Canvas.drawBitmap或Canvas.drawColor不工作

Question

我需要在Surfaceview上以15fps的速度绘制位图，我的SurfaceView如下所示

public class RawVideoViewSV extends SurfaceView implements SurfaceHolder.Callback{

private boolean isSurface;
private Bitmap mBitmap;
private SurfaceHolder holder;

public RawVideoViewSV(Context context, AttributeSet attrs) {
    super(context, attrs);
    // TODO Auto-generated constructor stub
     holder = getHolder();
     holder.addCallback(this); 
}


@Override
public void surfaceChanged(SurfaceHolder holder, int format, int width,
        int height) {
    // TODO Auto-generated method stub
    isSurface = false;
}

@Override
public void surfaceCreated(SurfaceHolder holder) {
    // TODO Auto-generated method stub
    isSurface = true;
}

@Override
public void surfaceDestroyed(SurfaceHolder holder) {
    // TODO Auto-generated method stub
    isSurface = false;
}

public SurfaceHolder getSurfaceHolder(){
    return holder;
}

@Override
protected void onDraw(Canvas canvas) {
    // TODO Auto-generated method stub
    if(isSurface){
        canvas.drawColor(Color.GREEN);
        if(mBitmap != null)
            canvas.drawBitmap(mBitmap, 0, 0, null);
    }
}


public void doDraw(Canvas canvas,Bitmap bmp) {
    // TODO Auto-generated method stub
    System.out.println("RawVideoViewSV---> doDraw isSurface = " + isSurface + bmp.getHeight());
    Rect source = new Rect(0, 0, bmp.getWidth(), bmp.getHeight());
    if(isSurface){
        canvas.drawColor(Color.GREEN);
        if(bmp != null)
            canvas.drawBitmap(bmp, null,source, null);
    }
}}

在我的活动中，我创建了位图，并将其传递到Surface上进行绘制，但由于某种原因，canvas.drawcolor和canvas.drawbitmap都无法在surfacview中工作。

rawVideoViewSV0 = (RawVideoViewSV) findViewById(R.id.videoRawViewSV0);
Bitmap bmpx = Bitmap.createBitmap(rgb, videoSample.getWidth(),
videoSample.getHeight(),Bitmap.Config.ARGB_8888);
    Canvas mCanvas = null;
    SurfaceHolder mHolder = rawVideoViewSV0.getHolder();

    try {
        mCanvas = mHolder.lockCanvas();
        synchronized (mHolder) {    
            rawVideoViewSV0.doDraw(mCanvas,bmpx);
        }
    } finally {                   
        if (mCanvas != null) {
            mHolder.unlockCanvasAndPost(mCanvas);
        }
    }

rawVideoViewSV0的类型为RawVideoViewSV。我已经验证了我的位图不是空的，只是在第一次调用onDraw时，表面视图显示为绿色，仅此而已。

有人能告诉我哪里出问题了吗？

Answer 1

SurfaceView包含两个部分，即曲面和视图。视图是与UI的其余部分一起绘制的，但通常只是一个用于布局目的的透明“孔”。曲面显示在UI下方的单独图层上。

看起来你是在把视频帧写到Surface上，然后用绿色的实心视图覆盖它们。删除onDraw()函数(为View part获取画布)，并在doDraw()中执行所有操作(为Surface part获取画布)。