setStreamMute
did not work for me to mute the alarm, but using setStreamVolume
for STREAM_ALARM
setting volume to zero did. It is necessary to restore the alarm volume afterwards.
For example like this:
AudioManager manager = (AudioManager)getSystemService(Context.AUDIO_SERVICE);
manager.setStreamVolume(AudioManager.STREAM_ALARM, 0, AudioManager.FLAG_REMOVE_SOUND_AND_VIBRATE);