如何将意图发送到正在运行的服务或后台活动？

Question

I am deveoping a music player in Android right now and am currently stuck with the Notification. I added three Actions to the Notification for Previous, Play/Pause and Next. Each action needs a PendingIntent to be execute if these buttons are clicked.

My app is currently build that there is a MainActivity and a Service, which to playback the loaded audio files. The Main activity communicates through a reference to the service to do actions like next song and such.

What I want to achieve with the actions on the Notifications is that an intent is send to either the service itself, but without starting it or to the MainActivity but without bringing it back to the foreground if its currently in the background. So that either the service can control that action itself or let the MainActivity call the appropriate method.

After some research I found some people doing that with Broadcast Receivers, but as far as I understand it Broadcasts are send to any suitable application, which i definietly dont want. I also am not able to find some piece of documentation or similar that points toward a solution.

What is the best way to do this?

Any help is appreciated!

Answer 1

... but as far as I understand it Broadcasts are send to any suitable application

If you use an explicit Intent for your BroadcastReceiver like they do in the guide on creating a Notification then you can be sure that no other component will receive the broadcast (code snippet copied from there):

Intent snoozeIntent = new Intent(this, MyBroadcastReceiver.class);
snoozeIntent.setAction(ACTION_SNOOZE);
snoozeIntent.putExtra(EXTRA_NOTIFICATION_ID, 0);
PendingIntent snoozePendingIntent =
        PendingIntent.getBroadcast(this, 0, snoozeIntent, 0);

So it looks like this is the way to go: have your BroadcastReceiver instance decide which component of your app should take control.