Android MediaPlayer第一次以较低的音量播放声音

Question

这是我用来创建通知声音的代码。但是，首次调用该功能时，媒体播放器将以较低的音量播放声音。如果立即再次调用此函数，则它将以所需的音量（即流音量）播放。

Uri notification = RingtoneManager.getActualDefaultRingtoneUri(context, 
RingtoneManager.TYPE_NOTIFICATION);
                mMediaPlayer = new MediaPlayer();
                mMediaPlayer.setDataSource(context, notification);
                mMediaPlayer.setAudioStreamType(AudioManager.STREAM_RING);
                mMediaPlayer.setOnPreparedListener(new 
MediaPlayer.OnPreparedListener() {
                    @Override
                    public void onPrepared(MediaPlayer mp) {
                        mMediaPlayer.setVolume(1, 1);
                        if(!mMediaPlayer.isPlaying())
                           mMediaPlayer.start();
                    }
                });

                mMediaPlayer.setOnCompletionListener(new 
MediaPlayer.OnCompletionListener() {
                    @Override
                    public void onCompletion(MediaPlayer mp) {
                        mMediaPlayer.release();
                    }
                });

                mMediaPlayer.prepareAsync();

如何始终以合适的音量播放声音？