Java基础（三）：桌球案例

桌球案例

图片资源：

代码

package com.bjsxt;
import java.awt.*;
import javax.swing.*;

import static com.sun.glass.ui.Cursor.setVisible;


public class BallGame extends JFrame {

    Image ball = Toolkit.getDefaultToolkit().getImage("../../images/ball.png");
    Image desk = Toolkit.getDefaultToolkit().getImage("../../images/desk.jpg");

    double x = 200;
    double y = 200;

    double degree = 3.14 / 3; // 弧度  3.14 = 180°    60°

    // 绘制窗口
    public void paint(Graphics g) {
        System.out.println("窗口被画一次");
        g.drawImage(desk, (int)0, (int)0, null);
        g.drawImage(ball, (int)x, (int)y, null);

        x = x + 10*Math.cos(degree);
        y = y + 10*Math.sin(degree);

        if (y > 501 - 40 - 50 || y < 40){
            degree =  - degree;
        }

        // 碰到左右边界
        if(x > 856 - 40 - 50 || x < 40){
            degree = 3.14 - degree;
        }
    }

    void launchFrame(){
        setSize(856, 501);
        setLocation(100, 100);
        setVisible(true);

        while(true){
            repaint();

            try{
                Thread.sleep(40);  // 1s = 1000ms; 大约1秒绘制1000/40=25次
            } catch(InterruptedException e){
                e.printStackTrace();
            }
        }
    }

    public static void main(String[] args) {
        System.out.println("我的小游戏开始啦");

        BallGame game = new BallGame();
        game.launchFrame();
    }
}