how to increase and decrease the volume programmatically in android

Question

I created the music player app and i want to set the volume up/down programmatically .

I want to implement two another

Answer 1

if your type is AudioManager.STREAM_MUSIC： use this code ，follow phone volume button

@Override
public boolean onKeyDown(int keyCode, KeyEvent event) {
    switch (keyCode) {
    case KeyEvent.KEYCODE_VOLUME_UP:
        audio.adjustStreamVolume(
            AudioManager.STREAM_MUSIC,
            AudioManager.ADJUST_RAISE,
            AudioManager.FLAG_PLAY_SOUND | AudioManager.FLAG_SHOW_UI);
        return true;
    case KeyEvent.KEYCODE_VOLUME_DOWN:
        audio.adjustStreamVolume(
            AudioManager.STREAM_MUSIC,
            AudioManager.ADJUST_LOWER,
            AudioManager.FLAG_PLAY_SOUND | AudioManager.FLAG_SHOW_UI);
        return true;
    default:
        break;
    }
    return super.onKeyDown(keyCode, event);
}