具有surfaceview的android-可视化工具

Question

我按照此链接的教程 - ＆gt; http://android-er.blogspot.com/2015/02/create-audio-visualizer-for-mediaplayer.html 通过扩展视图类来完成图形。现在我尝试用表面视图做同样的事情。这是代码：

MainActivity：

  public class MainActivity extends Activity {
  VisualizerView mVisualizerView;

  @Override
  protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    mVisualizerView= new VisualizerView(this);
    setContentView(mVisualizerView);
  }

@Override
protected void onPause(){
    super.onPause();
    if(isFinishing()){
        mVisualizerView.clean();
    }

}}

Sufaceview课程：

public class VisualizerView extends SurfaceView  implements SurfaceHolder.Callback {

 private byte[] mBytes;
 private float[] mPoints;
 private Rect mRect = new Rect();
 private Paint mForePaint = new Paint();
 SurfaceThread _thread;
 private MediaPlayer player;
    private Visualizer visualizer;  
private Context context;
 public VisualizerView(Context context) {
      super(context);
      init();
      getHolder().addCallback(this);
        _thread = new SurfaceThread(getHolder(), this);
        this.context=context;
     }

  private void init(){

      mBytes = null;
      mForePaint.setStrokeWidth(1f);
      mForePaint.setAntiAlias(true);
      mForePaint.setColor(Color.rgb(0,0, 255));
  }
  public void updateVisualizer(byte[] bytes) {
      mBytes = bytes;
    //  invalidate();
     }

  private void initAudio(){

     player= MediaPlayer.create(context, R.raw.duck);

     setupVisualizerFxAndUI();
     visualizer.setEnabled(true);
     player.setOnCompletionListener(new MediaPlayer.OnCompletionListener(){
         public void onCompletion(MediaPlayer mediaPlayer){
           visualizer.setEnabled(false);
         }
        }

         );
     player.start();
     }


  protected void onDraw(Canvas canvas) {
      super.onDraw(canvas);
      if (mBytes == null) {
       return;
      }
      if (mPoints == null || mPoints.length < mBytes.length * 4) {
       mPoints = new float[mBytes.length * 4];
      }
      mRect.set(0, 0, getWidth(), getHeight());
      for (int i = 0; i < mBytes.length - 1; i++) {
       mPoints[i * 4] = mRect.width() * i / (mBytes.length - 1);
       mPoints[i * 4 + 1] = mRect.height() / 2
         + ((byte) (mBytes[i] + 128)) * (mRect.height() / 2) / 128;
       mPoints[i * 4 + 2] = mRect.width() * (i + 1) / (mBytes.length - 1);
       mPoints[i * 4 + 3] = mRect.height() / 2
         + ((byte) (mBytes[i + 1] + 128)) * (mRect.height() / 2)
         / 128;
      }
      canvas.drawColor(Color.WHITE);
      canvas.drawLines(mPoints, mForePaint);
     }
@Override
public void surfaceCreated(SurfaceHolder holder) {
    // TODO Auto-generated method stub
    _thread.setRunning(true);
    _thread.start();
    initAudio();
}
@Override
public void surfaceChanged(SurfaceHolder holder, int format, int width,
        int height) {
    // TODO Auto-generated method stub

}
@Override
public void surfaceDestroyed(SurfaceHolder holder) {
    // TODO Auto-generated method stub
      boolean retry = true;
        _thread.setRunning(false);
        while (retry) {
            try {
                _thread.join();
                retry = false;
            } catch (InterruptedException e) {
                // we will try it again and again...
            }
        }

}

public void clean(){
     if(player!=null){
            visualizer.release();
            player.release();
            player= null;

        }
}

private void setupVisualizerFxAndUI(){
    Equalizer mEqualizer = new Equalizer(0, player.getAudioSessionId());

    mEqualizer.setEnabled(false);
      visualizer =new Visualizer(player.getAudioSessionId());
      visualizer.setCaptureSize(Visualizer.getCaptureSizeRange()[1]);
     visualizer.setDataCaptureListener(new Visualizer.OnDataCaptureListener() {

        @Override
        public void onWaveFormDataCapture(Visualizer visualizer, byte[] waveform,
                int samplingRate) {
            // TODO Auto-generated method stub
          updateVisualizer(waveform);


        }

        @Override
        public void onFftDataCapture(Visualizer visualizer, byte[] fft,
                int samplingRate) {
            // TODO Auto-generated method stub

        }
    },Visualizer.getMaxCaptureRate()/2,true,false) ;
//   Log.d(Tag,String.valueOf(Visualizer.getMaxCaptureRate()));

}}

主题类：

public class SurfaceThread extends Thread {
  private SurfaceHolder surfaceHolder;
    private VisualizerView panel;
    private boolean run = false;

    public SurfaceThread(SurfaceHolder surfaceHolder, VisualizerView panel) {
     this.   surfaceHolder = surfaceHolder;
       this. panel = panel;
    }

    public void setRunning(boolean run) {
        this.run = run;
    }

    @Override
    public void run() {

         Canvas c;
            while (run) {
                c = null;
                try {
                    c = surfaceHolder.lockCanvas(null);
                    synchronized (surfaceHolder) {

                        panel.onDraw(c);
                    }
                } finally {
                    // do this in a finally so that if an exception is thrown
                    // during the above, we don't leave the Surface in an
                    // inconsistent state
                    if (c != null) {
                        surfaceHolder.unlockCanvasAndPost(c);
                    }
                }
            }


    }}

现在问题是应用程序在运行两次后会崩溃。我知道我是 没有正确传递数据：

public void onWaveFormDataCapture(Visualizer visualizer, byte[] waveform,
                int samplingRate) {
            // TODO Auto-generated method stub
          updateVisualizer(waveform);


        }

那么，我该如何管理呢？ 此外，我对哪个线程可视化工具/媒体播放器正在运行以及应该去哪里感到困惑？