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