Android foreground service notification not showing

Question

I am trying to start a foreground service. I get notified that the service does start but the notification always gets suppressed. I double checked that the app is allowed to show notifications in the app info on my device. Here is my code:

private void showNotification() {
    Intent notificationIntent = new Intent(this, MainActivity.class);
    notificationIntent.setAction(Constants.ACTION.MAIN_ACTION);
    notificationIntent.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK
            | Intent.FLAG_ACTIVITY_CLEAR_TASK);
    PendingIntent pendingIntent = PendingIntent.getActivity(this, 0,
            notificationIntent, 0);

    Bitmap icon = BitmapFactory.decodeResource(getResources(),
            R.mipmap.ic_launcher);

    Notification notification = new NotificationCompat.Builder(getApplicationContext())
            .setContentTitle("Revel Is Running")
            .setTicker("Revel Is Running")
            .setContentText("Click to stop")
            .setSmallIcon(R.mipmap.ic_launcher)
            //.setLargeIcon(Bitmap.createScaledBitmap(icon, 128, 128, false))
            .setContentIntent(pendingIntent)
            .setOngoing(true).build();
    startForeground(Constants.FOREGROUND_SERVICE,
            notification);
    Log.e(TAG,"notification shown");

}

Here is the only error I see in relation: 06-20 12:26:43.635 895-930/? E/NotificationService: Suppressing notification from the package by user request.

Answer 1

It's because of Android O bg services restrictions.

So now you need to call startForeground() only for services that were started with startForegroundService() and call it in first 5 seconds after service has been started.

Here is the guide - https://developer.android.com/about/versions/oreo/background#services

Like this:

//Start service:
if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) {
  startForegroundService(new Intent(this, YourService.class));
} else {
  startService(new Intent(this, YourService.class));
}

Then create and show notification (with channel as supposed earlier):

private void createAndShowForegroundNotification(Service yourService, int notificationId) {

    final NotificationCompat.Builder builder = getNotificationBuilder(yourService,
         "com.example.your_app.notification.CHANNEL_ID_FOREGROUND", // Channel id
    NotificationManagerCompat.IMPORTANCE_LOW); //Low importance prevent visual appearance for this notification channel on top 
    builder.setOngoing(true)
    .setSmallIcon(R.drawable.small_icon)
    .setContentTitle(yourService.getString(R.string.title))
    .setContentText(yourService.getString(R.string.content));

    Notification notification = builder.build();

    yourService.startForeground(notificationId, notification);

    if (notificationId != lastShownNotificationId) {
          // Cancel previous notification
          final NotificationManager nm = (NotificationManager) yourService.getSystemService(Activity.NOTIFICATION_SERVICE);
          nm.cancel(lastShownNotificationId);
    }
    lastShownNotificationId = notificationId;
}

public static NotificationCompat.Builder getNotificationBuilder(Context context, String channelId, int importance) {
    NotificationCompat.Builder builder;
    if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) {
        prepareChannel(context, channelId, importance);
        builder = new NotificationCompat.Builder(context, channelId);
    } else {
        builder = new NotificationCompat.Builder(context);
    }
    return builder;
}

@TargetApi(26)
private static void prepareChannel(Context context, String id, int importance) {
    final String appName = context.getString(R.string.app_name);
    String description = context.getString(R.string.notifications_channel_description);
    final NotificationManager nm = (NotificationManager) context.getSystemService(Activity.NOTIFICATION_SERVICE);

    if(nm != null) {
        NotificationChannel nChannel = nm.getNotificationChannel(id);

        if (nChannel == null) {
            nChannel = new NotificationChannel(id, appName, importance);
            nChannel.setDescription(description);
            nm.createNotificationChannel(nChannel);
        }
    }
}

Remember that your foreground notification will have the same state as your other notifications even if you'll use different channel ids, so it might be hidden as a group with others. Use different groups to avoid it.