练习内容

• 小球运动代码练习5遍
• scan 第一章文字内容

感想

• 抄了4遍就可以默写了
• 默写出来就可以不用抄了

附件

import java.awt.*;
public class MyBall{
    public static void main(String args[]) {
        Frame w = new Frame();
        w.setSize(300,400);
        
        MyPanel mp = new MyPanel();
        
        w.add(mp);
        
        Thread t = new Thread(mp);
        t.start();
        
        w.show();
    }
}

class MyPanel extends Panel implements Runnable{
    
    int x = 30;
    int y = 30;
    int att = 0;
    
    public void paint(Graphics g) {
        g.fillOval(x,y,30,30);
    }
    
    public void run() {
        while(true) {
            //定义飞行姿态
            if (att == 0) {
                x++;
                y++;
            }
            
            if (att == 1) {
                x--;
                y++;
            }
            
            if (att == 2) {
                x--;
                y--;
            }
            
            if (att == 3) {
                x++;
                y--;
            }
            
            //定义飞行策略
            
            if(x > 263) {
                if (att == 0) {
                    att = 1;
                } else {
                    att = 2;
                }
            }
            
            if ( y > 341) {
                if (att == 1) {
                    att = 2;
                }else {
                    att = 3;
                }
            }
            
            if ( x < 0) {
                if (att == 2) {
                    att = 3;
                }else {
                    att = 0;
                }
            }
            
            if( y < 0) {
                if(att == 3) {
                    att = 0;
                }else {
                    att = 1;
                }
            }
            
            try {
                Thread.sleep(3);
            }catch(Exception e) {}
            repaint();
        }
    }
}