何为脏矩形?比如surfaceview上绘制旋转图片的时候,只刷新一个特定的矩形区域就可以了。这个矩形区域就是脏矩形。在surfaceview上  canvas = holder.lockCanvas(new Rect(0, 0, 130, 130)); //获取画布 像这种带rect参数的就是脏矩形的刷新。 请看源码: ~~~ package yan.guoqi.rectphoto; import android.content.Context; import android.graphics.Bitmap; import android.graphics.BitmapFactory; import android.graphics.Canvas; import android.graphics.Matrix; import android.graphics.Paint; import android.graphics.PixelFormat; import android.graphics.Rect; import android.util.AttributeSet; import android.util.Log; import android.view.SurfaceHolder; import android.view.SurfaceView; public class DrawSurfaceView extends SurfaceView implements SurfaceHolder.Callback{ private static final String tag2 = "DrawSV"; private boolean runFlag = true; protected SurfaceHolder holder; private Bitmap rotateImg; private Thread myThread; public DrawSurfaceView(Context context, AttributeSet attrs) //构造函数 { super(context, attrs); // TODO Auto-generated constructor stub rotateImg = BitmapFactory.decodeResource(getResources(), R.drawable.rotate_circle); rotateImg = Bitmap.createScaledBitmap(rotateImg, 100, 100, true); holder = this.getHolder(); holder.addCallback(this); holder.setFormat(PixelFormat.TRANSPARENT); //顶层绘制SurfaceView设成透明 this.setZOrderOnTop(true); myThread = new Thread(new MyThread()); } public void surfaceChanged(SurfaceHolder arg0, int arg1, int arg2, int arg3) { // TODO Auto-generated method stub Log.v(tag2, "DrawSV:surfaceChanged..."); } public void surfaceCreated(SurfaceHolder arg0) { // TODO Auto-generated method stub Log.v(tag2, "DrawSV:surfaceCreated..."); //启动自定义线程 myThread.start(); } public void surfaceDestroyed(SurfaceHolder arg0) { // TODO Auto-generated method stub Log.v(tag2, "DrawSV:surfaceDestroyed..."); //终止自定义线程 runFlag = false; myThread.interrupt(); } /*自定义线程*/ class MyThread implements Runnable{ public void run() { // TODO Auto-generated method stub Canvas canvas = null; int rotate = 0; while(runFlag){ try { canvas = holder.lockCanvas(new Rect(0, 0, 130, 130)); //获取画布 Paint paint = new Paint(); //canvas.drawBitmap(rotateImg, 0, 0, paint); //绘制旋转的背景 //创建矩阵控制图片旋转和平移 Matrix matrix = new Matrix(); //设置旋转角度 matrix.postRotate((rotate += 48) % 360, rotateImg.getWidth() / 2, rotateImg.getHeight() / 2); //设置左边距和上边距 matrix.postTranslate(0, 0); //绘制旋转图片 canvas.drawBitmap(rotateImg, matrix, paint); //休眠控制最大帧率为每秒3绘制30次 Thread.sleep(30); holder.unlockCanvasAndPost(canvas);//解锁画布,提交画好的图像 } catch (Exception e) { // TODO: handle exception Log.v(tag2, "DrawSurfaceView:绘制失败..."); } } } } } ~~~ **需要注意的几点:** 第一,就是如何安全中止一个线程。这里通过设置标志位来实现。因为自带的stop()方法不安全,android本身都不推荐。关于如何安全中止线程可以参考这里:http://www.iteye.com/problems/67052 http://www.dewen.org/q/1957 第二,holder.unlockCanvasAndPost(canvas);//解锁画布,提交画好的图像 这句话必须和                    canvas = holder.lockCanvas(new Rect(0, 0, 130, 130)); //获取画布  在一个{ }里。像这里的http://www.cnblogs.com/jqyp/archive/2012/01/01/2309692.html的做法在程序退出时会抛出异常。原因是线程中止的时候无法再解锁画布了。 第三,利用Matrix让图片旋转的核心代码: ~~~ //创建矩阵控制图片旋转和平移 Matrix matrix = new Matrix(); //设置旋转角度 matrix.postRotate((rotate += 48) % 360, rotateImg.getWidth() / 2, rotateImg.getHeight() / 2); //设置左边距和上边距 matrix.postTranslate(0, 0); //绘制旋转图片 canvas.drawBitmap(rotateImg, matrix, paint); //休眠控制最大帧率为每秒3绘制30次 Thread.sleep(30); ~~~ 第四,之所以将此surfaceview设成顶层透明,原因是杂家想探索在底层surfaceview预览摄像头视频的时候,在顶层的surfaceview绘制一个旋转的图片动画。但遗憾的是,图片确实是旋转了,底层的摄像头预览也正常。但就是旋转的图片将预览画面挡住了。**唉,看来前文http://blog.csdn.net/yanzi1225627/article/details/8580034这里的360扫描二维码的界面不是通过这种思路实现的,抑或是 我旋转的图片不是透明的???  ****