java-布局及补充组件

eg:
package com.chengzhi.pkg1;

import java.awt.CardLayout;
import java.awt.Color;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;

import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JPanel;

public class TestGui extends JFrame implements ActionListener{
    JPanel p1, p2, p3;
    JButton b1, b2;
    CardLayout cardlayout;
	public TestGui(){
		p1 = new JPanel();
		p2 = new JPanel();
		p3 = new JPanel();
		b1 = new JButton("显示红色按钮");
		b2 = new JButton("显示绿色按钮");
		cardlayout = new CardLayout();
		p1.setLayout(cardlayout);
		
		p2.setBackground(Color.red);
		p3.setBackground(Color.green);
		p1.add("panel2", p2);
		p1.add("panel3", p3);
		p2.add(b2);
		p3.add(b1);
		this.getContentPane().add(p1);
		this.setSize(300, 300);
		this.setVisible(true);
        this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);		
		//cardlayout.last(p1);
		//cardlayout.first(p1);
		//cardlayout.show(p1, "panel2");
		b1.addActionListener(this);
		b2.addActionListener(this);
		
		
	}
	public static void main(String[] args) {
		 new TestGui();
	}
	@Override
	public void actionPerformed(ActionEvent e) {
		 JButton b = (JButton)e.getSource();
		 if (b == b1){
			 //cardlayout.show(p1, "panel2");
			 cardlayout.next(p1);
		 }
		 if (b == b2)
		 {
			 //cardlayout.show(p1, "panel3");
			 cardlayout.next(p1);
		 }
	}

}