Android跟随手指运动的小球 …

[java]  view plain copy

1. package yuhee.mars;  
2.   
3. import android.content.Context;  
4. import android.graphics.Canvas;  
5. import android.graphics.Color;  
6. import android.graphics.Paint;  
7. import android.view.View;  
8.   
9.   
10. public class DrawView  extends View{  
11.           
12.           
13.           
14.   
15.         public float currentx = 40 ;  
16.         public  float currenty = 50 ;  
17.           
18.         public DrawView(Context context) {  
19.                 super(context);  
20.                 // TODO Auto-generated constructor stub  
21.         }  
22.         @Override  
23.         protected void onDraw(Canvas canvas) {  
24.                 // TODO Auto-generated method stub  
25.                 super.onDraw(canvas);  
26.                 //创建画笔 ;  
27.                 Paint p = new Paint() ;  
28.                 p.setColor(Color.GREEN) ;  
29.                 //绘制一个小球 ；  
30.                 canvas.drawCircle(currentx, currenty, 15, p) ;  
31.     }  
32.         }  

下面是该应用的Activity类：

 

[java]  view plain copy

1. package yuhee.mars;  
2.   
3. import android.app.Activity;  
4. import android.os.Bundle;  
5. import android.view.MotionEvent;  
6. import android.view.View;  
7. import android.view.View.OnTouchListener;  
8. import android.widget.LinearLayout;  
9.   
10. public class Activity_06Activity extends Activity {  
11.       
12.     @Override  
13.             public void onCreate(Bundle savedInstanceState) {  
14.         super.onCreate(savedInstanceState);  
15.         setContentView(R.layout.main);  
16.         LinearLayout main = (LinearLayout)findViewById(R.id.root) ;  
17.         final DrawView draw = new DrawView(this) ;  
18.         draw.setMinimumWidth(300) ;  
19.         draw.setMinimumHeight(500) ;  
20.         draw.setOnTouchListener(new OnTouchListener()  
21.         {  
22.   
23.                         @Override  
24.                         public boolean onTouch(View arg0, MotionEvent event) {  
25.                                 // TODO Auto-generated method stub  
26.                                 draw.currentx = event.getX() ;  
27.                                 draw.currenty = event.getY() ;  
28.                                 //通知Draw组件重绘 ;  
29.                                 draw.invalidate() ;  
30.                                 return true ;  
31.                                   
32.                         }  
33.                   
34.         }) ;  
35.         main.addView(draw) ;  
36.         }  
37. }  

看下效果图：欢迎各位拍砖