SurfaceView启发代码

import java.util.Random;  
  
import Android.app.Activity;  
import android.content.Context;  
import android.graphics.Canvas;  
import android.graphics.Color;  
import android.graphics.Paint;  
import android.os.Bundle;  
import android.view.MotionEvent;  
import android.view.SurfaceHolder;  
import android.view.SurfaceHolder.Callback;  
import android.view.SurfaceView;  
import android.view.Window;  
import android.view.WindowManager;  
  
public class BallActivity extends Activity {  
    @Override  
    public void onCreate(Bundle savedInstanceState) {  
        super.onCreate(savedInstanceState);  
        //设置全屏   
        requestWindowFeature(Window.FEATURE_NO_TITLE);  
        this.getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN,  
                WindowManager.LayoutParams.FLAG_FULLSCREEN);  
          
        setContentView(new BallSurfaceView(this));  
    }  
      
    class BallSurfaceView extends SurfaceView implements Callback,Runnable{  
        private int screenW;        //屏幕宽度   
        private int screenH;        //屏幕高度   
        private Paint paint;        //定义画笔   
        private float cx = 50;      //圆点默认X坐标   
        private float cy = 50;      //圆点默认Y坐标   
        private int radius = 20;  
        //定义颜色数组   
        private int colorArray[] = {Color.BLACK,Color.BLACK,Color.GREEN,Color.YELLOW, Color.RED};  
        private int paintColor = colorArray[0]; //定义画笔默认颜色   
        private Canvas canvas = null; //定义画布   
        private Thread th = null;     //定义线程   
        private SurfaceHolder sfh = null;  
          
        public BallSurfaceView(Context context){  
            super(context);  
            /*备注1：在此处获取屏幕高、宽值为0，觉得此时view还未被建立， 
             * 在接口Callback的surfaceCreated方法中view才被建立 
             */  
            /*screenW = getWidth(); 
            screenH = getHeight();*/  
              
            //初始化画笔   
            initPaint();  
            sfh = getHolder();  
            sfh.addCallback(this);  
            th = new Thread(this);  
        }  
          
        @Override  
        public void surfaceCreated(SurfaceHolder holder) {  
            //获取屏幕宽度   
            screenW = getWidth();  
            //获取屏幕高度   
            screenH = getHeight();  
            //启动绘图线程   
            th.start();  
        }  
          
        private void initPaint(){  
            paint = new Paint();  
            //设置消除锯齿   
            paint.setAntiAlias(true);  
            //设置画笔颜色   
            paint.setColor(paintColor);  
        }  
          
        @Override  
        public void run() {  
            while(true){  
                try{  
                    myDraw();   
                    Thread.sleep(100);  
                }catch(InterruptedException e){  
                    e.printStackTrace();  
                }  
            }  
        }  
          
        /*备注2：切记，在自定SurfaceView中定义的myDraw方法，自定义View（继承自View的子类）中的onDraw方法 
         * 彻底是两码事： 
         * 1）自定义View（继承自View的子类）中的onDraw方法是重写父类的onDraw方法，在调用postInvalidate后会自动回调该onDraw()方法。 
         * 2）此处的myDraw方法须要手动调用，因此此处故意将方法命名为myDraw，突出为该方法是本身写的，非重写父类的方法 。 
         *  
         */  
        //重写onDraw方法实现绘图操做   
        protected void myDraw() {  
            //获取canvas实例   
            canvas = sfh.lockCanvas();  
            //将屏幕设置为白色   
            canvas.drawColor(Color.WHITE);  
            //修正圆点坐标   
            revise();  
            //随机设置画笔颜色   
            setPaintRandomColor();  
            //绘制小圆做为小球   
            canvas.drawCircle(cx, cy, radius, paint);  
            //将画好的画布提交   
            sfh.unlockCanvasAndPost(canvas);  
        }  
          
        //为画笔设置随机颜色   
        private void setPaintRandomColor(){  
            Random rand = new Random();  
            int randomIndex = rand.nextInt(colorArray.length);  
            paint.setColor(colorArray[randomIndex]);  
        }  
          
        //修正圆点坐标   
        private void revise(){  
            if(cx <= radius){  
                cx = radius;  
            }else if(cx >= (screenW-radius)){  
                cx = screenW-radius;  
            }  
            if(cy <= radius){  
                cy = radius;  
            }else if(cy >= (screenH-radius)){  
                cy = screenH-radius;  
            }  
        }  
          
        @Override  
        public boolean onTouchEvent(MotionEvent event) {  
            switch (event.getAction()) {  
            case MotionEvent.ACTION_DOWN:  
                // 按下   
                cx = (int) event.getX();  
                cy = (int) event.getY();  
                break;  
            case MotionEvent.ACTION_MOVE:  
                // 移动   
                cx = (int) event.getX();  
                cy = (int) event.getY();  
                break;  
            case MotionEvent.ACTION_UP:  
                // 抬起   
                cx = (int) event.getX();  
                cy = (int) event.getY();  
                break;  
            }  
              
            /* 
             * 备注1：次处必定要将return super.onTouchEvent(event)修改成return true，缘由是： 
             * 1）父类的onTouchEvent(event)方法可能没有作任何处理，可是返回了false。 
             * 2)一旦返回false，在该方法中不再会收到MotionEvent.ACTION_MOVE及MotionEvent.ACTION_UP事件。 
             */  
            //return super.onTouchEvent(event);   
            return true;    
        }  
          
        @Override  
        public void surfaceChanged(SurfaceHolder holder, int format, int width,  
                int height) {  
              
        }  
          
        @Override  
        public void surfaceDestroyed(SurfaceHolder holder) {  
              
        }  
          
    }  
} 

本篇文章来源于 Linux公社网站(www.linuxidc.com)  原文连接：http://www.linuxidc.com/Linux/2011-10/44495.htm