java - Android MediaPlayer.OnBufferingUpdateListener - 缓冲内容的百分比为负

Question

我有一个使用 MediaPlayer 来流式传输网络电台的服务:

public class MediaPlayerService extends Service implements 
    MediaPlayer.OnPreparedListener,
    MediaPlayer.OnBufferingUpdateListener {

    private MediaPlayer mMediaPlayer;
    private WifiLock mWifiLock;

    public int onStartCommand(Intent intent, int flags, int startId) {
        mMediaPlayer = new MediaPlayer();

        mMediaPlayer.setOnBufferingUpdateListener(this);
        mMediaPlayer.setOnPreparedListener(this);

        mMediaPlayer.setAudioStreamType(AudioManager.STREAM_MUSIC);
        mMediaPlayer.setDataSource(MY_URL);

        // Acquire CPU lock and wi-fi lock

        mMediaPlayer.setWakeMode(getApplicationContext(), PowerManager.PARTIAL_WAKE_LOCK);
        mWifiLock = ((WifiManager) getSystemService(Context.WIFI_SERVICE))
             .createWifiLock(WifiManager.WIFI_MODE_FULL, "Media Player Wi-Fi Lock");
        mWifiLock.acquire();

        mMediaPlayer.prepareAsync();

        return START_STICKY;
    }

    @Override
    public void onPrepared(MediaPlayer mediaPlayer) {
        mMediaPlayer.start();
    }

    @Override
    public void onBufferingUpdate(MediaPlayer mp, int percent) {
        Log.d("Buffered " + percent);
    }
}

除了 onBufferingUpdate(...) 方法外，一切都很好。它在日志中打印:

Buffered -819200000 
Buffered -819200000 
Buffered -1228800000 
Buffered -1228800000 
Buffered -1228800000 
Buffered -1228800000 
Buffered -1638400000 
Buffered -1638400000 
Buffered -1638400000 
Buffered -1638400000 
Buffered -2048000000 
Buffered -2048000000 
Buffered -2048000000 
Buffered -2048000000 
Buffered -2147483648 (repeated further on) 

Note: -2147483648 is Integer MIN_VALUE

虽然 percent 应该是:

The percentage (0-100) of the content that has been buffered or played thus far

问题:

1. 为什么在 onBufferingUpdate() percent 参数中传递了不正确的值？
2. 如何解决？
3. 是否有任何其他方法可以获取已缓冲的数据量？我的目标是显示一个进度条，让用户了解何时会缓冲足够的数据并开始播放广播。

谢谢!

Answer 1

我不确定为什么会这样，我遇到了同样的问题，但这段代码可能对你有帮助:

@Override
            public void onBufferingUpdate(MediaPlayer mp, int percent) {
                // TODO Auto-generated method stub

                if (percent < 0 || percent > 100) {
                    //System.out.println("Doing math: (" + (Math.abs(percent)-1)*100.0 + " / " +Integer.MAX_VALUE+ ")" );
                    percent = (int) Math.round((((Math.abs(percent)-1)*100.0/Integer.MAX_VALUE)));

                }
                progressBar.setProgress(percent);
                Log.i("Buffering! " , " " +percent );
                System.out.println("Buffering: " +percent);

            }