在SurfaceView上拖动一张小图片
用手指随便拖。这里采用了线程去绘制，其实也可以在onTouch中绘制。
import android.content.Context;import android.graphics.Bitmap;import android.graphics.BitmapFactory;import android.graphics.Canvas;import android.graphics.Color;import android.graphics.Paint;import android.graphics.Point;import android.graphics.Rect;import android.graphics.Region;import android.util.Log;import android.view.MotionEvent;import android.view.SurfaceHolder;import android.view.SurfaceView;import android.view.View;import android.view.View.OnTouchListener;import com.ql.app.R;public class AppView extends SurfaceView implements SurfaceHolder.Callback,Runnable,OnTouchListener{private static final String tag="AppView";private Context context;private SurfaceHolder holder;private Bitmap icon;private Paint paint;private boolean running=true;public AppView(Context context) {super(context);// TODO Auto-generated constructor stubthis.context=context;holder = this.getHolder();//获取holder holder.addCallback(this); this.setOnTouchListener(this); }private void init(){}private void close(){}private void logic(){}private void draw(){ Canvas canvas = holder.lockCanvas();//获取画布 canvas.drawColor(Color.BLACK); canvas.drawBitmap(icon, rect.left,rect.top,null); holder.unlockCanvasAndPost(canvas);// 解锁画布，提交画好的图像 }@Overridepublic void surfaceCreated(SurfaceHolder holder) {// TODO Auto-generated method stubLog.i(tag, "=================surfaceCreated======================");icon =getImage(context,R.drawable.icon); rect=new Rect(0,0,icon.getWidth(),icon.getHeight());//图片的rectpaint=new Paint();running=true;new Thread(this).start();}@Overridepublic void surfaceDestroyed(SurfaceHolder holder) {// TODO Auto-generated method stubLog.i(tag, "=================surfaceDestroyed======================");running=false;}@Overridepublic void surfaceChanged(SurfaceHolder holder, int format, int width,int height) {// TODO Auto-generated method stubLog.i(tag, "=================surfaceChanged======================");}@Overridepublic void run() {// TODO Auto-generated method stubint SLEEP_TIME=100;while (running) {long start=System.currentTimeMillis();logic();draw(); long end=System.currentTimeMillis(); if(end-start<SLEEP_TIME){ try { Thread.sleep(SLEEP_TIME-(end-start)); } catch (InterruptedException e) { // TODO Auto-generated catch block e.printStackTrace(); } } }}//Region region=new Region();private Point point=new Point();//点击点private Rect rect;//图片的rectprivate boolean canDrag=false;//判断是否点击在图片上，否则拖动无效private int offsetX=0,offsetY=0;//点击点离图片左上角的距离@Overridepublic boolean onTouch(View v, MotionEvent event) {// TODO Auto-generated method stubswitch (event.getAction()) {case MotionEvent.ACTION_DOWN:point.x=(int)event.getX();point.y=(int)event.getY();if(rect.contains(point.x, point.y)){canDrag=true;offsetX=point.x-rect.left;offsetY=point.y-rect.top;}break;case MotionEvent.ACTION_MOVE:if(canDrag){rect.left=(int)event.getX()-offsetX;rect.top=(int)event.getY()-offsetY;rect.right=rect.left+icon.getWidth();rect.bottom=rect.top+icon.getHeight();if (rect.left < 0) { rect.left = 0;rect.right = rect.left+icon.getWidth(); } if (rect.right > getMeasuredWidth()) { rect.right = getMeasuredWidth(); rect.left = rect.right-icon.getWidth(); } if (rect.top < 0) { rect.top = 0; rect.bottom = rect.top+icon.getHeight(); } if (rect.bottom > getMeasuredHeight()) { rect.bottom = getMeasuredHeight(); rect.top = rect.bottom-icon.getHeight(); }}break;case MotionEvent.ACTION_UP:canDrag=false;break;default:break;}return true;}//****************************************************************************public static final Bitmap getImage(Context context, int imageId) { return BitmapFactory.decodeResource(context.getResources(),imageId); } }