Android 9 Development Cookbook - Third Edition

Playing music in the background

Our example is meant to play audio when the application is in the foreground, and will release the MediaPlayer resources in the onStop() callback. What if you are creating a music player and want to play music in the background, even when the user is using another application? In that scenario, you'll want to use MediaPlayer in a service, instead of an activity. You'll use the MediaPlayer library the same way; you'll just need to pass information (such as sound selection) from the UI to your service.

Note that since a service runs in the same UI thread as the activities, you still do not want to perform potentially blocking operations in a service. MediaPlayer does handle background threads to prevent blocking ...