Java SE (3) 之 事件监听

 package com.sun;
 import java.awt.*;
 import javax.swing.*;
 import java.awt.event.*;
 public class Demo_1_1 extends JFrame implements ActionListener{

     Mypanel mp;
     public static void main(String[] args) {
         // TODO Auto-generated method stub
         Demo_1_1  demo1 = new Demo_1_1();

     }
     public Demo_1_1() {
          mp = new Mypanel();
         JButton jb1 = new JButton("Button");
         JButton jb2 = new JButton("Button2");
         jb1.addActionListener(this);
         jb1.setActionCommand("kaishi");
         jb2.addActionListener(this);
         jb2.setActionCommand("jieshu");
         this.add(mp);
         this.add(jb1,BorderLayout.EAST);
         this.add(jb2,BorderLayout.NORTH);
         // TODO Auto-generated constructor stub
         this.setTitle("demo");
         this.setSize(300,300);
         this.setLocation(40, 40);
         this.setDefaultCloseOperation(EXIT_ON_CLOSE);
         this.setVisible(true);
     }
     public void actionPerformed(ActionEvent e) {
         // TODO Auto-generated method stub
         if(e.getActionCommand().equals("kaishi")){
               System.out.println("this is yes ");
               mp.setBackground(Color.BLUE);

         }else if(e.getActionCommand().equals("jieshu")) {
              System.out.println("this is no ");
              mp.setBackground(Color.BLACK);
         }
     }
 }
 class Mypanel extends JPanel{

     public void paint(Graphics g){
         super.paint(g);
             g.fillRect(0, 0, 300, 300);
             g.setColor(Color.YELLOW);
             g.fillRect(40, 40, 50, 50);
     }
 }