1.小球类

 

package com.android.ballmove;

import android.graphics.Bitmap;

import android.graphics.BitmapFactory;

import android.graphics.Canvas;

import android.graphics.Paint;

public class Ball {

 /** 

 18.          * 球的高 

 19.          */ 

          public static final int HEIGHT = 93;  

          /** 

 22.          * 球的宽 

 23.          */ 

          public static final int WIDTH = 93;  

          private static final int STEPLENGTH = 10;//每次运动的间距  

          private static final float REDUCEPERCENTAGE =  0.35F;//递减系数  

          private int stepReduce ;//每次反向运动的缩短的距离  

           

          private float runX ;//球的位置  

          private float runY ;//球的位置  

         private BallSurfaceView bsv ;  

          private boolean upDirection = false;//if true,up direction,or is down direction  

          private float maxHeight ;//当前运动最高的高度  

          private Paint paint ;  

           

          Bitmap ballBitmap ;//球的图片  

          SportActivity sa ;  

          public Ball(float initX , float initY , BallSurfaceView bsv){  

                    this.runX  = initX;  

                    this.runY = initY ;  

                    maxHeight = initY;  

                    this.bsv = bsv;  

                    ballBitmap = BitmapFactory.decodeResource(bsv.getResources(), R.drawable.ball);//加载图片  

                    paint = new Paint();  

                    sa = bsv.sportActivity;  

          }  

           

          public void onDraw(Canvas canvas) {  

                    int c = paint.getColor();//保存颜色，之后还原为之前颜色  

                    boundaryTest();  

                    if(canvas != null) canvas.drawBitmap(ballBitmap,runX,runY,paint);  

                    paint.setColor(c);  

                    move();  

         }  

         /** 

 56.          * 运动 

 57.          */ 

          private void move() {  

                    if(maxHeight >= (sa.screenHeight - HEIGHT)) {  

                             return;  

                   }  

                   if(upDirection){//向上  

                             runY = runY + STEPLENGTH ;  

                    }else{  

                             runY = runY - STEPLENGTH ;  

                    }  

          }  

    

          /** 

 70.          * 边界检测，使球不会飞出边界 

 71.          */ 

          private void boundaryTest(){  

    

                    if(runY > sa.screenHeight - HEIGHT){//向下运动到头  

                           upDirection = !upDirection;//方向置反  

                             runY = sa.screenHeight - HEIGHT;  

                             stepReduce = (int) (maxHeight * REDUCEPERCENTAGE);  

                             maxHeight = maxHeight + stepReduce ;//最大高度递减  

                              

                   }  

                    if(runY < maxHeight ){//向上运动到头  

                            upDirection = !upDirection;//方向置反  

                            if(maxHeight >= (sa.screenHeight - HEIGHT)) return;  

                             runY = maxHeight ;  

                              

                   }  

         }  

 } 

 

2.小球弹跳的过程

 

package com.android.ballmove;

import android.content.Context;

import android.graphics.Canvas;

import android.graphics.Color;

import android.graphics.Paint;

import android.view.SurfaceHolder;

import android.view.SurfaceView;

public class BallSurfaceView extends SurfaceView implements SurfaceHolder.Callback{  

         SportActivity sportActivity ;//调用该SurfaceView的上下文引用  

         private Ball ball ;//小球  

         SurfaceHolder holder ;  

          

        public BallSurfaceView(Context context) {  

                   super(context);  

                   this.sportActivity = (SportActivity)context ;  

                   ball = new Ball(100, 100, this);  

                   holder = this.getHolder();  

                   holder.addCallback(this);  

         }  

   

         @Override 

         protected void onDraw(Canvas canvas) {  

                   super.onDraw(canvas);  

                    

                   if(canvas == null) canvas = holder.lockCanvas();//锁定画布  

                   Paint p = new Paint();  

                   int c = p.getColor();  

                   p.setColor(Color.GRAY);//设置背景白色  

                   if(canvas != null)  

                   canvas.drawRect(0, 0, sportActivity.screenWidth, sportActivity.screenHeight, p);  

                   p.setColor(c);  

                   ball.onDraw(canvas);  

                   holder.unlockCanvasAndPost(canvas);//释放锁  

         }  

   

         @Override 

         public void surfaceChanged(SurfaceHolder holder, int format, int width,                               int height) {  

                    

         }      

         @Override 

         public void surfaceCreated(SurfaceHolder holder) {  

                   new RefreshThread().start();  

         }  

   

         @Override 

         public void surfaceDestroyed(SurfaceHolder holder) {  

                    

        }  

          

         private class RefreshThread extends Thread{  

   

                   @Override 

                   public void run() {  

   

                           while(true){  

                                     Canvas canvas = null;  

                                     try{  

                                              onDraw(canvas);  

                                     }catch(Exception e){  

                                               e.printStackTrace();  

                                     }                                        

                                    try {  

                                              Thread.sleep(40);  

                                     } catch (InterruptedException e) {  

                                               e.printStackTrace();  

                                     }  

                            }  

                   }  

                    

        }  

   

} 

 

3.Activity

 

package com.android.ballmove;

import android.app.Activity;

import android.os.Bundle;

import android.util.DisplayMetrics;

import android.view.Window;

import android.view.WindowManager;

public class SportActivity extends Activity {

  public int screenWidth ;  

           public int screenHeight ;  

           BallSurfaceView bsv ;  

      /** Called when the activity is first created. */ 

      @Override 

      public void onCreate(Bundle savedInstanceState) {  

          super.onCreate(savedInstanceState);  

          bsv = new BallSurfaceView(this);  

         //获得屏幕尺寸  

         DisplayMetrics dm = new DisplayMetrics();  

      dm = this.getApplicationContext().getResources().getDisplayMetrics();  

               screenWidth = dm.widthPixels;  

                screenHeight = dm.heightPixels;  

             //下两句为设置全屏  

          requestWindowFeature(Window.FEATURE_NO_TITLE);  

                     getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN ,   

                                  WindowManager.LayoutParams.FLAG_FULLSCREEN);  

          

        setContentView(bsv);  

      }  

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2011-10-24 17:14发表