点击视图中的图片拖动位置

代码如下，不做分析，请看注释：

一般配置如下的主题

android:theme="@android:style/Theme.Black.NoTitleBar.Fullscreen"

public class MySurfaceView extends SurfaceView {private SurfaceHolder holder ;private Bitmap icBitmap ;private DrawThread thread ;boolean isMove = false ;private float cx , cy ;//当前图片的位置坐标private float ex , ey ;//事件发生的位置坐标int vw,vh,bw,bh ;//窗口的长宽和图片的长宽public MySurfaceView(Context context) {this(context,null) ;}public MySurfaceView(Context context, AttributeSet attrs) {super(context, attrs);init();holder = getHolder() ;holder.addCallback(callback);}private void init() {icBitmap = BitmapFactory.decodeResource(getResources(), R.drawable.ic_launcher) ; }private Callback callback = new Callback() {//当SurfaceView被从窗口剥离后会调用此方法//回收资源，和停止线程@Overridepublic void surfaceDestroyed(SurfaceHolder holder) {thread.interrupt();icBitmap.recycle();}//当SurfaceView被创建后会调用此方法//绘制线程的启动@Overridepublic void surfaceCreated(SurfaceHolder holder) {//得到屏幕的长宽vw = holder.getSurfaceFrame().width() ;vh = holder.getSurfaceFrame().height() ;//得到图片的长宽bw = icBitmap.getWidth() ;bh = icBitmap.getHeight() ;if(thread == null){thread = new DrawThread() ;}thread.start(); }//SurfaceView 的大小发生改变的时候调用此方法@Overridepublic void surfaceChanged(SurfaceHolder holder, int format, int width,int height) {}};final class DrawThread extends Thread{@Overridepublic void run() {Matrix m = new Matrix() ;while(!isInterrupted()){//不能超出屏幕范围，超过了固定在边沿if(cx > vw - bw)cx = vw -bw ;if(cy > vh - bh)cy = vh -bh ;m.setTranslate(cx, cy); Canvas c = holder.lockCanvas() ;if (c == null)break ;c.drawColor(Color.BLACK); c.drawBitmap(icBitmap, m, null);  //c.drawBitmap(icBitmap, cx, cy, null); //对画布进行解锁和调用postInvalidate()holder.unlockCanvasAndPost(c); }}}        //触摸屏幕调用的方法        @Overridepublic boolean onTouchEvent(MotionEvent event) {ex = event.getX() ;ey = event.getY() ;int action = event.getAction() ;switch(action){case MotionEvent.ACTION_DOWN://判断事件的点击是否发生在图片上if(cx<ex && ex<cx + bw &&cy<ey && ey <cy + bh)isMove = true ;break ;case MotionEvent.ACTION_UP:isMove = false ;break ;case MotionEvent.ACTION_MOVE :if(isMove == true){cx = ex ;cy = ey ;}break ;}return true ;}}