How to make my Android app play sound even in Do Not Disturb Mode

You can enable ringer mode in the following way:

1. AudioManager mAudioManager = (AudioManager)getSystemService(Context.AUDIO_SERVICE); 
2. mAudioManager.setRingerMode(AudioManager.RINGER_MODE_NORMAL); /* set ringer mode */ 

or increase up the volume of media player and play the desired tone:

1. MediaPlayer player = MediaPlayer.create(context, R.raw.xyz); /* set tone or use setDataSource method */ 
2. final AudioManager mAudioManager = (AudioManager)getSystemService(Context.AUDIO_SERVICE); 
3. final int originalVolume = mAudioManager.getStreamVolume(AudioManager.STREAM_MUSIC); 
4. mAudioManager.setStreamVolume(AudioManager.STREAM_MUSIC, mAudioManager.getStreamMaxVolume(AudioManager.STREAM_MUSIC), 0); 
5. player.setVolume(100, 100); 
6. player.prepare(); 
7. player.start(); 
8.  
9. player.setOnCompletionListener(new OnCompletionListener(){ 
10. @Override 
11. public void onCompletion(MediaPlayer player){ 
12. mAudioManager.setStreamVolume(AudioManager.STREAM_MUSIC, originalVolume, 0); 
13. player.release(); 
14. player.stop(); } 
15. });