surface实例-小球弹起事例

ball.java

package com.example.sufacedemo;

import android.graphics.Bitmap;

import android.graphics.BitmapFactory;

import android.graphics.Canvas;

import android.graphics.Color;

import android.graphics.Paint;

import android.util.DisplayMetrics;

/**

 * 球类

 * @author zcl

 *

 */

public class Ball {

         /**

          * 球的高

          */

         public static final int HEIGHT = 93;

         /**

          * 球的宽

          */

         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();

         }

         /**

          * 运动

          */

         private void move() {

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

                            return;

                   }

                   if(upDirection){//向上

                            runY = runY + STEPLENGTH ;

                   }else{

                            runY = runY - STEPLENGTH ;

                   }

         }

         /**

          * 边界检测，使球不会飞出边界

          */

         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 ;

                   }

         }

}

BallSurfaceView

package com.example.sufacedemo;

import android.annotation.SuppressLint;

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);

	}

	@SuppressLint("WrongCall")

	@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.WHITE);// 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 {

		@SuppressLint("WrongCall")

		@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();

				}

			}

		}

	}

}

SportActivity.java

package com.example.sufacedemo;

import android.os.Bundle;

import android.app.Activity;

import android.view.Menu;

import android.app.Activity;

import android.content.pm.ActivityInfo;

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);

    }

}