Android 游戏开发 SurfaceView框架

SurfaceView和View的明显不同在于Surface不需要通过线程来更新视图，但在绘制之前必须使用lockCanvas方法锁定画布，并得 到画布，然后绘制，完成后用unlockCanvasAndPost方法解锁画布。SurfaceView类的事件处理和View一样。
绘制界面的类：

   1. package com.yarin.android.Examples_05_02;  
   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.SurfaceHolder;  
   8. import android.view.SurfaceView;  
   9.   
  10. public class GameSurfaceView extends SurfaceView  
  11.    
  12.                             implements SurfaceHolder.Callback,Runnable  
  13. {  
  14.     //控制循环  
  15.     boolean            mbLoop            = false;  
  16.      
  17.     //定义SurfaceHolder对象  
  18.     SurfaceHolder    mSurfaceHolder    = null;  
  19.     int                miCount            = 0;  
  20.     int                y                = 50;  
  21.   
  22.   
  23.     public GameSurfaceView(Context context)  
  24.     {  
  25.         super(context);  
  26.   
  27.         // 实例化SurfaceHolder  
  28.         mSurfaceHolder = this.getHolder();  
  29.   
  30.         // 添加回调  
  31.         mSurfaceHolder.addCallback(this);  
  32.         this.setFocusable(true);  
  33.   
  34.         mbLoop = true;  
  35.     }  
  36.   
  37.   
  38.     // 在surface的大小发生改变时激发  
  39.     public void surfaceChanged(SurfaceHolder holder, int format, int width, int height)  
  40.     {  
  41.   
  42.     }  
  43.   
  44.     // 在surface创建时激发  
  45.     public void surfaceCreated(SurfaceHolder holder)  
  46.     {  
  47.         //开启绘图线程  
  48.         new Thread(this).start();  
  49.     }  
  50.   
  51.     // 在surface销毁时激发  
  52.     public void surfaceDestroyed(SurfaceHolder holder)  
  53.     {  
  54.         // 停止循环  
  55.         mbLoop = false;  
  56.     }  
  57.   
  58.     // 绘图循环  
  59.     public void run()  
  60.     {  
  61.         while (mbLoop)  
  62.         {  
  63.             try  
  64.             {  
  65.                 Thread.sleep(200);  
  66.             }  
  67.             catch (Exception e)  
  68.             {  
  69.                  
  70.             }  
  71.             synchronized( mSurfaceHolder )  
  72.             {  
  73.                 Draw();  
  74.             }  
  75.              
  76.         }  
  77.     }  
  78.   
  79.     // 绘图方法  
  80.     public void Draw()  
  81.     {  
  82.         //锁定画布，得到canvas  
  83.         Canvas canvas= mSurfaceHolder.lockCanvas();  
  84.   
  85.         if (mSurfaceHolder==null || canvas == null )  
  86.         {  
  87.             return;  
  88.         }  
  89.          
  90.         if (miCount < 100)  
  91.         {  
  92.             miCount++;  
  93.         }  
  94.         else  
  95.         {  
  96.             miCount = 0;  
  97.         }  
  98.         // 绘图  
  99.         Paint mPaint = new Paint();  
 100.         mPaint.setAntiAlias(true);  
 101.         mPaint.setColor(Color.BLACK);  
 102.         //绘制矩形--清屏作用  
 103.         canvas.drawRect(0, 0, 320, 480, mPaint);  
 104.         switch (miCount % 4)  
 105.         {  
 106.         case 0:  
 107.             mPaint.setColor(Color.BLUE);  
 108.             break;  
 109.         case 1:  
 110.             mPaint.setColor(Color.GREEN);  
 111.             break;  
 112.         case 2:  
 113.             mPaint.setColor(Color.RED);  
 114.             break;  
 115.         case 3:  
 116.             mPaint.setColor(Color.YELLOW);  
 117.             break;  
 118.         default:  
 119.             mPaint.setColor(Color.WHITE);  
 120.             break;  
 121.         }  
 122.          
 123.         canvas.drawCircle((320 - 25) / 2, y, 50, mPaint);  
 124.         // 绘制后解锁，绘制后必须解锁才能显示  
 125.         mSurfaceHolder.unlockCanvasAndPost(canvas);  
 126.     }  
 127. }