键盘监听事件

/**

 * 功能：加深对事件处理机制的理解

 * 1.通过上下左右键，来来控制一个小球的位置

 */

package 时间处理;

import java.awt.*;

import javax.swing.*;

import java.awt.event.*;

 

public class Test2 extends JFrame{

 

    MyPanel mp=null;

   

    public static void main(String[] args) {

       // TODO Auto-generated method stub

       Test2 test2=new Test2();

    }

   

    //构造函数

    public Test2()

    {

       mp=new MyPanel();

       this.add(mp);

      

       this.addKeyListener(mp);

      

       this.addKeyListener(mp);

       this.setSize(400,300);

       this.setVisible(true);

       this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

      

    }

 

}

 

//定义自己的面板

class MyPanel extends JPanel implements KeyListener

{

    int x=10;

    int y=10;

    public void paint(Graphics g)

    {

       super.paint(g);

      

       g.fillOval(x, y, 10, 10);

    }

 

    //键被按下

    public void keyPressed(KeyEvent e) {

       // TODO Auto-generated method stub

       //System.out.println(" 键被按下"+(char)e.getKeyChar());

 

       if(e.getKeyCode()==KeyEvent.VK_DOWN)

       {

           y++;

       }

       else if (e.getKeyCode()==KeyEvent.VK_UP)

       {

           y--;

       }

       else  if (e.getKeyCode()==KeyEvent.VK_LEFT)

       {

           x--;

       }

       else if(e.getKeyCode()==KeyEvent.VK_RIGHT)

       {

           x++;

       }

       //调用repaint函数，来从新绘制界面

       this.repaint();

    }

 

    //键被释放

    public void keyReleased(KeyEvent e) {

       // TODO Auto-generated method stub

      

    }

 

    //键的一个值被输出

    public void keyTyped(KeyEvent e) {

       // TODO Auto-generated method stub

      

    }

}