媒体没有在app中播放

Question

Toast弹出，所以我知道这个方法被称为声音不起作用。我的手机音量也开启了。任何想法为什么我没有声音？

public void play(View view)
{
    Toast.makeText(this, "Yo", Toast.LENGTH_SHORT).show();
    int resourceId = R.raw.meow;
    MediaPlayer mediaPlayer = MediaPlayer.create( this , resourceId );
    mediaPlayer.setOnCompletionListener( new OnCompletionListener()
    {
        @Override
        public void onCompletion( MediaPlayer mp )
        {
            mp.release();
        }
    } );
    mediaPlayer.start();
}