Android游戏开发：物理游戏之重力系统开发--圆形自由落体Demo

    本节为大家提供有关物理游戏的知识，讲解了一个简单的圆形自由落体Demo的编写。。

Java代码

package com.himi;

import java.util.Random;

import java.util.Vector;

import android.content.Context;

import android.graphics.Canvas;

import android.graphics.Color;

import android.graphics.Paint;

import android.util.Log;

import android.view.KeyEvent;

import android.view.SurfaceHolder;

import android.view.SurfaceView;

import android.view.SurfaceHolder.Callback;

public class MySurfaceViee extends SurfaceView implements Callback, Runnable {

    private Thread th;

    private SurfaceHolder sfh;

    private Canvas canvas;

    private Paint paint;

    private boolean flag;

    public static int screenW, screenH;

    private Vector<MyArc> vc;//这里定义装我们自定义圆形的容器

    private Random ran;//随即库

    public MySurfaceViee(Context context) {

        super(context);

        this.setKeepScreenOn(true);

        vc = new Vector<MyArc>();

        ran = new Random();//备注1

        sfh = this.getHolder();

        sfh.addCallback(this);

        paint = new Paint();

        paint.setAntiAlias(true);

        setFocusable(true);

    }

    public void surfaceCreated(SurfaceHolder holder) {

        flag = true;//这里都是上一篇刚讲过的。。。

        th = new Thread(this);

        screenW = this.getWidth();

        screenH = this.getHeight();

        th.start();

    }

    public void draw() {

        try {

            canvas = sfh.lockCanvas();

            canvas.drawColor(Color.BLACK);

            if (vc != null) {//当容器不为空，遍历容器中所有圆形画方法

                for (int i = 0; i < vc.size(); i++) {

                    vc.elementAt(i).drawMyArc(canvas, paint);

                }

            }

        } catch (Exception e) {

            // TODO: handle exception

        } finally {

            try {

                if (canvas != null)

                    sfh.unlockCanvasAndPost(canvas);

            } catch (Exception e2) {

            }

        }

    }

    private void logic() {//主逻辑

        if (vc != null) {//当容器不为空，遍历容器中所有圆形逻辑

            for (int i = 0; i < vc.size(); i++) {

                vc.elementAt(i).logic();

            }

        }

    }

    @Override

    public boolean onKeyDown(int keyCode, KeyEvent event) {

        //当按键事件响应，我们往容器中仍个我们的圆形实例

        vc.addElement(new MyArc(ran.nextInt(this.getWidth()), ran.nextInt(100), ran.nextInt(50)));

        return true;

    }

    public void run() {

        // TODO Auto-generated method stub

        while (flag) {

            logic();

            draw();

            try {

                Thread.sleep(100);

            } catch (Exception ex) {

            }

        }

    }

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

        Log.v("Himi", "surfaceChanged");

    }

    public void surfaceDestroyed(SurfaceHolder holder) {

        flag = false;

    }

}

       OK，代码都很简单，也很清晰！ 稍微说一句：像MyArc里面也有类似MysurfaceView中一样的方法 logic() 以及draw()，这样能更好的管理我们的代码结构，思路清晰，各尽其责，避免混乱。

Android游戏开发：物理游戏之重力系统开发--圆形自由落体Demo