem &&
+						(((JoinMessageItem) item).isInitial())) {
+					loadSharingContacts();
+				}
+			}
+		} else if (e instanceof GroupInvitationResponseReceivedEvent) {
+			GroupInvitationResponseReceivedEvent g =
+					(GroupInvitationResponseReceivedEvent) e;
+			GroupInvitationResponse r = g.getMessageHeader();
+			if (r.getShareableId().equals(groupId) && r.wasAccepted()) {
+				sharingController.add(g.getContactId());
+			}
+		} else if (e instanceof ContactRelationshipRevealedEvent) {
+			ContactRelationshipRevealedEvent c =
+					(ContactRelationshipRevealedEvent) e;
+			if (c.getGroupId().equals(groupId)) {
+				sharingController.add(c.getContactId());
+			}
+		} else if (e instanceof GroupDissolvedEvent) {
+			GroupDissolvedEvent g = (GroupDissolvedEvent) e;
+			if (g.getGroupId().equals(groupId)) {
+				isDissolved.setEvent(true);
+			}
+		} else {
+			super.eventOccurred(e);
+		}
+	}
+
+	@Override
+	protected void performInitialLoad() {
+		super.performInitialLoad();
+		loadPrivateGroup(groupId);
+	}
+
+	protected void clearNotifications() {
+		notificationManager.clearGroupMessageNotification(groupId);
+	}
+
+	private void loadPrivateGroup(GroupId groupId) {
+		runOnDbThread(() -> {
+			try {
+				PrivateGroup g = privateGroupManager.getPrivateGroup(groupId);
+				privateGroup.postValue(g);
+				Author author = identityManager.getLocalAuthor();
+				isCreator.postValue(g.getCreator().equals(author));
+			} catch (DbException e) {
+				logException(LOG, WARNING, e);
+			}
+		});
+	}
+
+	@Override
+	public void loadItems() {
+		loadList(txn -> {
+			// check first if group is dissolved
+			isDissolved
+					.postEvent(privateGroupManager.isDissolved(txn, groupId));
+			// now continue to load the items
+			long start = now();
+			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));
+			}
+			logDuration(LOG, "Loading bodies and creating items", start);
+			return items;
+		}, this::setItems);
+	}
+
+	private GroupMessageItem loadItem(Transaction txn,
+			GroupMessageHeader header) throws DbException {
+		String text;
+		if (header instanceof JoinMessageHeader) {
+			// will be looked up later
+			text = "";
+		} else {
+			text = privateGroupManager.getMessageText(txn, header.getId());
+		}
+		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);
+	}
+
+	@Override
+	public void createAndStoreMessage(String text,
+			@Nullable MessageId parentId) {
+		runOnDbThread(() -> {
+			try {
+				LocalAuthor author = identityManager.getLocalAuthor();
+				MessageId previousMsgId =
+						privateGroupManager.getPreviousMsgId(groupId);
+				GroupCount count = privateGroupManager.getGroupCount(groupId);
+				long timestamp = count.getLatestMsgTime();
+				timestamp = max(clock.currentTimeMillis(), timestamp + 1);
+				createMessage(text, timestamp, parentId, author, previousMsgId);
+			} catch (DbException e) {
+				logException(LOG, WARNING, e);
+			}
+		});
+	}
+
+	private void createMessage(String text, long timestamp,
+			@Nullable MessageId parentId, LocalAuthor author,
+			MessageId previousMsgId) {
+		cryptoExecutor.execute(() -> {
+			LOG.info("Creating group message...");
+			GroupMessage msg = groupMessageFactory.createGroupMessage(groupId,
+					timestamp, parentId, author, text, previousMsgId);
+			storePost(msg, text);
+		});
+	}
+
+	private void storePost(GroupMessage msg, String text) {
+		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)
+			);
+		}, e -> logException(LOG, WARNING, e));
+	}
+
+	@Override
+	protected void markItemRead(GroupMessageItem item) {
+		runOnDbThread(() -> {
+			try {
+				privateGroupManager.setReadFlag(groupId, item.getId(), true);
+			} catch (DbException e) {
+				logException(LOG, WARNING, e);
+			}
+		});
+	}
+
+	public void loadSharingContacts() {
+		runOnDbThread(true, txn -> {
+			Collection<GroupMember> members =
+					privateGroupManager.getMembers(txn, groupId);
+			Collection<ContactId> contactIds = new ArrayList<>();
+			for (GroupMember m : members) {
+				if (m.getContactId() != null)
+					contactIds.add(m.getContactId());
+			}
+			txn.attach(() -> sharingController.addAll(contactIds));
+		}, e -> logException(LOG, WARNING, e));
+	}
+
+	void deletePrivateGroup() {
+		runOnDbThread(() -> {
+			try {
+				privateGroupManager.removePrivateGroup(groupId);
+			} catch (DbException e) {
+				logException(LOG, WARNING, e);
+			}
+		});
+	}
+
+	LiveData<PrivateGroup> getPrivateGroup() {
+		return privateGroup;
+	}
+
+	LiveData<Boolean> isCreator() {
+		return isCreator;
+	}
+
+	LiveEvent<Boolean> isDissolved() {
+		return isDissolved;
+	}
+
+}

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

@@ -2,7 +2,6 @@ package org.briarproject.briar.android.privategroup.conversation;
 
 import org.briarproject.briar.R;
 import org.briarproject.briar.api.privategroup.JoinMessageHeader;
-import org.briarproject.briar.api.privategroup.Visibility;
 
 import javax.annotation.concurrent.NotThreadSafe;
 
@@ -13,13 +12,11 @@ import androidx.annotation.UiThread;
 @NotThreadSafe
 class JoinMessageItem extends GroupMessageItem {
 
-	private Visibility visibility;
 	private final boolean isInitial;
 
 	JoinMessageItem(JoinMessageHeader h, String text) {
 		super(h, text);
-		this.visibility = h.getVisibility();
-		this.isInitial = h.isInitial();
+		isInitial = h.isInitial();
 	}
 
 	@Override
@@ -33,14 +30,6 @@ class JoinMessageItem extends GroupMessageItem {
 		return R.layout.list_item_group_join_notice;
 	}
 
-	Visibility getVisibility() {
-		return visibility;
-	}
-
-	void setVisibility(Visibility visibility) {
-		this.visibility = visibility;
-	}
-
 	boolean isInitial() {
 		return isInitial;
 	}

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

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

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

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

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

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

briar-android/src/main/java/org/briarproject/briar/android/sharing/SharingController.java

@@ -0,0 +1,54 @@
+package org.briarproject.briar.android.sharing;
+
+import org.briarproject.bramble.api.contact.ContactId;
+import org.briarproject.bramble.api.event.EventBus;
+import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
+
+import java.util.Collection;
+
+import androidx.annotation.UiThread;
+import androidx.lifecycle.LiveData;
+
+@NotNullByDefault
+public interface SharingController {
+
+	/**
+	 * Call this when the owning ViewModel gets cleared,
+	 * so the {@link EventBus} can get unregistered.
+	 */
+	void onCleared();
+
+	/**
+	 * Adds one contact to be tracked.
+	 */
+	@UiThread
+	void add(ContactId c);
+
+	/**
+	 * Adds a collection of contacts to be tracked.
+	 */
+	@UiThread
+	void addAll(Collection<ContactId> contacts);
+
+	/**
+	 * Call this when the contact identified by c is no longer sharing
+	 * the given group identified by GroupId g.
+	 */
+	@UiThread
+	void remove(ContactId c);
+
+	/**
+	 * Returns the total number of contacts that have been added.
+	 */
+	LiveData<SharingInfo> getSharingInfo();
+
+	class SharingInfo {
+		public final int total, online;
+
+		SharingInfo(int total, int online) {
+			this.total = total;
+			this.online = online;
+		}
+	}
+
+}

briar-android/src/main/java/org/briarproject/briar/android/sharing/SharingControllerImpl.java

@@ -0,0 +1,102 @@
+package org.briarproject.briar.android.sharing;
+
+import org.briarproject.bramble.api.connection.ConnectionRegistry;
+import org.briarproject.bramble.api.contact.ContactId;
+import org.briarproject.bramble.api.event.Event;
+import org.briarproject.bramble.api.event.EventBus;
+import org.briarproject.bramble.api.event.EventListener;
+import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
+import org.briarproject.bramble.api.plugin.event.ContactConnectedEvent;
+import org.briarproject.bramble.api.plugin.event.ContactDisconnectedEvent;
+
+import java.util.Collection;
+import java.util.HashSet;
+import java.util.Set;
+
+import javax.inject.Inject;
+
+import androidx.annotation.UiThread;
+import androidx.lifecycle.LiveData;
+import androidx.lifecycle.MutableLiveData;
+
+@NotNullByDefault
+public class SharingControllerImpl implements SharingController, EventListener {
+
+	private final EventBus eventBus;
+	private final ConnectionRegistry connectionRegistry;
+
+	// UI thread
+	private final Set<ContactId> contacts = new HashSet<>();
+	private final MutableLiveData<SharingInfo> sharingInfo =
+			new MutableLiveData<>();
+
+	@Inject
+	SharingControllerImpl(EventBus eventBus,
+			ConnectionRegistry connectionRegistry) {
+		this.eventBus = eventBus;
+		this.connectionRegistry = connectionRegistry;
+		eventBus.addListener(this);
+	}
+
+	@Override
+	public void onCleared() {
+		eventBus.removeListener(this);
+	}
+
+	@Override
+	public void eventOccurred(Event e) {
+		if (e instanceof ContactConnectedEvent) {
+			setConnected(((ContactConnectedEvent) e).getContactId());
+		} else if (e instanceof ContactDisconnectedEvent) {
+			setConnected(((ContactDisconnectedEvent) e).getContactId());
+		}
+	}
+
+	@UiThread
+	private void setConnected(ContactId c) {
+		if (contacts.contains(c)) {
+			updateLiveData();
+		}
+	}
+
+	@UiThread
+	private void updateLiveData() {
+		int online = getOnlineCount();
+		sharingInfo.setValue(new SharingInfo(contacts.size(), online));
+	}
+
+	private int getOnlineCount() {
+		int online = 0;
+		for (ContactId c : contacts) {
+			if (connectionRegistry.isConnected(c)) online++;
+		}
+		return online;
+	}
+
+	@UiThread
+	@Override
+	public void addAll(Collection<ContactId> c) {
+		contacts.addAll(c);
+		updateLiveData();
+	}
+
+	@UiThread
+	@Override
+	public void add(ContactId c) {
+		contacts.add(c);
+		updateLiveData();
+	}
+
+	@UiThread
+	@Override
+	public void remove(ContactId c) {
+		contacts.remove(c);
+		updateLiveData();
+	}
+
+	@Override
+	public LiveData<SharingInfo> getSharingInfo() {
+		return sharingInfo;
+	}
+
+}

briar-android/src/main/java/org/briarproject/briar/android/sharing/SharingModule.java

@@ -9,36 +9,47 @@ import dagger.Provides;
 @Module
 public class SharingModule {
 
-	@ActivityScope
-	@Provides
-	ShareForumController provideShareForumController(
-			ShareForumControllerImpl shareForumController) {
-		return shareForumController;
+	@Module
+	@Deprecated
+	public static class SharingLegacyModule {
+
+		@ActivityScope
+		@Provides
+		ShareForumController provideShareForumController(
+				ShareForumControllerImpl shareForumController) {
+			return shareForumController;
+		}
+
+		@ActivityScope
+		@Provides
+		BlogInvitationController provideInvitationBlogController(
+				BaseActivity activity,
+				BlogInvitationControllerImpl blogInvitationController) {
+			activity.addLifecycleController(blogInvitationController);
+			return blogInvitationController;
+		}
+
+		@ActivityScope
+		@Provides
+		ForumInvitationController provideInvitationForumController(
+				BaseActivity activity,
+				ForumInvitationControllerImpl forumInvitationController) {
+			activity.addLifecycleController(forumInvitationController);
+			return forumInvitationController;
+		}
+
+		@ActivityScope
+		@Provides
+		ShareBlogController provideShareBlogController(
+				ShareBlogControllerImpl shareBlogController) {
+			return shareBlogController;
+		}
 	}
 
-	@ActivityScope
 	@Provides
-	BlogInvitationController provideInvitationBlogController(
-			BaseActivity activity,
-			BlogInvitationControllerImpl blogInvitationController) {
-		activity.addLifecycleController(blogInvitationController);
-		return blogInvitationController;
-	}
-
-	@ActivityScope
-	@Provides
-	ForumInvitationController provideInvitationForumController(
-			BaseActivity activity,
-			ForumInvitationControllerImpl forumInvitationController) {
-		activity.addLifecycleController(forumInvitationController);
-		return forumInvitationController;
-	}
-
-	@ActivityScope
-	@Provides
-	ShareBlogController provideShareBlogController(
-			ShareBlogControllerImpl shareBlogController) {
-		return shareBlogController;
+	SharingController provideSharingController(
+			SharingControllerImpl sharingController) {
+		return sharingController;
 	}
 
 }

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

@@ -1,54 +0,0 @@
-package org.briarproject.briar.android.threaded;
-
-import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
-import org.briarproject.bramble.api.sync.MessageId;
-import org.briarproject.briar.api.client.MessageTree;
-import org.briarproject.briar.api.client.MessageTree.MessageNode;
-import org.briarproject.briar.client.MessageTreeImpl;
-
-import java.util.ArrayList;
-import java.util.Collection;
-import java.util.Iterator;
-import java.util.List;
-
-import androidx.annotation.UiThread;
-
-@UiThread
-@NotNullByDefault
-public class NestedTreeList<T extends MessageNode> implements Iterable<T> {
-
-	private final MessageTree<T> tree = new MessageTreeImpl<>();
-	private List<T> depthFirstCollection = new ArrayList<>();
-
-	public void addAll(Collection<T> collection) {
-		tree.add(collection);
-		depthFirstCollection = new ArrayList<>(tree.depthFirstOrder());
-	}
-
-	public void add(T elem) {
-		tree.add(elem);
-		depthFirstCollection = new ArrayList<>(tree.depthFirstOrder());
-	}
-
-	public void clear() {
-		tree.clear();
-		depthFirstCollection.clear();
-	}
-
-	public T get(int index) {
-		return depthFirstCollection.get(index);
-	}
-
-	public int size() {
-		return depthFirstCollection.size();
-	}
-
-	public boolean contains(MessageId m) {
-		return tree.contains(m);
-	}
-
-	@Override
-	public Iterator<T> iterator() {
-		return depthFirstCollection.iterator();
-	}
-}

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

@@ -99,4 +99,14 @@ public abstract class ThreadItem implements MessageNode {
 		return highlighted;
 	}
 
+	@Override
+	public int hashCode() {
+		return messageId.hashCode();
+	}
+
+	@Override
+	public boolean equals(@Nullable Object o) {
+		return o instanceof ThreadItem &&
+				messageId.equals(((ThreadItem) o).messageId);
+	}
 }

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

@@ -4,39 +4,45 @@ import android.view.LayoutInflater;
 import android.view.View;
 import android.view.ViewGroup;
 
+import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
 import org.briarproject.bramble.api.sync.MessageId;
 import org.briarproject.briar.R;
 import org.briarproject.briar.android.util.ItemReturningAdapter;
-import org.briarproject.briar.android.util.VersionedAdapter;
-
-import java.util.Collection;
 
 import javax.annotation.Nullable;
 
 import androidx.annotation.NonNull;
 import androidx.annotation.UiThread;
+import androidx.recyclerview.widget.DiffUtil;
 import androidx.recyclerview.widget.LinearLayoutManager;
-import androidx.recyclerview.widget.RecyclerView;
+import androidx.recyclerview.widget.ListAdapter;
 
 import static androidx.recyclerview.widget.RecyclerView.NO_POSITION;
 
 @UiThread
+@NotNullByDefault
 public class ThreadItemAdapter<I extends ThreadItem>
-		extends RecyclerView.Adapter<BaseThreadItemViewHolder<I>>
-		implements VersionedAdapter, ItemReturningAdapter<I> {
+		extends ListAdapter<I, BaseThreadItemViewHolder<I>>
+		implements ItemReturningAdapter<I> {
 
 	static final int UNDEFINED = -1;
 
-	protected final NestedTreeList<I> items = new NestedTreeList<>();
 	private final ThreadItemListener<I> listener;
-	private final LinearLayoutManager layoutManager;
 
-	private volatile int revision = 0;
+	public ThreadItemAdapter(ThreadItemListener<I> listener) {
+		super(new DiffUtil.ItemCallback<I>() {
+			@Override
+			public boolean areItemsTheSame(I a, I b) {
+				return a.equals(b);
+			}
 
-	public ThreadItemAdapter(ThreadItemListener<I> listener,
-			LinearLayoutManager layoutManager) {
+			@Override
+			public boolean areContentsTheSame(I a, I b) {
+				return a.isHighlighted() == b.isHighlighted() &&
+						a.isRead() == b.isRead();
+			}
+		});
 		this.listener = listener;
-		this.layoutManager = layoutManager;
 	}
 
 	@NonNull
@@ -51,76 +57,27 @@ public class ThreadItemAdapter<I extends ThreadItem>
 	@Override
 	public void onBindViewHolder(@NonNull BaseThreadItemViewHolder<I> ui,
 			int position) {
-		I item = items.get(position);
+		I item = getItem(position);
 		ui.bind(item, listener);
 	}
 
-	@Override
-	public int getItemCount() {
-		return items.size();
-	}
-
-	@Override
-	public int getRevision() {
-		return revision;
-	}
-
-	@Override
-	public void incrementRevision() {
-		revision++;
-	}
-
-	void setItemWithIdVisible(MessageId messageId) {
-		int pos = 0;
-		for (I item : items) {
-			if (item.getId().equals(messageId)) {
-				layoutManager.scrollToPosition(pos);
-				break;
-			}
-			pos++;
-		}
-	}
-
-	public void setItems(Collection<I> items) {
-		this.items.clear();
-		this.items.addAll(items);
-		notifyDataSetChanged();
-	}
-
-	public void add(I item) {
-		items.add(item);
-		notifyItemInserted(findItemPosition(item));
-	}
-
-	@Nullable
-	public I getItemAt(int position) {
-		if (position == NO_POSITION || position >= items.size()) {
-			return null;
-		}
-		return items.get(position);
-	}
-
-	protected int findItemPosition(@Nullable I item) {
-		for (int i = 0; i < items.size(); i++) {
-			if (items.get(i).equals(item)) return i;
+	int findItemPosition(MessageId id) {
+		for (int i = 0; i < getItemCount(); i++) {
+			if (id.equals(getItem(i).getId())) return i;
 		}
 		return NO_POSITION; // Not found
 	}
 
-	boolean contains(MessageId m) {
-		return items.contains(m);
-	}
-
 	/**
 	 * Highlights the item with the given {@link MessageId}
 	 * and disables the highlight for a previously highlighted item, if any.
-	 *
+	 * <p>
 	 * Only one item can be highlighted at a time.
 	 */
 	void setHighlightedItem(@Nullable MessageId id) {
-		for (int i = 0; i < items.size(); i++) {
-			I item = items.get(i);
-			if (id != null && item.getId().equals(id)) {
+		for (int i = 0; i < getItemCount(); i++) {
+			I item = getItem(i);
+			if (item.getId().equals(id)) {
 				item.setHighlighted(true);
 				notifyItemChanged(i, item);
 			} else if (item.isHighlighted()) {
@@ -132,20 +89,27 @@ public class ThreadItemAdapter<I extends ThreadItem>
 
 	@Nullable
 	I getHighlightedItem() {
-		for (I i : items) {
-			if (i.isHighlighted()) return i;
+		for (I item : getCurrentList()) {
+			if (item.isHighlighted()) return item;
 		}
 		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 < items.size(); i++) {
-			if (!items.get(i).isRead()) return i;
+		for (int i = positionBottom + 1; i < getItemCount(); i++) {
+			if (!getItem(i).isRead()) return i;
 		}
 		return NO_POSITION;
 	}
@@ -153,11 +117,11 @@ 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 < items.size(); i++) {
-			if (i < positionTop && !items.get(i).isRead()) {
+		for (int i = 0; i < getItemCount(); i++) {
+			if (i < positionTop && !getItem(i).isRead()) {
 				position = i;
 			} else if (i >= positionTop) {
 				return position;
@@ -166,6 +130,11 @@ public class ThreadItemAdapter<I extends ThreadItem>
 		return NO_POSITION;
 	}
 
+	@Override
+	public I getItemAt(int position) {
+		return getItem(position);
+	}
+
 	public interface ThreadItemListener<I> {
 		void onReplyClick(I item);
 	}

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

@@ -1,15 +0,0 @@
-package org.briarproject.briar.android.threaded;
-
-import org.briarproject.bramble.api.sync.MessageId;
-
-import java.util.List;
-
-import javax.annotation.Nullable;
-
-public interface ThreadItemList<I extends ThreadItem> extends List<I> {
-
-	@Nullable
-	MessageId getFirstVisibleItemId();
-
-	void setFirstVisibleId(@Nullable MessageId bottomVisibleItemId);
-}

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

@@ -1,23 +0,0 @@
-package org.briarproject.briar.android.threaded;
-
-import org.briarproject.bramble.api.sync.MessageId;
-
-import java.util.ArrayList;
-
-import javax.annotation.Nullable;
-
-public class ThreadItemListImpl<I extends ThreadItem> extends ArrayList<I>
-		implements ThreadItemList<I> {
-
-	private MessageId bottomVisibleItemId;
-
-	@Override
-	public MessageId getFirstVisibleItemId() {
-		return bottomVisibleItemId;
-	}
-
-	@Override
-	public void setFirstVisibleId(@Nullable MessageId bottomVisibleItemId) {
-		this.bottomVisibleItemId = bottomVisibleItemId;
-	}
-}

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

@@ -2,25 +2,18 @@ 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;
 
-import org.briarproject.bramble.api.contact.ContactId;
-import org.briarproject.bramble.api.db.DbException;
 import org.briarproject.bramble.api.nullsafety.MethodsNotNullByDefault;
 import org.briarproject.bramble.api.nullsafety.ParametersNotNullByDefault;
 import org.briarproject.bramble.api.sync.GroupId;
 import org.briarproject.bramble.api.sync.MessageId;
 import org.briarproject.briar.R;
 import org.briarproject.briar.android.activity.BriarActivity;
-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.sharing.SharingController.SharingInfo;
 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;
 import org.briarproject.briar.android.view.TextInputView;
@@ -28,18 +21,13 @@ import org.briarproject.briar.android.view.TextSendController;
 import org.briarproject.briar.android.view.TextSendController.SendListener;
 import org.briarproject.briar.android.view.UnreadMessageButton;
 import org.briarproject.briar.api.attachment.AttachmentHeader;
-import org.briarproject.briar.api.client.NamedGroup;
 
-import java.util.Collection;
 import java.util.List;
-import java.util.logging.Logger;
 
 import javax.annotation.Nullable;
-import javax.inject.Inject;
 
 import androidx.annotation.CallSuper;
 import androidx.annotation.StringRes;
-import androidx.annotation.UiThread;
 import androidx.appcompat.app.ActionBar;
 import androidx.recyclerview.widget.LinearLayoutManager;
 
@@ -48,32 +36,19 @@ import static org.briarproject.bramble.util.StringUtils.isNullOrEmpty;
 
 @MethodsNotNullByDefault
 @ParametersNotNullByDefault
-public abstract class ThreadListActivity<G extends NamedGroup, I extends ThreadItem, A extends ThreadItemAdapter<I>>
-		extends BriarActivity
-		implements ThreadListListener<I>, SendListener, SharingListener,
-		ThreadItemListener<I>, ThreadListDataSource {
+public abstract class ThreadListActivity<I extends ThreadItem, A extends ThreadItemAdapter<I>>
+		extends BriarActivity implements SendListener, ThreadItemListener<I> {
 
-	protected static final String KEY_REPLY_ID = "replyId";
-
-	private static final Logger LOG =
-			Logger.getLogger(ThreadListActivity.class.getName());
-
-	protected A adapter;
-	private ThreadScrollListener<I> scrollListener;
+	protected final A adapter = createAdapter();
+	protected abstract ThreadListViewModel<I> getViewModel();
+	protected abstract A createAdapter();
 	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<G, I> getController();
-
-	@Inject
-	protected SharingController sharingController;
+	private LinearLayoutManager layoutManager;
+	private ThreadScrollListener<I> scrollListener;
 
 	@CallSuper
 	@Override
@@ -86,7 +61,8 @@ public abstract class ThreadListActivity<G extends NamedGroup, I extends ThreadI
 		byte[] b = i.getByteArrayExtra(GROUP_ID);
 		if (b == null) throw new IllegalStateException("No GroupId in intent.");
 		groupId = new GroupId(b);
-		getController().setGroupId(groupId);
+		ThreadListViewModel<I> viewModel = getViewModel();
+		viewModel.setGroupId(groupId);
 
 		textInput = findViewById(R.id.text_input_container);
 		sendController = new TextSendController(textInput, this, false);
@@ -100,131 +76,41 @@ public abstract class ThreadListActivity<G extends NamedGroup, I 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(),
+		scrollListener = new ThreadScrollListener<>(adapter, viewModel,
 				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);
-		}
+		viewModel.getItems().observe(this, result -> result
+				.onError(this::handleException)
+				.onSuccess(this::displayItems)
+		);
 
-		sharingController.setSharingListener(this);
-		loadSharingContacts();
-	}
+		viewModel.getSharingInfo().observe(this, this::setToolbarSubTitle);
 
-	@Override
-	@Nullable
-	public MessageId getFirstVisibleMessageId() {
-		if (layoutManager != null && adapter != null) {
-			int position =
-					layoutManager.findFirstVisibleItemPosition();
-			I i = adapter.getItemAt(position);
-			return i == null ? null : i.getId();
-		}
-		return null;
-	}
-
-	protected abstract A createAdapter(LinearLayoutManager layoutManager);
-
-	protected void loadNamedGroup() {
-		getController().loadNamedGroup(
-				new UiResultExceptionHandler<G, DbException>(this) {
-					@Override
-					public void onResultUi(G groupItem) {
-						onNamedGroupLoaded(groupItem);
-					}
-
-					@Override
-					public void onExceptionUi(DbException exception) {
-						handleException(exception);
-					}
-				});
-	}
-
-	@UiThread
-	protected abstract void onNamedGroupLoaded(G groupItem);
-
-	protected void loadItems() {
-		int revision = adapter.getRevision();
-		getController().loadItems(
-				new UiResultExceptionHandler<ThreadItemList<I>, DbException>(
-						this) {
-					@Override
-					public void onResultUi(ThreadItemList<I> items) {
-						if (revision == adapter.getRevision()) {
-							adapter.incrementRevision();
-							if (items.isEmpty()) {
-								list.showData();
-							} else {
-								displayItems(items);
-								updateTextInput();
-							}
-						} else {
-							LOG.info("Concurrent update, reloading");
-							loadItems();
-						}
-					}
-
-					@Override
-					public void onExceptionUi(DbException exception) {
-						handleException(exception);
-					}
-				});
-	}
-
-	private void displayItems(ThreadItemList<I> items) {
-		adapter.setItems(items);
-		MessageId messageId = items.getFirstVisibleItemId();
-		if (messageId != null)
-			adapter.setItemWithIdVisible(messageId);
-		list.showData();
-		if (layoutManagerState == null) {
-			list.scrollToPosition(0);  // Scroll to the top
-		} else {
-			layoutManager.onRestoreInstanceState(layoutManagerState);
-		}
-	}
-
-	protected void loadSharingContacts() {
-		getController().loadSharingContacts(
-				new UiResultExceptionHandler<Collection<ContactId>, DbException>(
-						this) {
-					@Override
-					public void onResultUi(Collection<ContactId> contacts) {
-						sharingController.addAll(contacts);
-						int online = sharingController.getOnlineCount();
-						setToolbarSubTitle(contacts.size(), online);
-					}
-
-					@Override
-					public void onExceptionUi(DbException exception) {
-						handleException(exception);
-					}
-				});
+		viewModel.getGroupRemoved().observe(this, removed -> {
+			if (removed) supportFinishAfterTransition();
+		});
 	}
 
 	@CallSuper
 	@Override
 	public void onStart() {
 		super.onStart();
-		sharingController.onStart();
-		loadItems();
+		getViewModel().blockAndClearNotifications();
 		list.startPeriodicUpdate();
 	}
 
@@ -232,91 +118,98 @@ public abstract class ThreadListActivity<G extends NamedGroup, I extends ThreadI
 	@Override
 	public void onStop() {
 		super.onStop();
-		sharingController.onStop();
+		getViewModel().unblockNotifications();
 		list.stopPeriodicUpdate();
 	}
 
-	@Override
-	protected void onSaveInstanceState(Bundle outState) {
-		super.onSaveInstanceState(outState);
-		if (layoutManager != null) {
-			layoutManagerState = layoutManager.onSaveInstanceState();
-			outState.putParcelable("layoutManager", layoutManagerState);
-		}
-		if (replyId != null) {
-			outState.putByteArray(KEY_REPLY_ID, replyId.getBytes());
-		}
-	}
-
-	@Override
-	protected void onRestoreInstanceState(Bundle savedInstanceState) {
-		super.onRestoreInstanceState(savedInstanceState);
-		layoutManagerState = savedInstanceState.getParcelable("layoutManager");
-	}
-
 	@Override
 	public boolean onOptionsItemSelected(MenuItem item) {
-		switch (item.getItemId()) {
-			case android.R.id.home:
-				supportFinishAfterTransition();
-				return true;
-			default:
-				return super.onOptionsItemSelected(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;
+			getViewModel().setReplyId(null);
 			updateTextInput();
 		} else {
 			super.onBackPressed();
 		}
 	}
 
+	@Override
+	protected void onDestroy() {
+		super.onDestroy();
+		// store list position, so we can restore it when coming back here
+		if (layoutManager != null && adapter != null) {
+			MessageId id = adapter.getFirstVisibleMessageId(layoutManager);
+			getViewModel().storeMessageId(id);
+		}
+	}
+
+	protected void displayItems(List<I> items) {
+		if (items.isEmpty()) {
+			list.showData();
+		} else {
+			adapter.submitList(items, () -> {
+				// do stuff *after* list had been updated
+				scrollAfterListCommitted();
+				updateTextInput();
+			});
+		}
+	}
+
+	/**
+	 * Scrolls to the first visible item last time the activity was open,
+	 * if one exists and this is the first time, the list gets displayed.
+	 * Or scrolls to a locally added item that has just been added to the list.
+	 */
+	private void scrollAfterListCommitted() {
+		MessageId restoredFirstVisibleItemId =
+				getViewModel().getAndResetRestoredMessageId();
+		MessageId scrollToItem =
+				getViewModel().getAndResetScrollToItem();
+		if (restoredFirstVisibleItemId != null) {
+			scrollToItemAtTop(restoredFirstVisibleItemId);
+		} else if (scrollToItem != null) {
+			scrollToItemAtTop(scrollToItem);
+		}
+		scrollListener.updateUnreadButtons(layoutManager);
+	}
+
 	@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()) {
-			scrollToItemAtTop(item);
+			scrollToItemAtTop(item.getId());
 		} else {
 			// wait with scrolling until keyboard opened
 			textInput.setOnKeyboardShownListener(() -> {
-				scrollToItemAtTop(item);
+				scrollToItemAtTop(item.getId());
 				textInput.setOnKeyboardShownListener(null);
 			});
 		}
 	}
 
-	@Override
-	public void onSharingInfoUpdated(int total, int online) {
-		setToolbarSubTitle(total, online);
-	}
-
-	@Override
-	public void onInvitationAccepted(ContactId c) {
-		sharingController.add(c);
-		setToolbarSubTitle(sharingController.getTotalCount(),
-				sharingController.getOnlineCount());
-	}
-
-	protected void setToolbarSubTitle(int total, int online) {
+	protected void setToolbarSubTitle(SharingInfo sharingInfo) {
 		ActionBar actionBar = getSupportActionBar();
 		if (actionBar != null) {
-			actionBar.setSubtitle(
-					getString(R.string.shared_with, total, online));
+			actionBar.setSubtitle(getString(R.string.shared_with,
+					sharingInfo.total, sharingInfo.online));
 		}
 	}
 
-	private void scrollToItemAtTop(I item) {
-		int position = adapter.findItemPosition(item);
+	private void scrollToItemAtTop(MessageId messageId) {
+		int position = adapter.findItemPosition(messageId);
 		if (position != NO_POSITION) {
-			layoutManager
-					.scrollToPositionWithOffset(position, 0);
+			layoutManager.scrollToPositionWithOffset(position, 0);
 		}
 	}
 
@@ -327,6 +220,7 @@ public abstract class ThreadListActivity<G extends NamedGroup, I extends ThreadI
 	}
 
 	private void updateTextInput() {
+		MessageId replyId = getViewModel().getReplyId();
 		if (replyId != null) {
 			textInput.setHint(R.string.forum_message_reply_hint);
 			textInput.showSoftKeyboard();
@@ -341,54 +235,14 @@ public abstract class ThreadListActivity<G extends NamedGroup, I extends ThreadI
 			List<AttachmentHeader> headers) {
 		if (isNullOrEmpty(text)) throw new AssertionError();
 
-		I replyItem = adapter.getHighlightedItem();
-		UiResultExceptionHandler<I, DbException> handler =
-				new UiResultExceptionHandler<I, DbException>(this) {
-					@Override
-					public void onResultUi(I result) {
-						addItem(result, true);
-					}
-
-					@Override
-					public void onExceptionUi(DbException exception) {
-						handleException(exception);
-					}
-				};
-		getController().createAndStoreMessage(text, replyItem, handler);
+		MessageId replyId = getViewModel().getReplyId();
+		getViewModel().createAndStoreMessage(text, replyId);
 		textInput.hideSoftKeyboard();
 		textInput.clearText();
-		replyId = null;
+		getViewModel().setReplyId(null);
 		updateTextInput();
 	}
 
 	protected abstract int getMaxTextLength();
 
-	@Override
-	public void onItemReceived(I item) {
-		addItem(item, false);
-	}
-
-	@Override
-	public void onGroupRemoved() {
-		supportFinishAfterTransition();
-	}
-
-	private void addItem(I item, boolean isLocal) {
-		adapter.incrementRevision();
-		MessageId parent = item.getParentId();
-		if (parent != null && !adapter.contains(parent)) {
-			// We've incremented the adapter's revision, so the item will be
-			// loaded when its parent has been loaded
-			LOG.info("Ignoring item with missing parent");
-			return;
-		}
-		adapter.add(item);
-
-		if (isLocal) {
-			scrollToItemAtTop(item);
-		} else {
-			scrollListener.updateUnreadButtons(layoutManager);
-		}
-	}
-
 }

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

@@ -1,60 +0,0 @@
-package org.briarproject.briar.android.threaded;
-
-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.ExceptionHandler;
-import org.briarproject.briar.android.controller.handler.ResultExceptionHandler;
-import org.briarproject.briar.api.client.NamedGroup;
-
-import java.util.Collection;
-
-import javax.annotation.Nullable;
-
-import androidx.annotation.UiThread;
-
-@NotNullByDefault
-public interface ThreadListController<G extends NamedGroup, I extends ThreadItem>
-		extends ActivityLifecycleController {
-
-	void setGroupId(GroupId groupId);
-
-	void loadNamedGroup(ResultExceptionHandler<G, DbException> handler);
-
-	void loadSharingContacts(
-			ResultExceptionHandler<Collection<ContactId>, DbException> handler);
-
-	void loadItems(
-			ResultExceptionHandler<ThreadItemList<I>, DbException> handler);
-
-	void markItemRead(I item);
-
-	void markItemsRead(Collection<I> items);
-
-	void createAndStoreMessage(String text, @Nullable I parentItem,
-			ResultExceptionHandler<I, DbException> handler);
-
-	void deleteNamedGroup(ExceptionHandler<DbException> handler);
-
-	interface ThreadListListener<I> extends ThreadListDataSource {
-
-		@UiThread
-		void onItemReceived(I item);
-
-		@UiThread
-		void onGroupRemoved();
-
-		@UiThread
-		void onInvitationAccepted(ContactId c);
-	}
-
-	interface ThreadListDataSource {
-
-		@UiThread @Nullable
-		MessageId getFirstVisibleMessageId();
-	}
-
-}

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

@@ -1,273 +0,0 @@
-package org.briarproject.briar.android.threaded;
-
-import android.app.Activity;
-
-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.event.Event;
-import org.briarproject.bramble.api.event.EventBus;
-import org.briarproject.bramble.api.event.EventListener;
-import org.briarproject.bramble.api.identity.IdentityManager;
-import org.briarproject.bramble.api.lifecycle.LifecycleManager;
-import org.briarproject.bramble.api.nullsafety.MethodsNotNullByDefault;
-import org.briarproject.bramble.api.nullsafety.ParametersNotNullByDefault;
-import org.briarproject.bramble.api.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.android.controller.handler.ExceptionHandler;
-import org.briarproject.briar.android.controller.handler.ResultExceptionHandler;
-import org.briarproject.briar.android.threaded.ThreadListController.ThreadListListener;
-import org.briarproject.briar.api.android.AndroidNotificationManager;
-import org.briarproject.briar.api.client.MessageTracker;
-import org.briarproject.briar.api.client.NamedGroup;
-import org.briarproject.briar.api.client.PostHeader;
-import org.briarproject.briar.api.client.ThreadedMessage;
-
-import java.util.Collection;
-import java.util.Collections;
-import java.util.Map;
-import java.util.concurrent.ConcurrentHashMap;
-import java.util.concurrent.Executor;
-import java.util.logging.Logger;
-
-import androidx.annotation.CallSuper;
-
-import static java.util.logging.Level.INFO;
-import static java.util.logging.Level.WARNING;
-import static org.briarproject.bramble.util.LogUtils.logDuration;
-import static org.briarproject.bramble.util.LogUtils.logException;
-import static org.briarproject.bramble.util.LogUtils.now;
-
-@MethodsNotNullByDefault
-@ParametersNotNullByDefault
-public abstract class ThreadListControllerImpl<G extends NamedGroup, I extends ThreadItem, H extends PostHeader, M extends ThreadedMessage, L extends ThreadListListener<I>>
-		extends DbControllerImpl
-		implements ThreadListController<G, I>, EventListener {
-
-	private static final Logger LOG =
-			Logger.getLogger(ThreadListControllerImpl.class.getName());
-
-	private final EventBus eventBus;
-	private final MessageTracker messageTracker;
-	private final Map<MessageId, String> textCache = new ConcurrentHashMap<>();
-
-	private volatile GroupId groupId;
-
-	protected final IdentityManager identityManager;
-	protected final AndroidNotificationManager notificationManager;
-	protected final Executor cryptoExecutor;
-	protected final Clock clock;
-
-	// UI thread
-	protected L listener;
-
-	protected ThreadListControllerImpl(@DatabaseExecutor Executor dbExecutor,
-			LifecycleManager lifecycleManager, IdentityManager identityManager,
-			@CryptoExecutor Executor cryptoExecutor, EventBus eventBus,
-			Clock clock, AndroidNotificationManager notificationManager,
-			MessageTracker messageTracker) {
-		super(dbExecutor, lifecycleManager);
-		this.identityManager = identityManager;
-		this.cryptoExecutor = cryptoExecutor;
-		this.notificationManager = notificationManager;
-		this.clock = clock;
-		this.eventBus = eventBus;
-		this.messageTracker = messageTracker;
-	}
-
-	@Override
-	public void setGroupId(GroupId groupId) {
-		this.groupId = groupId;
-	}
-
-	@CallSuper
-	@SuppressWarnings("unchecked")
-	@Override
-	public void onActivityCreate(Activity activity) {
-		listener = (L) activity;
-	}
-
-	@CallSuper
-	@Override
-	public void onActivityStart() {
-		notificationManager.blockNotification(getGroupId());
-		eventBus.addListener(this);
-	}
-
-	@CallSuper
-	@Override
-	public void onActivityStop() {
-		notificationManager.unblockNotification(getGroupId());
-		eventBus.removeListener(this);
-	}
-
-	@Override
-	public void onActivityDestroy() {
-		MessageId messageId = listener.getFirstVisibleMessageId();
-		if (messageId != null) {
-			dbExecutor.execute(() -> {
-				try {
-					messageTracker.storeMessageId(groupId, messageId);
-				} catch (DbException e) {
-					logException(LOG, WARNING, e);
-				}
-			});
-		}
-	}
-
-	@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
-	public void loadNamedGroup(
-			ResultExceptionHandler<G, DbException> handler) {
-		checkGroupId();
-		runOnDbThread(() -> {
-			try {
-				long start = now();
-				G groupItem = loadNamedGroup();
-				logDuration(LOG, "Loading group", start);
-				handler.onResult(groupItem);
-			} catch (DbException e) {
-				logException(LOG, WARNING, e);
-				handler.onException(e);
-			}
-		});
-	}
-
-	@DatabaseExecutor
-	protected abstract G loadNamedGroup() throws DbException;
-
-	@Override
-	public void loadItems(
-			ResultExceptionHandler<ThreadItemList<I>, DbException> handler) {
-		checkGroupId();
-		runOnDbThread(() -> {
-			try {
-				// Load headers
-				long start = now();
-				Collection<H> headers = loadHeaders();
-				logDuration(LOG, "Loading headers", start);
-
-				// Load bodies into cache
-				start = now();
-				for (H header : headers) {
-					if (!textCache.containsKey(header.getId())) {
-						textCache.put(header.getId(),
-								loadMessageText(header));
-					}
-				}
-				logDuration(LOG, "Loading bodies", start);
-
-				// Build and hand over items
-				handler.onResult(buildItems(headers));
-			} catch (DbException e) {
-				logException(LOG, WARNING, e);
-				handler.onException(e);
-			}
-		});
-	}
-
-	@DatabaseExecutor
-	protected abstract Collection<H> loadHeaders() throws DbException;
-
-	@DatabaseExecutor
-	protected abstract String loadMessageText(H header) throws DbException;
-
-	@Override
-	public void markItemRead(I item) {
-		markItemsRead(Collections.singletonList(item));
-	}
-
-	@Override
-	public void markItemsRead(Collection<I> items) {
-		runOnDbThread(() -> {
-			try {
-				long start = now();
-				for (I i : items) {
-					markRead(i.getId());
-				}
-				logDuration(LOG, "Marking read", start);
-			} catch (DbException e) {
-				logException(LOG, WARNING, e);
-			}
-		});
-	}
-
-	@DatabaseExecutor
-	protected abstract void markRead(MessageId id) throws DbException;
-
-	protected void storePost(M msg, String text,
-			ResultExceptionHandler<I, DbException> resultHandler) {
-		runOnDbThread(() -> {
-			try {
-				long start = now();
-				H header = addLocalMessage(msg);
-				textCache.put(msg.getMessage().getId(), text);
-				logDuration(LOG, "Storing message", start);
-				resultHandler.onResult(buildItem(header, text));
-			} catch (DbException e) {
-				logException(LOG, WARNING, e);
-				resultHandler.onException(e);
-			}
-		});
-	}
-
-	@DatabaseExecutor
-	protected abstract H addLocalMessage(M message) throws DbException;
-
-	@Override
-	public void deleteNamedGroup(ExceptionHandler<DbException> handler) {
-		runOnDbThread(() -> {
-			try {
-				long start = now();
-				G groupItem = loadNamedGroup();
-				deleteNamedGroup(groupItem);
-				logDuration(LOG, "Removing group", start);
-			} catch (DbException e) {
-				logException(LOG, WARNING, e);
-				handler.onException(e);
-			}
-		});
-	}
-
-	@DatabaseExecutor
-	protected abstract void deleteNamedGroup(G groupItem) throws DbException;
-
-	private ThreadItemList<I> buildItems(Collection<H> headers)
-			throws DbException {
-		ThreadItemList<I> items = new ThreadItemListImpl<>();
-		for (H h : headers) {
-			items.add(buildItem(h, textCache.get(h.getId())));
-		}
-		MessageId msgId = messageTracker.loadStoredMessageId(groupId);
-		if (LOG.isLoggable(INFO))
-			LOG.info("Loaded last top visible message id " + msgId);
-		items.setFirstVisibleId(msgId);
-		return items;
-	}
-
-	protected abstract I buildItem(H header, String text);
-
-	protected GroupId getGroupId() {
-		checkGroupId();
-		return groupId;
-	}
-
-	private void checkGroupId() {
-		if (groupId == null) throw new IllegalStateException();
-	}
-
-}

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

@@ -0,0 +1,256 @@
+package org.briarproject.briar.android.threaded;
+
+import android.app.Application;
+
+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.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;
+import org.briarproject.bramble.api.lifecycle.LifecycleManager;
+import org.briarproject.bramble.api.nullsafety.MethodsNotNullByDefault;
+import org.briarproject.bramble.api.nullsafety.ParametersNotNullByDefault;
+import org.briarproject.bramble.api.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.sharing.SharingController;
+import org.briarproject.briar.android.sharing.SharingController.SharingInfo;
+import org.briarproject.briar.android.viewmodel.DbViewModel;
+import org.briarproject.briar.android.viewmodel.LiveResult;
+import org.briarproject.briar.api.android.AndroidNotificationManager;
+import org.briarproject.briar.api.client.MessageTracker;
+import org.briarproject.briar.api.client.MessageTree;
+import org.briarproject.briar.client.MessageTreeImpl;
+
+import java.util.List;
+import java.util.concurrent.Executor;
+import java.util.concurrent.atomic.AtomicReference;
+import java.util.logging.Logger;
+
+import javax.annotation.Nullable;
+
+import androidx.annotation.CallSuper;
+import androidx.annotation.UiThread;
+import androidx.lifecycle.LiveData;
+import androidx.lifecycle.MutableLiveData;
+
+import static java.util.Objects.requireNonNull;
+import static java.util.logging.Level.INFO;
+import static java.util.logging.Level.WARNING;
+import static java.util.logging.Logger.getLogger;
+import static org.briarproject.bramble.util.LogUtils.logException;
+
+@MethodsNotNullByDefault
+@ParametersNotNullByDefault
+public abstract class ThreadListViewModel<I extends ThreadItem>
+		extends DbViewModel implements EventListener {
+
+	private static final Logger LOG =
+			getLogger(ThreadListViewModel.class.getName());
+
+	protected final IdentityManager identityManager;
+	protected final AndroidNotificationManager notificationManager;
+	protected final SharingController sharingController;
+	protected final Executor cryptoExecutor;
+	protected final Clock clock;
+	private final MessageTracker messageTracker;
+	private final EventBus eventBus;
+
+	// UIThread
+	private final MessageTree<I> messageTree = new MessageTreeImpl<>();
+	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;
+	/**
+	 * Stored list position. Needs to be loaded and set before the list itself.
+	 */
+	private final AtomicReference<MessageId> storedMessageId =
+			new AtomicReference<>();
+
+	public ThreadListViewModel(Application application,
+			@DatabaseExecutor Executor dbExecutor,
+			LifecycleManager lifecycleManager,
+			TransactionManager db,
+			AndroidExecutor androidExecutor,
+			IdentityManager identityManager,
+			AndroidNotificationManager notificationManager,
+			SharingController sharingController,
+			@CryptoExecutor Executor cryptoExecutor,
+			Clock clock,
+			MessageTracker messageTracker,
+			EventBus eventBus) {
+		super(application, dbExecutor, lifecycleManager, db, androidExecutor);
+		this.identityManager = identityManager;
+		this.notificationManager = notificationManager;
+		this.cryptoExecutor = cryptoExecutor;
+		this.clock = clock;
+		this.sharingController = sharingController;
+		this.messageTracker = messageTracker;
+		this.eventBus = eventBus;
+		this.eventBus.addListener(this);
+	}
+
+	@Override
+	protected void onCleared() {
+		super.onCleared();
+		eventBus.removeListener(this);
+		sharingController.onCleared();
+	}
+
+	/**
+	 * Needs to be called right after initialization,
+	 * before calling any other methods.
+	 */
+	public final void setGroupId(GroupId groupId) {
+		boolean needsInitialLoad = this.groupId == null;
+		this.groupId = groupId;
+		if (needsInitialLoad) performInitialLoad();
+	}
+
+	@CallSuper
+	protected void performInitialLoad() {
+		// load stored MessageId (last list position) before the list itself
+		loadStoredMessageId();
+		loadItems();
+		loadSharingContacts();
+	}
+
+	protected abstract void clearNotifications();
+
+	void blockAndClearNotifications() {
+		notificationManager.blockNotification(groupId);
+		clearNotifications();
+	}
+
+	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 {
+				storedMessageId
+						.set(messageTracker.loadStoredMessageId(groupId));
+				if (LOG.isLoggable(INFO)) {
+					LOG.info("Loaded last top visible message id " +
+							storedMessageId);
+				}
+			} catch (DbException e) {
+				logException(LOG, WARNING, e);
+			}
+		});
+	}
+
+	public abstract void loadItems();
+
+	public abstract void createAndStoreMessage(String text,
+			@Nullable MessageId parentMessageId);
+
+	/**
+	 * Loads the ContactIds of all contacts the group is shared with
+	 * and adds them to {@link SharingController}.
+	 */
+	protected abstract void loadSharingContacts();
+
+	@UiThread
+	protected void setItems(LiveResult<List<I>> items) {
+		if (items.hasError()) {
+			this.items.setValue(items);
+		} else {
+			messageTree.clear();
+			// not null, because hasError() is false
+			messageTree.add(requireNonNull(items.getResultOrNull()));
+			LiveResult<List<I>> result =
+					new LiveResult<>(messageTree.depthFirstOrder());
+			this.items.setValue(result);
+		}
+	}
+
+	/**
+	 * Add a remote item on the UI thread.
+	 *
+	 * @param scrollToItem whether the list will scroll to the newly added item
+	 */
+	@UiThread
+	protected void addItem(I item, boolean scrollToItem) {
+		messageTree.add(item);
+		if (scrollToItem) this.scrollToItem.set(item.getId());
+		items.setValue(new LiveResult<>(messageTree.depthFirstOrder()));
+	}
+
+	@UiThread
+	void setReplyId(@Nullable MessageId id) {
+		replyId = id;
+	}
+
+	@UiThread
+	@Nullable
+	MessageId getReplyId() {
+		return replyId;
+	}
+
+	void storeMessageId(@Nullable MessageId messageId) {
+		if (messageId != null) {
+			runOnDbThread(() -> {
+				try {
+					messageTracker.storeMessageId(groupId, messageId);
+				} catch (DbException e) {
+					logException(LOG, WARNING, e);
+				}
+			});
+		}
+	}
+
+	protected abstract void markItemRead(I item);
+
+	/**
+	 * Returns the {@link MessageId} of the item that was at the top of the
+	 * list last time or null if there has been nothing stored, yet.
+	 */
+	@Nullable
+	MessageId getAndResetRestoredMessageId() {
+		return storedMessageId.getAndSet(null);
+	}
+
+	LiveData<LiveResult<List<I>>> getItems() {
+		return items;
+	}
+
+	LiveData<SharingInfo> getSharingInfo() {
+		return sharingController.getSharingInfo();
+	}
+
+	LiveData<Boolean> getGroupRemoved() {
+		return groupRemoved;
+	}
+
+	@Nullable
+	MessageId getAndResetScrollToItem() {
+		return scrollToItem.getAndSet(null);
+	}
+
+}

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

@@ -20,15 +20,15 @@ class ThreadScrollListener<I extends ThreadItem>
 	private static final Logger LOG =
 			getLogger(ThreadScrollListener.class.getName());
 
-	private final ThreadListController<?, I> controller;
+	private final ThreadListViewModel<I> viewModel;
 	private final UnreadMessageButton upButton, downButton;
 
 	ThreadScrollListener(ThreadItemAdapter<I> adapter,
-			ThreadListController<?, I> controller,
+			ThreadListViewModel<I> viewModel,
 			UnreadMessageButton upButton,
 			UnreadMessageButton downButton) {
 		super(adapter);
-		this.controller = controller;
+		this.viewModel = viewModel;
 		this.upButton = upButton;
 		this.downButton = downButton;
 	}
@@ -44,7 +44,7 @@ class ThreadScrollListener<I extends ThreadItem>
 	protected void onItemVisible(I item) {
 		if (!item.isRead()) {
 			item.setRead(true);
-			controller.markItemRead(item);
+			viewModel.markItemRead(item);
 		}
 	}
 

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

@@ -54,6 +54,7 @@ import androidx.fragment.app.FragmentManager;
 import androidx.lifecycle.LifecycleOwner;
 import androidx.lifecycle.LiveData;
 import androidx.lifecycle.Observer;
+import androidx.vectordrawable.graphics.drawable.VectorDrawableCompat;
 
 import static android.content.Context.KEYGUARD_SERVICE;
 import static android.content.Context.POWER_SERVICE;
@@ -88,7 +89,6 @@ import static androidx.appcompat.app.AppCompatDelegate.MODE_NIGHT_NO;
 import static androidx.appcompat.app.AppCompatDelegate.MODE_NIGHT_YES;
 import static androidx.appcompat.app.AppCompatDelegate.setDefaultNightMode;
 import static androidx.core.content.ContextCompat.getColor;
-import static androidx.core.content.ContextCompat.getDrawable;
 import static androidx.core.content.ContextCompat.getSystemService;
 import static androidx.core.graphics.drawable.DrawableCompat.setTint;
 import static androidx.core.view.ViewCompat.LAYOUT_DIRECTION_RTL;
@@ -436,7 +436,8 @@ public class UiUtils {
 	}
 
 	public static Drawable getDialogIcon(Context ctx, @DrawableRes int resId) {
-		Drawable icon = getDrawable(ctx, resId);
+		Drawable icon =
+				VectorDrawableCompat.create(ctx.getResources(), resId, null);
 		setTint(requireNonNull(icon), getColor(ctx, R.color.color_primary));
 		return icon;
 	}

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

@@ -2,7 +2,6 @@ package org.briarproject.briar.android.view;
 
 import android.content.Context;
 import android.content.res.TypedArray;
-import android.graphics.drawable.Drawable;
 import android.os.Handler;
 import android.os.Looper;
 import android.util.AttributeSet;
@@ -53,9 +52,8 @@ public class BriarRecyclerView extends FrameLayout {
 				R.styleable.BriarRecyclerView);
 		isScrollingToEnd = attributes
 				.getBoolean(R.styleable.BriarRecyclerView_scrollToEnd, true);
-		Drawable drawable = attributes
-				.getDrawable(R.styleable.BriarRecyclerView_emptyImage);
-		if (drawable != null) setEmptyImage(drawable);
+		int drawableRes = attributes.getResourceId(R.styleable.BriarRecyclerView_emptyImage, -1);
+		if (drawableRes != -1) setEmptyImage(drawableRes);
 		String emtpyText =
 				attributes.getString(R.styleable.BriarRecyclerView_emptyText);
 		if (emtpyText != null) setEmptyText(emtpyText);
@@ -89,6 +87,26 @@ public class BriarRecyclerView extends FrameLayout {
 		}
 
 		emptyObserver = new RecyclerView.AdapterDataObserver() {
+
+			@Override
+			public void onChanged() {
+				super.onChanged();
+				showData();
+			}
+
+			@Override
+			public void onItemRangeChanged(int positionStart, int itemCount) {
+				super.onItemRangeChanged(positionStart, itemCount);
+				if (itemCount > 0) showData();
+			}
+
+			@Override
+			public void onItemRangeMoved(int fromPosition, int toPosition,
+					int itemCount) {
+				super.onItemRangeMoved(fromPosition, toPosition, itemCount);
+				if (itemCount > 0) showData();
+			}
+
 			@Override
 			public void onItemRangeInserted(int positionStart, int itemCount) {
 				super.onItemRangeInserted(positionStart, itemCount);
@@ -139,11 +157,6 @@ public class BriarRecyclerView extends FrameLayout {
 		}
 	}
 
-	public void setEmptyImage(Drawable drawable) {
-		if (recyclerView == null) initViews();
-		emptyImage.setImageDrawable(drawable);
-	}
-
 	public void setEmptyImage(@DrawableRes int res) {
 		if (recyclerView == null) initViews();
 		emptyImage.setImageResource(res);

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

@@ -4,6 +4,7 @@ import android.app.Activity;
 import android.content.ClipData;
 import android.content.Context;
 import android.content.Intent;
+import android.graphics.drawable.Drawable;
 import android.net.Uri;
 import android.os.Parcel;
 import android.os.Parcelable;
@@ -28,6 +29,7 @@ import androidx.customview.view.AbsSavedState;
 import androidx.lifecycle.LifecycleOwner;
 import androidx.lifecycle.LiveData;
 import androidx.lifecycle.Observer;
+import androidx.vectordrawable.graphics.drawable.VectorDrawableCompat;
 import uk.co.samuelwall.materialtaptargetprompt.MaterialTapTargetPrompt;
 
 import static android.os.Build.VERSION.SDK_INT;
@@ -253,12 +255,14 @@ public class TextAttachmentController extends TextSendController
 
 	public void showImageOnboarding(Activity activity) {
 		int color = resolveColorAttribute(activity, R.attr.colorControlNormal);
+		Drawable drawable = VectorDrawableCompat
+				.create(activity.getResources(), R.drawable.ic_image, null);
 		new MaterialTapTargetPrompt.Builder(activity,
 				R.style.OnboardingDialogTheme).setTarget(sendButton)
 				.setPrimaryText(R.string.dialog_title_image_support)
 				.setSecondaryText(R.string.dialog_message_image_support)
 				.setBackgroundColour(getColor(activity, R.color.briar_primary))
-				.setIcon(R.drawable.ic_image)
+				.setIconDrawable(drawable)
 				.setIconDrawableColourFilter(color)
 				.show();
 	}

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

@@ -8,7 +8,6 @@ import org.briarproject.briar.R;
 
 import androidx.annotation.UiThread;
 import androidx.appcompat.widget.AppCompatImageView;
-import androidx.core.content.ContextCompat;
 
 @UiThread
 public class TrustIndicatorView extends AppCompatImageView {
@@ -44,7 +43,7 @@ public class TrustIndicatorView extends AppCompatImageView {
 			default:
 				res = R.drawable.trust_indicator_unknown;
 		}
-		setImageDrawable(ContextCompat.getDrawable(getContext(), res));
+		setImageResource(res);
 		setVisibility(VISIBLE);
 
 		invalidate();

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

@@ -5,6 +5,7 @@ import android.app.Application;
 import org.briarproject.bramble.api.db.DatabaseExecutor;
 import org.briarproject.bramble.api.db.DbCallable;
 import org.briarproject.bramble.api.db.DbException;
+import org.briarproject.bramble.api.db.DbRunnable;
 import org.briarproject.bramble.api.db.Transaction;
 import org.briarproject.bramble.api.db.TransactionManager;
 import org.briarproject.bramble.api.lifecycle.LifecycleManager;
@@ -23,6 +24,7 @@ import androidx.annotation.NonNull;
 import androidx.annotation.Nullable;
 import androidx.annotation.UiThread;
 import androidx.arch.core.util.Function;
+import androidx.core.util.Consumer;
 import androidx.lifecycle.AndroidViewModel;
 import androidx.lifecycle.LiveData;
 import androidx.recyclerview.widget.RecyclerView;
@@ -57,8 +59,8 @@ public abstract class DbViewModel extends AndroidViewModel {
 	}
 
 	/**
-	 * Runs the given task on the {@link DatabaseExecutor}
-	 * and waits for the DB to open.
+	 * Waits for the DB to open and runs the given task on the
+	 * {@link DatabaseExecutor}.
 	 * <p>
 	 * If you need a list of items to be displayed in a
 	 * {@link RecyclerView.Adapter},
@@ -76,6 +78,29 @@ public abstract class DbViewModel extends AndroidViewModel {
 		});
 	}
 
+	/**
+	 * Waits for the DB to open and runs the given task on the
+	 * {@link DatabaseExecutor}.
+	 * <p>
+	 * If you need a list of items to be displayed in a
+	 * {@link RecyclerView.Adapter},
+	 * use {@link #loadList(DbCallable, UiConsumer)} instead.
+	 */
+	protected void runOnDbThread(boolean readOnly,
+			DbRunnable<Exception> task, Consumer<Exception> err) {
+		dbExecutor.execute(() -> {
+			try {
+				lifecycleManager.waitForDatabase();
+				db.transaction(readOnly, task);
+			} catch (InterruptedException e) {
+				LOG.warning("Interrupted while waiting for database");
+				Thread.currentThread().interrupt();
+			} catch (Exception e) {
+				err.accept(e);
+			}
+		});
+	}
+
 	/**
 	 * Loads a list of items on the {@link DatabaseExecutor} within a single
 	 * {@link Transaction} and publishes it as a {@link LiveResult}

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

@@ -39,6 +39,17 @@ public class LiveEvent<T> extends LiveData<LiveEvent.ConsumableEvent<T>> {
 		super.observeForever(observer);
 	}
 
+	/**
+	 * Returns the last value of the event (even if already consumed)
+	 * or null if there hasn't been any value so far.
+	 */
+	@Nullable
+	public T getLastValue() {
+		ConsumableEvent<T> event = getValue();
+		if (event == null) return null;
+		return event.content;
+	}
+
 	static class ConsumableEvent<T> {
 
 		private final T content;

briar-android/src/main/res/drawable-anydpi-v24/notification_blog.xml

@@ -1,10 +1,10 @@
 <?xml version="1.0" encoding="utf-8"?>
 <vector xmlns:android="http://schemas.android.com/apk/res/android"
-        android:width="24dp"
-        android:height="24dp"
-        android:viewportHeight="24.0"
-        android:viewportWidth="24.0">
+	android:width="24dp"
+	android:height="24dp"
+	android:viewportWidth="24.0"
+	android:viewportHeight="24.0">
 	<path
 		android:fillColor="#FFFFFFFF"
-		android:pathData="M13,12h7v1.5h-7zM13,9.5h7L20,11h-7zM13,14.5h7L20,16h-7zM21,4L3,4c-1.1,0 -2,0.9 -2,2v13c0,1.1 0.9,2 2,2h18c1.1,0 2,-0.9 2,-2L23,6c0,-1.1 -0.9,-2 -2,-2zM21,19h-9L12,6h9v13z"/>
+		android:pathData="M13,12h7v1.5h-7zM13,9.5h7L20,11h-7zM13,14.5h7L20,16h-7zM21,4L3,4c-1.1,0 -2,0.9 -2,2v13c0,1.1 0.9,2 2,2h18c1.1,0 2,-0.9 2,-2L23,6c0,-1.1 -0.9,-2 -2,-2zM21,19h-9L12,6h9v13z" />
 </vector>

briar-android/src/main/res/drawable-anydpi-v24/notification_contact_added.xml

@@ -1,10 +1,10 @@
 <?xml version="1.0" encoding="utf-8"?>
 <vector xmlns:android="http://schemas.android.com/apk/res/android"
-        android:width="24dp"
-        android:height="24dp"
-        android:viewportHeight="24.0"
-        android:viewportWidth="24.0">
+	android:width="24dp"
+	android:height="24dp"
+	android:viewportWidth="24.0"
+	android:viewportHeight="24.0">
 	<path
 		android:fillColor="#FFFFFFFF"
-		android:pathData="M20,0L4,0v2h16L20,0zM4,24h16v-2L4,22v2zM20,4L4,4c-1.1,0 -2,0.9 -2,2v12c0,1.1 0.9,2 2,2h16c1.1,0 2,-0.9 2,-2L22,6c0,-1.1 -0.9,-2 -2,-2zM12,6.75c1.24,0 2.25,1.01 2.25,2.25s-1.01,2.25 -2.25,2.25S9.75,10.24 9.75,9 10.76,6.75 12,6.75zM17,17L7,17v-1.5c0,-1.67 3.33,-2.5 5,-2.5s5,0.83 5,2.5L17,17z"/>
+		android:pathData="M20,0L4,0v2h16L20,0zM4,24h16v-2L4,22v2zM20,4L4,4c-1.1,0 -2,0.9 -2,2v12c0,1.1 0.9,2 2,2h16c1.1,0 2,-0.9 2,-2L22,6c0,-1.1 -0.9,-2 -2,-2zM12,6.75c1.24,0 2.25,1.01 2.25,2.25s-1.01,2.25 -2.25,2.25S9.75,10.24 9.75,9 10.76,6.75 12,6.75zM17,17L7,17v-1.5c0,-1.67 3.33,-2.5 5,-2.5s5,0.83 5,2.5L17,17z" />
 </vector>

briar-android/src/main/res/drawable-anydpi-v24/notification_lock.xml

@@ -0,0 +1,15 @@
+<vector xmlns:android="http://schemas.android.com/apk/res/android"
+    android:width="24dp"
+    android:height="24dp"
+    android:viewportWidth="24"
+    android:viewportHeight="24"
+    android:tint="#FFFFFF">
+  <group android:scaleX="0.92"
+      android:scaleY="0.92"
+      android:translateX="0.96"
+      android:translateY="0.96">
+    <path
+        android:fillColor="@android:color/white"
+        android:pathData="M18,8h-1L17,6c0,-2.76 -2.24,-5 -5,-5S7,3.24 7,6v2L6,8c-1.1,0 -2,0.9 -2,2v10c0,1.1 0.9,2 2,2h12c1.1,0 2,-0.9 2,-2L20,10c0,-1.1 -0.9,-2 -2,-2zM12,17c-1.1,0 -2,-0.9 -2,-2s0.9,-2 2,-2 2,0.9 2,2 -0.9,2 -2,2zM15.1,8L8.9,8L8.9,6c0,-1.71 1.39,-3.1 3.1,-3.1 1.71,0 3.1,1.39 3.1,3.1v2z"/>
+  </group>
+</vector>

briar-android/src/main/res/drawable-anydpi-v24/notification_private_group.xml

@@ -1,10 +1,10 @@
 <?xml version="1.0" encoding="utf-8"?>
 <vector xmlns:android="http://schemas.android.com/apk/res/android"
-        android:width="24dp"
-        android:height="24dp"
-        android:viewportHeight="24.0"
-        android:viewportWidth="24.0">
+	android:width="24dp"
+	android:height="24dp"
+	android:viewportWidth="24.0"
+	android:viewportHeight="24.0">
 	<path
 		android:fillColor="#FFFFFFFF"
-		android:pathData="M16,11c1.66,0 2.99,-1.34 2.99,-3S17.66,5 16,5c-1.66,0 -3,1.34 -3,3s1.34,3 3,3zM8,11c1.66,0 2.99,-1.34 2.99,-3S9.66,5 8,5C6.34,5 5,6.34 5,8s1.34,3 3,3zM8,13c-2.33,0 -7,1.17 -7,3.5L1,19h14v-2.5c0,-2.33 -4.67,-3.5 -7,-3.5zM16,13c-0.29,0 -0.62,0.02 -0.97,0.05 1.16,0.84 1.97,1.97 1.97,3.45L17,19h6v-2.5c0,-2.33 -4.67,-3.5 -7,-3.5z"/>
+		android:pathData="M16,11c1.66,0 2.99,-1.34 2.99,-3S17.66,5 16,5c-1.66,0 -3,1.34 -3,3s1.34,3 3,3zM8,11c1.66,0 2.99,-1.34 2.99,-3S9.66,5 8,5C6.34,5 5,6.34 5,8s1.34,3 3,3zM8,13c-2.33,0 -7,1.17 -7,3.5L1,19h14v-2.5c0,-2.33 -4.67,-3.5 -7,-3.5zM16,13c-0.29,0 -0.62,0.02 -0.97,0.05 1.16,0.84 1.97,1.97 1.97,3.45L17,19h6v-2.5c0,-2.33 -4.67,-3.5 -7,-3.5z" />
 </vector>

briar-android/src/main/res/drawable-anydpi-v24/notification_private_message.xml

@@ -1,10 +1,10 @@
 <?xml version="1.0" encoding="utf-8"?>
 <vector xmlns:android="http://schemas.android.com/apk/res/android"
-        android:width="24dp"
-        android:height="24dp"
-        android:viewportHeight="24.0"
-        android:viewportWidth="24.0">
+	android:width="24dp"
+	android:height="24dp"
+	android:viewportWidth="24.0"
+	android:viewportHeight="24.0">
 	<path
 		android:fillColor="#FFFFFFFF"
-		android:pathData="M20,2L4,2c-1.1,0 -1.99,0.9 -1.99,2L2,22l4,-4h14c1.1,0 2,-0.9 2,-2L22,4c0,-1.1 -0.9,-2 -2,-2zM18,14L6,14v-2h12v2zM18,11L6,11L6,9h12v2zM18,8L6,8L6,6h12v2z"/>
+		android:pathData="M20,2L4,2c-1.1,0 -1.99,0.9 -1.99,2L2,22l4,-4h14c1.1,0 2,-0.9 2,-2L22,4c0,-1.1 -0.9,-2 -2,-2zM18,14L6,14v-2h12v2zM18,11L6,11L6,9h12v2zM18,8L6,8L6,6h12v2z" />
 </vector>

briar-android/src/main/res/drawable-anydpi-v24/notification_signout.xml

@@ -0,0 +1,15 @@
+<vector xmlns:android="http://schemas.android.com/apk/res/android"
+    android:width="24dp"
+    android:height="24dp"
+    android:viewportWidth="24"
+    android:viewportHeight="24"
+    android:tint="#FFFFFF">
+  <group android:scaleX="0.92"
+      android:scaleY="0.92"
+      android:translateX="0.96"
+      android:translateY="0.96">
+    <path
+        android:fillColor="#FF000000"
+        android:pathData="M16,17V14H9V10H16V7L21,12L16,17M14,2A2,2 0,0 1,16 4V6H14V4H5V20H14V18H16V20A2,2 0,0 1,14 22H5A2,2 0,0 1,3 20V4A2,2 0,0 1,5 2H14Z"/>
+  </group>
+</vector>