Show number of connected devices in notification.

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

@@ -116,4 +116,10 @@
     <!-- Notification text for incoming message -->
     <string name="notification_message">New message!</string>
 
+    <!-- Info text for persistent notification -->
+    <plurals name="notification_connections">
+        <item quantity="one">Connected to %1$s device</item>
+        <item quantity="other">Connected to %1$s devices</item>
+    </plurals>
+
 </resources>

android/src/main/scala/com/nutomic/ensichat/service/CallbackHandler.scala

@@ -18,22 +18,24 @@ object CallbackHandler {
 /**
  * Receives events from [[ConnectionHandler]] and sends them as local broadcasts.
  */
-class CallbackHandler(context: Context, notificationHandler: NotificationHandler)
+class CallbackHandler(chatService: ChatService, notificationHandler: NotificationHandler)
   extends CallbackInterface {
 
   def onMessageReceived(msg: Message): Unit = {
     notificationHandler.onMessageReceived(msg)
     val i = new Intent(ActionMessageReceived)
     i.putExtra(ExtraMessage, msg)
-    LocalBroadcastManager.getInstance(context)
+    LocalBroadcastManager.getInstance(chatService)
       .sendBroadcast(i)
 
   }
 
   def onConnectionsChanged(): Unit = {
     val i = new Intent(ActionConnectionsChanged)
-    LocalBroadcastManager.getInstance(context)
+    LocalBroadcastManager.getInstance(chatService)
       .sendBroadcast(i)
+    notificationHandler
+      .updatePersistentNotification(chatService.getConnectionHandler.connections().size)
   }
 
 }

android/src/main/scala/com/nutomic/ensichat/service/ChatService.scala

@@ -52,7 +52,7 @@ class ChatService extends Service {
    */
   override def onCreate(): Unit = {
     super.onCreate()
-    notificationHandler.showPersistentNotification()
+    notificationHandler.updatePersistentNotification(getConnectionHandler.connections().size)
     if (Option(BluetoothAdapter.getDefaultAdapter).isDefined) {
       connectionHandler.addTransmissionInterface(new BluetoothInterface(this, new Handler(),
         connectionHandler))
@@ -62,7 +62,7 @@ class ChatService extends Service {
   }
 
   override def onDestroy(): Unit = {
-    notificationHandler.cancelPersistentNotification()
+    notificationHandler.stopPersistentNotification()
     connectionHandler.stop()
     unregisterReceiver(networkReceiver)
   }

android/src/main/scala/com/nutomic/ensichat/service/NotificationHandler.scala

@@ -27,11 +27,20 @@ class NotificationHandler(context: Context) {
   private lazy val notificationManager = context.getSystemService(Context.NOTIFICATION_SERVICE)
     .asInstanceOf[NotificationManager]
 
-  def showPersistentNotification(): Unit = {
+  private var persistentNotificationShutdown = false
+
+  def updatePersistentNotification(connections: Int): Unit = {
+    if (persistentNotificationShutdown)
+      return
+
     val intent = PendingIntent.getActivity(context, 0, new Intent(context, classOf[MainActivity]), 0)
+    val info = context.getResources
+      .getQuantityString(R.plurals.notification_connections, connections, connections.toString)
+
     val notification = new NotificationCompat.Builder(context)
       .setSmallIcon(R.drawable.ic_launcher)
       .setContentTitle(context.getString(R.string.app_name))
+      .setContentText(info)
       .setContentIntent(intent)
       .setOngoing(true)
       .setPriority(Notification.PRIORITY_MIN)
@@ -39,7 +48,15 @@ class NotificationHandler(context: Context) {
     notificationManager.notify(NotificationIdRunning, notification)
   }
 
-  def cancelPersistentNotification() =  notificationManager.cancel(NotificationIdRunning)
+  /**
+   * Cancels the persistent notification.
+   *
+   * After calling this method, [[updatePersistentNotification()]] will have no effect.
+   */
+  def stopPersistentNotification() = {
+    persistentNotificationShutdown = true
+    notificationManager.cancel(NotificationIdRunning)
+  }
 
   def onMessageReceived(msg: Message): Unit = msg.body match {
     case text: Text =>