java通过方向键控制小球移动的小游戏

public class BallMove extends JFrame

class MyPanel extends JPanel

int x = 10;
int y = 10;
    @Override
    public void paint(Graphics g) {
        super.paint(g);
        g.fillOval(x,y,20,20);
    }

MyPanel myPanel = null;
 myPanel = new MyPanel();//面板

this.add(myPanel);

this.setSize(400,300);

this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

this.setVisible(true);

class MyPanel extends JPanel implements KeyListener

public void keyPressed(KeyEvent e)

if(e.getKeyCode()==KeyEvent.VK_DOWN){//向下的键
            y++;
        }
        //让面板重绘
 
         else if(e.getKeyCode()==KeyEvent.VK_UP){//向下的键
            y--;
        }
        //让面板重绘
 
      else if(e.getKeyCode()==KeyEvent.VK_LEFT){//向下的键
            x--;
        }
      else if(e.getKeyCode()==KeyEvent.VK_RIGHT){
          x++;
        }

this.repaint();

import javax.swing.*;
import java.awt.*;
import java.awt.event.KeyEvent;
import java.awt.event.KeyListener;
 
/**
 * @author shijiu
 */
//演示小球通过键盘控制上下左右的移动》java事件控制
public class BallMove extends JFrame{//框架
    MyPanel myPanel = null;
    public static void main(String[] args) {
        BallMove ballMove = new BallMove();
    }
    public BallMove(){
        myPanel = new MyPanel();//面板
        this.add(myPanel);
        this.setSize(400,300);
        this.addKeyListener(myPanel);
        this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        this.setVisible(true);
    }
}
//KeyListener 是监听器  可以监听键盘事件
class MyPanel extends JPanel implements KeyListener {
   //为了小球可以移动 赋个变量
    int x = 10;
    int y = 10;
    @Override
    public void paint(Graphics g) {
        super.paint(g);
        g.fillOval(x,y,20,20);
    }
 
        //有字符输出时 该方法就会触发
    @Override
    public void keyTyped(KeyEvent e) {
 
    }
 
    //当某个键按下时 该方法会触发
    @Override
    public void keyPressed(KeyEvent e) {
        System.out.println((char)e.getKeyCode()+"被按下去");
        //根据用户按下的不同键  来处理小球的移动（上下左右）
        //在java中 会给每一个键 分配一个值
        if(e.getKeyCode()==KeyEvent.VK_DOWN){//向下的键
            y++;
        }
        //让面板重绘
 
         else if(e.getKeyCode()==KeyEvent.VK_UP){//向下的键
            y--;
        }
        //让面板重绘
 
      else if(e.getKeyCode()==KeyEvent.VK_LEFT){//向下的键
            x--;
        }
      else if(e.getKeyCode()==KeyEvent.VK_RIGHT){
          x++;
        }
        //让面板重绘
        this.repaint();
    }
 
    //当某个键释放了（松开） 该方法会触发
    @Override
    public void keyReleased(KeyEvent e) {
 
    }
}