Android collision detection - Region collision check

 

Region collision detection

 

Region class in android development techniques are often used, especially in such a judging whether a rectangular area function - Region. contains (int x, int y) are often used .

 

to an example below :

 

  

package com.example.collidedemo; 
 
import android.content.Context; 
import android.graphics.Canvas; 
import android.graphics.Color; 
import android.graphics.Paint; 
import android.graphics.Paint.Style; 
import android.graphics.Rect; 
import android.graphics.Region; 
import android.util.Log; 
import android.view.MotionEvent; 
import android.view.SurfaceHolder; 
import android.view.SurfaceHolder.Callback; 
import android.view.SurfaceView; 
 
public class RegionSurfaceView extends SurfaceView implements Callback,Runnable { 
    Paint paint; 
    SurfaceHolder surfaceHolder; 
    Thread thread; 
    boolean flag; 
    int sleeptime=100; 
    boolean isCollsion; 
    /*定义一个矩形*/ 
    Rect rect=new Rect(0, 0, 100, 100); 
    /*定义一个Region*/ 
    Region region=new Region(rect); 
    public RegionSurfaceView(Context context) { 
        super(context); 
        paint=new Paint(); 
        paint.setStyle(Style.STROKE); 
        paint.setAntiAlias(true); 
        surfaceHolder=getHolder(); 
        surfaceHolder.addCallback(this);     
        thread=new Thread(this); 
    } 
     
    private void mydraw(Canvas canvas){ 
        canvas.drawColor(Color.WHITE); 
        canvas.drawRect(rect, paint); 
        if(isCollsion){ 
            paint.setColor(Color.RED); 
            canvas.drawText("点击碰撞了", 10, 10, paint); 
        } 
        else{ 
            paint.setColor(Color.BLACK); 
            canvas.drawText("没有碰撞了", 10, 10, paint); 
        } 
    } 
     
     
    /** 
     * 触点事件 
     */ 
    @Override 
    public boolean onTouchEvent(MotionEvent event){ 
        if(region.contains((int)event.getX(), (int)event.getY())){ 
            isCollsion=true; 
        } 
        else{ 
            isCollsion=false; 
        } 
        return super.onTouchEvent(event); 
    } 
     
    @Override 
    public void run() { 
        Canvas canvas=null; 
        while (flag) { 
            try { 
                canvas=surfaceHolder.lockCanvas(); 
                synchronized (canvas) { 
                    mydraw(canvas); 
                } 
            } catch (Exception e) { 
                Log.e("region",e.getMessage()); 
            } 
            finally{ 
                if(canvas!=null){ 
                    surfaceHolder.unlockCanvasAndPost(canvas); 
                } 
            } 
            try { 
                Thread.sleep(sleeptime); 
            } catch (Exception e) { 
                Log.e("region",e.getMessage()); 
            } 
        } 
         
    } 
 
    @Override 
    public void surfaceCreated(SurfaceHolder holder) { 
        flag=true; 
        if(!thread.isAlive()){ 
            thread.start(); 
        } 
    } 
 
    @Override 
    public void surfaceChanged(SurfaceHolder holder, int format, int width, 
            int height) { 
        // TODO Auto-generated method stub 
         
    } 
 
    @Override 
    public void surfaceDestroyed(SurfaceHolder holder) { 
        flag=true; 
    } 
 
}