java 键盘监听

/**
 * 作者：@author ZhangShaoWen
 * 日期：2013-12-05
 * 功能：
 */
package com.test;

import javax.swing.*;
import java.awt.*;
import java.awt.event.*;

public class Demo1_3 extends JFrame{

    //定义变量
    Mypanel2 mp = null;

    public static void main(String[] args) {
        new Demo1_3();
    }

    //构造函数
    public Demo1_3(){

        mp = new Mypanel2();

        this.add(mp);
        this.addKeyListener(mp);//注册监听

        this.setSize(300,400);
        this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        this.setVisible(true);
    }
}

class Mypanel2 extends JPanel implements KeyListener{

    int x = 10;
    int y = 10;

    //重写paint方法
    public void paint(Graphics g){
        //必须调用父类的构造方法
        super.paint(g);
        g.setColor(Color.blue);
        g.fillOval(x, y, 10, 10);
    }

    //键的一个值被输出
    @Override
    public void keyTyped(KeyEvent e) {
        // TODO Auto-generated method stub

    }

    //按键的监听器
    @Override
    public void keyPressed(KeyEvent e) {
        // TODO Auto-generated method stub
        //System.out.println("键被按下"+e.getKeyChar());
        if(e.getKeyCode()==KeyEvent.VK_DOWN){//点击向下的键
            y++;
        }else if(e.getKeyCode()==KeyEvent.VK_UP){//点击向上的键
            y--;
        }else if(e.getKeyCode()==KeyEvent.VK_LEFT){//点击向左的键
            x--;
        }else if(e.getKeyCode()==KeyEvent.VK_RIGHT){//点击向右的键
            x++;
        }

        //调用repaint方法实现重画的功能
        this.repaint();
    }

    //释放键的监听器
    @Override
    public void keyReleased(KeyEvent e) {
        // TODO Auto-generated method stub

    }
}