Merge branch '646-shared-with-subtitle' into 'master'

Add blog sharing information to toolbar subtitle

This MR introduces a new `SharingController` which is supposed to be used in activities that show blogs, groups and forums. Feedback on this approach is welcome before this is used to add "Shared with" support to other parts of the UI.

The toolbar subtitle shows information about how many contacts the current shareable is shared with and how many of those are online.

So far this is implemented for blogs:

![device-2016-12-05-180207](/uploads/13afb4c7c5d10ad29c414865ee02670d/device-2016-12-05-180207.png)

One part of #646

See merge request !447

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

@@ -2,38 +2,60 @@ package org.briarproject.briar.android.blog;
 
 import android.content.Intent;
 import android.os.Bundle;
+import android.support.annotation.Nullable;
+import android.view.View;
 
+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.activity.ActivityComponent;
 import org.briarproject.briar.android.activity.BriarActivity;
 import org.briarproject.briar.android.blog.BlogPostAdapter.OnBlogPostClickListener;
 import org.briarproject.briar.android.fragment.BaseFragment.BaseFragmentListener;
+import org.briarproject.briar.android.sharing.BlogSharingStatusActivity;
 
 import javax.inject.Inject;
 
+@MethodsNotNullByDefault
+@ParametersNotNullByDefault
 public class BlogActivity extends BriarActivity implements
 		OnBlogPostClickListener, BaseFragmentListener {
 
-	static final int REQUEST_WRITE_POST = 1;
-	static final int REQUEST_SHARE = 2;
+	static final int REQUEST_WRITE_POST = 2;
+	static final int REQUEST_SHARE = 3;
 
 	@Inject
 	BlogController blogController;
 
 	@Override
-	public void onCreate(Bundle state) {
+	public void onCreate(@Nullable Bundle state) {
 		super.onCreate(state);
 
 		// GroupId from Intent
 		Intent i = getIntent();
 		byte[] b = i.getByteArrayExtra(GROUP_ID);
 		if (b == null) throw new IllegalStateException("No group ID in intent");
-		GroupId groupId = new GroupId(b);
+		final GroupId groupId = new GroupId(b);
 		blogController.setGroupId(groupId);
 
 		setContentView(R.layout.activity_fragment_container);
 
+		// Open Sharing Status on ActionBar click
+		View actionBar = findViewById(R.id.action_bar);
+		if (actionBar != null) {
+			actionBar.setOnClickListener(
+					new View.OnClickListener() {
+						@Override
+						public void onClick(View v) {
+							Intent i = new Intent(BlogActivity.this,
+									BlogSharingStatusActivity.class);
+							i.putExtra(GROUP_ID, groupId.getBytes());
+							startActivity(i);
+						}
+					});
+		}
+
 		if (state == null) {
 			BlogFragment f = BlogFragment.newInstance(groupId);
 			getSupportFragmentManager().beginTransaction()
@@ -59,4 +81,5 @@ public class BlogActivity extends BriarActivity implements
 	@Override
 	public void onFragmentCreated(String tag) {
 	}
+
 }

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

@@ -1,5 +1,9 @@
 package org.briarproject.briar.android.blog;
 
+import android.support.annotation.UiThread;
+
+import org.briarproject.bramble.api.contact.Contact;
+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;
@@ -13,6 +17,8 @@ public interface BlogController extends BaseController {
 
 	void setGroupId(GroupId g);
 
+	void setBlogSharingListener(BlogSharingListener listener);
+
 	void loadBlogPosts(
 			ResultExceptionHandler<Collection<BlogPostItem>, DbException> handler);
 
@@ -23,4 +29,15 @@ public interface BlogController extends BaseController {
 
 	void deleteBlog(ResultExceptionHandler<Void, DbException> handler);
 
+	void loadSharingContacts(
+			ResultExceptionHandler<Collection<ContactId>, DbException> handler);
+
+	interface BlogSharingListener extends BlogListener {
+		@UiThread
+		void onBlogInvitationAccepted(ContactId c);
+
+		@UiThread
+		void onBlogLeft(ContactId c);
+	}
+
 }

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

@@ -2,6 +2,8 @@ package org.briarproject.briar.android.blog;
 
 import android.app.Activity;
 
+import org.briarproject.bramble.api.contact.Contact;
+import org.briarproject.bramble.api.contact.ContactId;
 import org.briarproject.bramble.api.db.DatabaseExecutor;
 import org.briarproject.bramble.api.db.DbException;
 import org.briarproject.bramble.api.event.Event;
@@ -20,8 +22,13 @@ import org.briarproject.briar.android.controller.handler.ResultExceptionHandler;
 import org.briarproject.briar.api.android.AndroidNotificationManager;
 import org.briarproject.briar.api.blog.Blog;
 import org.briarproject.briar.api.blog.BlogManager;
+import org.briarproject.briar.api.blog.BlogSharingManager;
+import org.briarproject.briar.api.blog.event.BlogInvitationResponseReceivedEvent;
 import org.briarproject.briar.api.blog.event.BlogPostAddedEvent;
+import org.briarproject.briar.api.sharing.InvitationResponse;
+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;
@@ -39,15 +46,19 @@ class BlogControllerImpl extends BaseControllerImpl
 	private static final Logger LOG =
 			Logger.getLogger(BlogControllerImpl.class.getName());
 
+	private final BlogSharingManager blogSharingManager;
 	private volatile GroupId groupId = null;
+	private volatile BlogSharingListener listener;
 
 	@Inject
 	BlogControllerImpl(@DatabaseExecutor Executor dbExecutor,
 			LifecycleManager lifecycleManager, EventBus eventBus,
 			AndroidNotificationManager notificationManager,
-			IdentityManager identityManager, BlogManager blogManager) {
+			IdentityManager identityManager, BlogManager blogManager,
+			BlogSharingManager blogSharingManager) {
 		super(dbExecutor, lifecycleManager, eventBus, notificationManager,
 				identityManager, blogManager);
+		this.blogSharingManager = blogSharingManager;
 	}
 
 	@Override
@@ -76,6 +87,12 @@ class BlogControllerImpl extends BaseControllerImpl
 		groupId = g;
 	}
 
+	@Override
+	public void setBlogSharingListener(BlogSharingListener listener) {
+		super.setBlogListener(listener);
+		this.listener = listener;
+	}
+
 	@Override
 	public void eventOccurred(Event e) {
 		if (groupId == null) throw new IllegalStateException();
@@ -85,6 +102,20 @@ class BlogControllerImpl extends BaseControllerImpl
 				LOG.info("Blog post added");
 				onBlogPostAdded(b.getHeader(), b.isLocal());
 			}
+		} else if (e instanceof BlogInvitationResponseReceivedEvent) {
+			BlogInvitationResponseReceivedEvent b =
+					(BlogInvitationResponseReceivedEvent) e;
+			InvitationResponse r = b.getResponse();
+			if (r.getGroupId().equals(groupId) && r.wasAccepted()) {
+				LOG.info("Blog invitation accepted");
+				onBlogInvitationAccepted(b.getContactId());
+			}
+		} else if (e instanceof ContactLeftShareableEvent) {
+			ContactLeftShareableEvent s = (ContactLeftShareableEvent) e;
+			if (s.getGroupId().equals(groupId)) {
+				LOG.info("Blog left by contact");
+				onBlogLeft(s.getContactId());
+			}
 		} else if (e instanceof GroupRemovedEvent) {
 			GroupRemovedEvent g = (GroupRemovedEvent) e;
 			if (g.getGroup().getId().equals(groupId)) {
@@ -94,6 +125,24 @@ class BlogControllerImpl extends BaseControllerImpl
 		}
 	}
 
+	private void onBlogInvitationAccepted(final ContactId c) {
+		listener.runOnUiThreadUnlessDestroyed(new Runnable() {
+			@Override
+			public void run() {
+				listener.onBlogInvitationAccepted(c);
+			}
+		});
+	}
+
+	private void onBlogLeft(final ContactId c) {
+		listener.runOnUiThreadUnlessDestroyed(new Runnable() {
+			@Override
+			public void run() {
+				listener.onBlogLeft(c);
+			}
+		});
+	}
+
 	@Override
 	public void loadBlogPosts(
 			final ResultExceptionHandler<Collection<BlogPostItem>, DbException> handler) {
@@ -159,4 +208,27 @@ class BlogControllerImpl extends BaseControllerImpl
 		});
 	}
 
+	@Override
+	public void loadSharingContacts(
+			final ResultExceptionHandler<Collection<ContactId>, DbException> handler) {
+		if (groupId == null) throw new IllegalStateException();
+		runOnDbThread(new Runnable() {
+			@Override
+			public void run() {
+				try {
+					Collection<Contact> contacts =
+							blogSharingManager.getSharedWith(groupId);
+					Collection<ContactId> contactIds =
+							new ArrayList<>(contacts.size());
+					for (Contact c : contacts) contactIds.add(c.getId());
+					handler.onResult(contactIds);
+				} catch (DbException e) {
+					if (LOG.isLoggable(WARNING))
+						LOG.log(WARNING, e.toString(), e);
+					handler.onException(e);
+				}
+			}
+		});
+	}
+
 }

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

@@ -7,6 +7,7 @@ import android.support.annotation.UiThread;
 import android.support.design.widget.Snackbar;
 import android.support.v4.app.ActivityOptionsCompat;
 import android.support.v4.content.ContextCompat;
+import android.support.v7.app.ActionBar;
 import android.support.v7.app.AlertDialog;
 import android.support.v7.widget.LinearLayoutManager;
 import android.view.LayoutInflater;
@@ -17,6 +18,7 @@ import android.view.View;
 import android.view.ViewGroup;
 import android.widget.Toast;
 
+import org.briarproject.bramble.api.contact.ContactId;
 import org.briarproject.bramble.api.db.DbException;
 import org.briarproject.bramble.api.identity.Author;
 import org.briarproject.bramble.api.nullsafety.MethodsNotNullByDefault;
@@ -24,8 +26,10 @@ import org.briarproject.bramble.api.nullsafety.ParametersNotNullByDefault;
 import org.briarproject.bramble.api.sync.GroupId;
 import org.briarproject.briar.R;
 import org.briarproject.briar.android.activity.ActivityComponent;
-import org.briarproject.briar.android.blog.BaseController.BlogListener;
+import org.briarproject.briar.android.activity.BriarActivity;
+import org.briarproject.briar.android.blog.BlogController.BlogSharingListener;
 import org.briarproject.briar.android.blog.BlogPostAdapter.OnBlogPostClickListener;
+import org.briarproject.briar.android.controller.SharingController;
 import org.briarproject.briar.android.controller.handler.UiResultExceptionHandler;
 import org.briarproject.briar.android.fragment.BaseFragment;
 import org.briarproject.briar.android.sharing.BlogSharingStatusActivity;
@@ -46,17 +50,20 @@ import static android.widget.Toast.LENGTH_SHORT;
 import static org.briarproject.briar.android.activity.BriarActivity.GROUP_ID;
 import static org.briarproject.briar.android.blog.BlogActivity.REQUEST_SHARE;
 import static org.briarproject.briar.android.blog.BlogActivity.REQUEST_WRITE_POST;
+import static org.briarproject.briar.android.controller.SharingController.SharingListener;
 
 @UiThread
 @MethodsNotNullByDefault
 @ParametersNotNullByDefault
-public class BlogFragment extends BaseFragment implements
-		BlogListener {
+public class BlogFragment extends BaseFragment
+		implements BlogSharingListener, SharingListener {
 
 	private final static String TAG = BlogFragment.class.getName();
 
 	@Inject
 	BlogController blogController;
+	@Inject
+	SharingController sharingController;
 
 	private GroupId groupId;
 	private BlogPostAdapter adapter;
@@ -101,13 +108,16 @@ public class BlogFragment extends BaseFragment implements
 	@Override
 	public void injectFragment(ActivityComponent component) {
 		component.inject(this);
-		blogController.setBlogListener(this);
+		blogController.setBlogSharingListener(this);
+		sharingController.setSharingListener(this);
 	}
 
 	@Override
 	public void onStart() {
 		super.onStart();
+		sharingController.onStart();
 		loadBlog();
+		loadSharedContacts();
 		loadBlogPosts(false);
 		list.startPeriodicUpdate();
 	}
@@ -115,6 +125,7 @@ public class BlogFragment extends BaseFragment implements
 	@Override
 	public void onStop() {
 		super.onStop();
+		sharingController.onStop();
 		list.stopPeriodicUpdate();
 	}
 
@@ -255,6 +266,52 @@ public class BlogFragment extends BaseFragment implements
 		getActivity().setTitle(title);
 	}
 
+	private void loadSharedContacts() {
+		blogController.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) {
+						// TODO: Decide how to handle errors in the UI
+						finish();
+					}
+				});
+	}
+
+	@Override
+	public void onBlogInvitationAccepted(ContactId c) {
+		sharingController.add(c);
+		setToolbarSubTitle(sharingController.getTotalCount(),
+				sharingController.getOnlineCount());
+	}
+
+	@Override
+	public void onBlogLeft(ContactId c) {
+		sharingController.remove(c);
+		setToolbarSubTitle(sharingController.getTotalCount(),
+				sharingController.getOnlineCount());
+	}
+
+	@Override
+	public void onSharingInfoUpdated(int total, int online) {
+		setToolbarSubTitle(total, online);
+	}
+
+	private void setToolbarSubTitle(int total, int online) {
+		ActionBar actionBar =
+				((BriarActivity) getActivity()).getSupportActionBar();
+		if (actionBar != null) {
+			actionBar.setSubtitle(
+					getString(R.string.shared_with, total, online));
+		}
+	}
+
 	private void showWriteButton() {
 		isMyBlog = true;
 		if (writeButton != null)
@@ -327,4 +384,5 @@ public class BlogFragment extends BaseFragment implements
 	public void onBlogRemoved() {
 		finish();
 	}
+
 }

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

@@ -2,6 +2,8 @@ package org.briarproject.briar.android.blog;
 
 import org.briarproject.briar.android.activity.ActivityScope;
 import org.briarproject.briar.android.activity.BaseActivity;
+import org.briarproject.briar.android.controller.SharingController;
+import org.briarproject.briar.android.controller.SharingControllerImpl;
 
 import dagger.Module;
 import dagger.Provides;
@@ -22,4 +24,12 @@ public class BlogModule {
 	FeedController provideFeedController(FeedControllerImpl feedController) {
 		return feedController;
 	}
+
+	@ActivityScope
+	@Provides
+	SharingController provideSharingController(
+			SharingControllerImpl sharingController) {
+		return sharingController;
+	}
+
 }

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

@@ -0,0 +1,71 @@
+package org.briarproject.briar.android.controller;
+
+import android.support.annotation.UiThread;
+
+import org.briarproject.bramble.api.contact.ContactId;
+import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
+import org.briarproject.bramble.api.sync.GroupId;
+import org.briarproject.briar.android.DestroyableContext;
+
+import java.util.Collection;
+
+@NotNullByDefault
+public interface SharingController {
+
+	/**
+	 * Sets the listener that is called when contacts go on or offline.
+	 */
+	@UiThread
+	void setSharingListener(SharingListener listener);
+
+	/**
+	 * Call this when your lifecycle starts,
+	 * so the listener will be called when information changes.
+	 */
+	@UiThread
+	void onStart();
+
+	/**
+	 * Call this when your lifecycle stops,
+	 * so that the controller knows it can stops listening to events.
+	 */
+	@UiThread
+	void onStop();
+
+	/**
+	 * 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 number of online contacts.
+	 */
+	@UiThread
+	int getOnlineCount();
+
+	/**
+	 * Returns the total number of contacts that have been added.
+	 */
+	@UiThread
+	int getTotalCount();
+
+	interface SharingListener extends DestroyableContext {
+		@UiThread
+		void onSharingInfoUpdated(int total, int online);
+	}
+
+}

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

@@ -0,0 +1,105 @@
+package org.briarproject.briar.android.controller;
+
+import android.support.annotation.Nullable;
+import android.support.annotation.UiThread;
+
+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.ConnectionRegistry;
+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;
+
+@NotNullByDefault
+public class SharingControllerImpl implements SharingController, EventListener {
+
+	private final EventBus eventBus;
+	private final ConnectionRegistry connectionRegistry;
+
+	@Nullable
+	private volatile SharingListener listener;
+	// only access on @UiThread
+	private final Set<ContactId> contacts = new HashSet<>();
+
+	@Inject
+	SharingControllerImpl(EventBus eventBus,
+			ConnectionRegistry connectionRegistry) {
+		this.eventBus = eventBus;
+		this.connectionRegistry = connectionRegistry;
+	}
+
+	@Override
+	public void setSharingListener(SharingListener listener) {
+		this.listener = listener;
+	}
+
+	@Override
+	public void onStart() {
+		eventBus.addListener(this);
+	}
+
+	@Override
+	public void onStop() {
+		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());
+		}
+	}
+
+	private void setConnected(final ContactId c) {
+		if (listener == null) return;
+		listener.runOnUiThreadUnlessDestroyed(new Runnable() {
+			@Override
+			public void run() {
+				if (contacts.contains(c)) {
+					int online = getOnlineCount();
+					listener.onSharingInfoUpdated(contacts.size(), online);
+				}
+			}
+		});
+	}
+
+	@Override
+	public void addAll(Collection<ContactId> c) {
+		contacts.addAll(c);
+	}
+
+	@Override
+	public void add(ContactId c) {
+		contacts.add(c);
+	}
+
+	@Override
+	public void remove(ContactId c) {
+		contacts.remove(c);
+	}
+
+	@Override
+	public int getOnlineCount() {
+		int online = 0;
+		for (ContactId c : contacts) {
+			if (connectionRegistry.isConnected(c)) online++;
+		}
+		return online;
+	}
+
+	@Override
+	public int getTotalCount() {
+		return contacts.size();
+	}
+
+}

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

@@ -259,6 +259,7 @@
 	<string name="forum_invitation_response_declined_received">%s declined the forum invitation.</string>
 
 	<string name="sharing_status">Sharing Status</string>
+	<string name="shared_with">Shared with %1$d (%2$d online)</string>
 	<plurals name="forums_shared">
 		<item quantity="one">%d forum shared by contacts</item>
 		<item quantity="other">%d forums shared by contacts</item>

briar-api/src/main/java/org/briarproject/briar/api/sharing/event/ContactLeftShareableEvent.java

@@ -0,0 +1,31 @@
+package org.briarproject.briar.api.sharing.event;
+
+
+import org.briarproject.bramble.api.contact.ContactId;
+import org.briarproject.bramble.api.event.Event;
+import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
+import org.briarproject.bramble.api.sync.GroupId;
+
+import javax.annotation.concurrent.Immutable;
+
+@Immutable
+@NotNullByDefault
+public class ContactLeftShareableEvent extends Event {
+
+	private final GroupId groupId;
+	private final ContactId contactId;
+
+	public ContactLeftShareableEvent(GroupId groupId, ContactId contactId) {
+		this.groupId = groupId;
+		this.contactId = contactId;
+	}
+
+	public GroupId getGroupId() {
+		return groupId;
+	}
+
+	public ContactId getContactId() {
+		return contactId;
+	}
+
+}

briar-core/src/main/java/org/briarproject/briar/sharing/BlogSharingManagerImpl.java

@@ -258,7 +258,7 @@ class BlogSharingManagerImpl extends
 		@Override
 		public BlogInvitation build(BlogSharerSessionState localState,
 				long time) {
-			return new BlogInvitation(localState.getGroupId(),
+			return new BlogInvitation(localState.getContactGroupId(),
 					localState.getSessionId(), localState.getBlogAuthorName(),
 					localState.getBlogPublicKey(), time,
 					localState.getMessage());
@@ -338,7 +338,7 @@ class BlogSharingManagerImpl extends
 			ContactId contactId = localState.getContactId();
 			BlogInvitationRequest request =
 					new BlogInvitationRequest(localState.getInvitationId(),
-							localState.getSessionId(), localState.getGroupId(),
+							localState.getSessionId(), localState.getContactGroupId(),
 							contactId, blog.getAuthor().getName(), msg, true,
 							time, false, false, false, false);
 			return new BlogInvitationRequestReceivedEvent(blog, contactId,
@@ -357,7 +357,8 @@ class BlogSharingManagerImpl extends
 				throw new IllegalStateException("No responseId");
 			BlogInvitationResponse response =
 					new BlogInvitationResponse(responseId,
-							localState.getSessionId(), localState.getGroupId(),
+							localState.getSessionId(),
+							localState.getShareableId(),
 							localState.getContactId(), accept, time, false,
 							false, false, false);
 			return new BlogInvitationResponseReceivedEvent(c, response);

briar-core/src/main/java/org/briarproject/briar/sharing/ForumSharingManagerImpl.java

@@ -191,7 +191,7 @@ class ForumSharingManagerImpl extends
 		@Override
 		public ForumInvitation build(ForumSharerSessionState localState,
 				long time) {
-			return new ForumInvitation(localState.getGroupId(),
+			return new ForumInvitation(localState.getContactGroupId(),
 					localState.getSessionId(), localState.getForumName(),
 					localState.getForumSalt(), time, localState.getMessage());
 		}
@@ -268,7 +268,7 @@ class ForumSharingManagerImpl extends
 			ContactId contactId = localState.getContactId();
 			ForumInvitationRequest request = new ForumInvitationRequest(
 					localState.getInvitationId(), localState.getSessionId(),
-					localState.getGroupId(), contactId, forum.getName(), msg,
+					localState.getContactGroupId(), contactId, forum.getName(), msg,
 					true, time, false, false, false, false);
 			return new ForumInvitationRequestReceivedEvent(forum, contactId,
 					request);
@@ -287,8 +287,8 @@ class ForumSharingManagerImpl extends
 				throw new IllegalStateException("No responseId");
 			ForumInvitationResponse response = new ForumInvitationResponse(
 					responseId, localState.getSessionId(),
-					localState.getGroupId(), localState.getContactId(), accept,
-					time, false, false, false, false);
+					localState.getShareableId(), localState.getContactId(),
+					accept, time, false, false, false, false);
 			return new ForumInvitationResponseReceivedEvent(name, c, response);
 		}
 	}

briar-core/src/main/java/org/briarproject/briar/sharing/InvitationReceivedEventFactory.java

@@ -3,8 +3,10 @@ package org.briarproject.briar.sharing;
 import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
 import org.briarproject.briar.api.sharing.event.InvitationRequestReceivedEvent;
 
+import javax.annotation.Nullable;
+
 @NotNullByDefault
 interface InvitationReceivedEventFactory<IS extends InviteeSessionState, IR extends InvitationRequestReceivedEvent> {
 
-	IR build(IS localState, long time, String msg);
+	IR build(IS localState, long time, @Nullable String msg);
 }

briar-core/src/main/java/org/briarproject/briar/sharing/InviteeEngine.java

@@ -77,20 +77,20 @@ class InviteeEngine<IS extends InviteeSessionState, IR extends InvitationRequest
 				if (action == InviteeSessionState.Action.LOCAL_ACCEPT) {
 					localState.setTask(TASK_ADD_SHARED_SHAREABLE);
 					msg = new SimpleMessage(SHARE_MSG_TYPE_ACCEPT,
-							localState.getGroupId(), localState.getSessionId(),
+							localState.getContactGroupId(), localState.getSessionId(),
 							clock.currentTimeMillis());
 				} else {
 					localState.setTask(
 							TASK_REMOVE_SHAREABLE_FROM_LIST_SHARED_WITH_US);
 					msg = new SimpleMessage(SHARE_MSG_TYPE_DECLINE,
-							localState.getGroupId(), localState.getSessionId(),
+							localState.getContactGroupId(), localState.getSessionId(),
 							clock.currentTimeMillis());
 				}
 				messages = Collections.singletonList(msg);
 				logLocalAction(currentState, localState, msg);
 			} else if (action == InviteeSessionState.Action.LOCAL_LEAVE) {
 				BaseMessage msg = new SimpleMessage(SHARE_MSG_TYPE_LEAVE,
-						localState.getGroupId(), localState.getSessionId(),
+						localState.getContactGroupId(), localState.getSessionId(),
 						clock.currentTimeMillis());
 				messages = Collections.singletonList(msg);
 				logLocalAction(currentState, localState, msg);
@@ -221,7 +221,7 @@ class InviteeEngine<IS extends InviteeSessionState, IR extends InvitationRequest
 		}
 		localState.setState(InviteeSessionState.State.ERROR);
 		BaseMessage msg =
-				new SimpleMessage(SHARE_MSG_TYPE_ABORT, localState.getGroupId(),
+				new SimpleMessage(SHARE_MSG_TYPE_ABORT, localState.getContactGroupId(),
 						localState.getSessionId(), clock.currentTimeMillis());
 		List<BaseMessage> messages = Collections.singletonList(msg);
 

briar-core/src/main/java/org/briarproject/briar/sharing/SharerEngine.java

@@ -86,7 +86,7 @@ class SharerEngine<I extends Invitation, SS extends SharerSessionState, IRR exte
 						.setTask(TASK_ADD_SHAREABLE_TO_LIST_TO_BE_SHARED_BY_US);
 			} else if (action == SharerSessionState.Action.LOCAL_LEAVE) {
 				BaseMessage msg = new SimpleMessage(SHARE_MSG_TYPE_LEAVE,
-						localState.getGroupId(), localState.getSessionId(),
+						localState.getContactGroupId(), localState.getSessionId(),
 						clock.currentTimeMillis());
 				messages = Collections.singletonList(msg);
 				logLocalAction(currentState, nextState, msg);
@@ -217,7 +217,7 @@ class SharerEngine<I extends Invitation, SS extends SharerSessionState, IRR exte
 
 		localState.setState(SharerSessionState.State.ERROR);
 		BaseMessage msg = new SimpleMessage(SHARE_MSG_TYPE_ABORT,
-				localState.getGroupId(), localState.getSessionId(),
+				localState.getContactGroupId(), localState.getSessionId(),
 				clock.currentTimeMillis());
 		List<BaseMessage> messages = Collections.singletonList(msg);
 

briar-core/src/main/java/org/briarproject/briar/sharing/SharingManagerImpl.java

@@ -39,6 +39,7 @@ import org.briarproject.briar.api.sharing.SharingInvitationItem;
 import org.briarproject.briar.api.sharing.SharingManager;
 import org.briarproject.briar.api.sharing.event.InvitationRequestReceivedEvent;
 import org.briarproject.briar.api.sharing.event.InvitationResponseReceivedEvent;
+import org.briarproject.briar.api.sharing.event.ContactLeftShareableEvent;
 import org.briarproject.briar.client.ConversationClientImpl;
 
 import java.io.IOException;
@@ -301,7 +302,7 @@ abstract class SharingManagerImpl<S extends Shareable, I extends Invitation, IS
 			// track message
 			// TODO handle this properly without engine hacks (#376)
 			long time = update.toSend.get(0).getTime();
-			messageTracker.trackMessage(txn, localState.getGroupId(), time,
+			messageTracker.trackMessage(txn, localState.getContactGroupId(), time,
 					true);
 
 			db.commitTransaction(txn);
@@ -365,7 +366,7 @@ abstract class SharingManagerImpl<S extends Shareable, I extends Invitation, IS
 		// track message
 		// TODO handle this properly without engine hacks (#376)
 		long time = update.toSend.get(0).getTime();
-		messageTracker.trackMessage(txn, localState.getGroupId(), time, true);
+		messageTracker.trackMessage(txn, localState.getContactGroupId(), time, true);
 	}
 
 	@Override
@@ -872,7 +873,7 @@ abstract class SharingManagerImpl<S extends Shareable, I extends Invitation, IS
 		localState.setTask(-1);
 
 		// get group ID for later
-		GroupId groupId = localState.getGroupId();
+		GroupId groupId = localState.getContactGroupId();
 		// get contact ID for later
 		ContactId contactId = localState.getContactId();
 
@@ -897,9 +898,17 @@ abstract class SharingManagerImpl<S extends Shareable, I extends Invitation, IS
 		} else if (task == TASK_UNSHARE_SHAREABLE_SHARED_BY_US) {
 			db.setGroupVisibility(txn, contactId, f.getId(), INVISIBLE);
 			removeFromList(txn, groupId, SHARED_BY_US, f);
+			// broadcast event informing UI that contact has left the group
+			ContactLeftShareableEvent
+					e = new ContactLeftShareableEvent(f.getId(), contactId);
+			txn.attach(e);
 		} else if (task == TASK_UNSHARE_SHAREABLE_SHARED_WITH_US) {
 			db.setGroupVisibility(txn, contactId, f.getId(), INVISIBLE);
 			removeFromList(txn, groupId, SHARED_WITH_US, f);
+			// broadcast event informing UI that contact has left the group
+			ContactLeftShareableEvent
+					e = new ContactLeftShareableEvent(f.getId(), contactId);
+			txn.attach(e);
 		}
 	}
 

briar-core/src/main/java/org/briarproject/briar/sharing/SharingSessionState.java

@@ -68,7 +68,7 @@ abstract class SharingSessionState {
 		BdfDictionary d = new BdfDictionary();
 		d.put(SESSION_ID, getSessionId());
 		d.put(STORAGE_ID, getStorageId());
-		d.put(GROUP_ID, getGroupId());
+		d.put(GROUP_ID, getContactGroupId());
 		d.put(CONTACT_ID, getContactId().getInt());
 		d.put(SHAREABLE_ID, getShareableId());
 
@@ -83,7 +83,7 @@ abstract class SharingSessionState {
 		return storageId;
 	}
 
-	public GroupId getGroupId() {
+	public GroupId getContactGroupId() {
 		return groupId;
 	}