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 stub
		this.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  
	}
	@Override
	public void surfaceCreated(SurfaceHolder holder) {
		// TODO Auto-generated method stub
		Log.i(tag, "=================surfaceCreated======================");
		icon =getImage(context,R.drawable.icon);
                rect=new Rect(0,0,icon.getWidth(),icon.getHeight());//图片的rect
		paint=new Paint();
		
		running=true;
		new Thread(this).start();
		
	}

	@Override
	public void surfaceDestroyed(SurfaceHolder holder) {
		// TODO Auto-generated method stub
		Log.i(tag, "=================surfaceDestroyed======================");
		running=false;
	}
	
	@Override
	public void surfaceChanged(SurfaceHolder holder, int format, int width,
			int height) {
		// TODO Auto-generated method stub
		Log.i(tag, "=================surfaceChanged======================");
		
	}
	
	@Override
	public void run() {
		// TODO Auto-generated method stub
		int 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rect
	private 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
	@Override
	public boolean onTouch(View v, MotionEvent event) {
		// TODO Auto-generated method stub
		switch (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);  
	}  
	
}

//在Activity中调用：
public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        AppView view=new AppView(this);
        setContentView(view);
}