Set 音量 + Get 音量

AudioManager mAudioManager = (AudioManager) getSystemService(Context.AUDIO_SERVICE);

mAudioManager.setStreamVolume(AudioManager.STREAM_MUSIC, 10, AudioManager.FLAG_SHOW_UI);

//音乐音量

int max = mAudioManager.getStreamMaxVolume( AudioManager.STREAM_MUSIC );
int current = mAudioManager.getStreamVolume( AudioManager.STREAM_MUSIC );