Java_太阳系_行星模型_小游戏练习_详细注释

//实现MyFrame--实现绘制窗口，和实现重写 重画窗口线程类

package cn.xiaocangtian.Test;

import java.awt.Frame;
import java.awt.event.WindowAdapter;
import java.awt.event.WindowEvent;


public class MyFrame extends Frame {

        //加载窗口
        public void launchFrame() {
            setSize(Constant.GAME_WIDTH, Constant.GAME_HEIGHT);       //设置窗口大小
            setLocation(100, 100);   //设置左上角坐标，开始位置, 也就是窗口开始位置
            setVisible(true);        //设置为可见(默认为不可见)
            
            //启动重画线程
            new PaintThread().start();
            
            //匿名内部类---用来关闭窗口
            addWindowListener(new WindowAdapter() {
                @Override
                public void windowClosing(WindowEvent e) {
                    System.exit(0);
                }
            });
            
        }
        
        /**
         * 定义一个重画窗口的线程类
         * 是一个内部类(方便访问外部类属性)
         */
        class PaintThread extends Thread {
            public void run() {
                while (true) {
                    repaint();             //重画
                    try {
                        Thread.sleep(40);  //1s = 1000ms
                    } catch (InterruptedException e) {
                        e.printStackTrace();
                    }  
                }
            }
        }
        
}

package cn.xiaocangtian.Util;

import java.awt.Image;
import java.awt.Toolkit;
import java.awt.image.BufferedImage;
import java.io.IOException;
import java.net.URL;

import javax.imageio.ImageIO;
import javax.swing.ImageIcon;

/**
 * 游戏开发中常用的工具类(比如:加载图片等方法)
 * @author admin
 *
 */
public class GameUtil {
    
    private GameUtil () {} //工具类通常将构造方法私有
    
    public static Image getImage(String path) {
//        URL u = GameUtil.class.getClassLoader().getResource(path);
//        BufferedImage img = null;
//        try {
//            img = ImageIO.read(u);
//        } catch (IOException e) {
//            e.printStackTrace();
//        }
//        
//        return img;  //BufferedImage是Image子类，也算正确返回
        return Toolkit.getDefaultToolkit().getImage(GameUtil.class.getClassLoader().getResource(path));
    }
}

package cn.xiaocangtian.Solar;

import java.awt.Graphics;
import java.awt.Image;

import cn.xiaocangtian.Util.GameUtil;

//封装成类
//导入图片
public class Star {
    Image img;                //用于导入图片
    double x, y;              //图片位置
    int width, height;        //图片长宽
    
    public void draw(Graphics g) {
        g.drawImage(img, (int)x, (int)y, null);
    }
    
    public Star() {          //子类要调用父类的默认造函数
        
    }
    
    public Star(Image img) {
        this.img = img;
        this.width = img.getWidth(null);
        this.height = img.getHeight(null);
        
    }
    
    public Star(Image img, double x, double y) {
        this(img);
        this.x = x;
        this.y = y;
        
    }
    
    //导入
    public Star(String imgpath, double x, double y) {
        this(GameUtil.getImage(imgpath), x, y);
    }
}

package cn.xiaocangtian.Util;

/**
 * 游戏项目中用到的常量
 * 单独负责常量
 * @author admin
 */
public class Constant {
    
    public static final int GAME_WIDTH = 750;
    public static final int GAME_HEIGHT = 600;
    
}

package cn.xiaocangtian.Solar;

import java.awt.Color;
import java.awt.Graphics;
import java.awt.Image;

import cn.xiaocangtian.Util.GameUtil;

public class Planet extends Star {
    
    //除了图片，坐标，行星沿着某个椭圆运行：长轴，短轴，速度， 角度，绕着某个Star飞
    double longAxis;        //椭圆的长轴
    double shortAxis;       //椭圆的短轴
    double speed;           //飞行的速度
    double degree;          //角度
    Star center;            //中心
    boolean satillite;      //标志是否是卫星
    
    public void draw(Graphics g) {
        super.draw(g);
        move();
        if (!satillite) {   //不是卫星再画出轨迹
            drawTrace(g);
        }
    }
    
    public void move() {
        //沿着椭圆飞
        x = (center.x + center.width/2) + longAxis * Math.cos(degree);
        y = (center.y + center.height/2) + shortAxis * Math.sin(degree);                
        //速度不一样，所以增量也不同
        degree += speed;
    }
    
    //画出行星的轨迹
    public void drawTrace(Graphics g) {
        double ovalX, ovalY, ovalWidth, ovalHeight;
        ovalHeight = longAxis * 2;                         //长度即为长轴*2
        ovalWidth = shortAxis * 2;
        ovalX = (center.x + center.width/2) - longAxis;    //左上顶点为(中心.x + x.width/2) - 长轴
        ovalY = (center.y + center.height/2) - shortAxis;
        
        Color oldColor = g.getColor();
        g.setColor(Color.blue);                            //设置轨迹颜色
        g.drawOval((int)ovalX, (int)ovalY, (int)ovalHeight, (int)ovalWidth);
        g.setColor(oldColor);
    }
    
    
    //需要调用父类的空构造器
    public Planet(Star center, String imgpath, double longAxis,
            double shortAxis, double speed) {
        super(GameUtil.getImage(imgpath));
        
        this.center = center;
        this.x = center.x + longAxis;         //行星的位置
        this.y = center.y;
        
        this.longAxis = longAxis;             //当前行星的长轴
        this.shortAxis = shortAxis;
        this.speed = speed;
        
        this.width = img.getWidth(null);
        this.height = img.getHeight(null);
    }

    public Planet(Star center, String imgpath, double longAxis,
            double shortAxis, double speed, boolean satellite) {
        this(center, imgpath, longAxis, shortAxis, speed);
        this.satillite = satellite;
    }
    
    public Planet(Image img, double x, double y) {
        super(img, x, y);
    }
    
    public Planet(String imgpath, double x, double y) {
        super(imgpath, x, y);
    }
    
}

package cn.xiaocangtian.Solar;

import java.awt.Graphics;
import java.awt.Image;

import cn.xiaocangtian.Util.Constant;
import cn.xiaocangtian.Util.GameUtil;
import cn.xiaocangtian.Util.MyFrame;

/**
 * 太阳系主窗口
 * @author admin
 *
 */
public class SolarFrame extends MyFrame {
    //导入背景
    Image bg = GameUtil.getImage("images/yuzhou.png");
    //这里是利用封装的类，导入图片
    Star sun = new Star("images/sun.png", Constant.GAME_WIDTH / 2, Constant.GAME_HEIGHT / 2);
    Planet earth = new Planet(sun, "images/polar.png", 150, 100, 0.1);
    Planet moon = new Planet(earth, "images/moon.png", 30, 20, 0.3, true);
    Planet Mars = new Planet(sun, "images/Mars.png", 200, 130, 0.2);
    
    /**
     * 可以继续添加 其他 行星，只需一行代码(已经封装好)
     * ......
     * ......
     * ......
     */
    
    /**
     * 重写重绘函数，此为回调函数，只需要实现，然后由系统自动调用
     */
    public void paint(Graphics g) {
        g.drawImage(bg, 0, 0, null);
        sun.draw(g);       //这里使用的是封装的方法
        earth.draw(g);
        moon.draw(g);
        Mars.draw(g);
        
        /***
         * 还可以继续添加其他行星并绘制
         * ..........
         * ..........
         * ..........
         */
    }
    
    public static void main(String[] args) {
        new SolarFrame().launchFrame();
    }
}

//本程序只添加了太阳，地球，月球，火星，其余可以自行添加，使用封装好的方法，只用十分简洁的代码即可