How to stop other apps playing music from my current activity?

问题

In my app I am trying to make a button which when clicked stops all other apps that are playing music. What I want is similar to that if I am playing music through one music player and if I try playing some other music through a second music player, the current music player stops and then the second one starts. How do we stop other apps playing music from current activity/app?

回答1:

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

// Request audio focus for playback
int result = am.requestAudioFocus(focusChangeListener,
// Use the music stream.
AudioManager.STREAM_MUSIC,
// Request permanent focus.
AudioManager.AUDIOFOCUS_GAIN);


if (result == AudioManager.AUDIOFOCUS_REQUEST_GRANTED) {
// other app had stopped playing song now , so u can do u stuff now .
}

Audio focus is assigned in turn to each application that requests it. This means that if another application requests audio focus, your application will lose it. You will be notifi ed of the loss of audio focus through the onAudioFocusChange handler of the Audio Focus Change Listener you registered when requesting the audio focus

      private OnAudioFocusChangeListener focusChangeListener =
          new OnAudioFocusChangeListener() {
                  public void onAudioFocusChange(int focusChange) {
                             AudioManager am =(AudioManager)getSystemService(Context.AUDIO_SERVICE);
                    switch (focusChange) {

                           case (AudioManager.AUDIOFOCUS_LOSS_TRANSIENT_CAN_DUCK) :
                           // Lower the volume while ducking.
                           mediaPlayer.setVolume(0.2f, 0.2f);
                           break;
                           case (AudioManager.AUDIOFOCUS_LOSS_TRANSIENT) :
                           pause();
                           break;

                           case (AudioManager.AUDIOFOCUS_LOSS) :
                           stop();
                           ComponentName component =new ComponentName(AudioPlayerActivity.this,MediaControlReceiver.class);
                           am.unregisterMediaButtonEventReceiver(component);
                           break;

                           case (AudioManager.AUDIOFOCUS_GAIN) :
                           // Return the volume to normal and resume if paused.
                           mediaPlayer.setVolume(1f, 1f);
                           mediaPlayer.start();
                           break;
                           default: break;
}
}
};

回答2:

You need to use the media players audio focus implementations found in the docs here:

http://developer.android.com/guide/topics/media/mediaplayer.html#audiofocus

来源：https://stackoverflow.com/questions/15390126/how-to-stop-other-apps-playing-music-from-my-current-activity