java cardlayoutÓ¦ÓÃ

import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
@SuppressWarnings("serial")
public class lab  extends JFrame{
 static Button [] b=new  Button[5];
 static JFrame f=new JFrame("lab");
 static JPanel  [] p=new JPanel[5];
 static JPanel  s=new JPanel();
 static JPanel t=new JPanel();
 static  CardLayout cl= new CardLayout();
 static class  ActionHandler implements ActionListener
 {
  
  int w;
  public ActionHandler(int i) {
   w=i;
  }
  public void actionPerformed(ActionEvent e) {
   
   cl.show(t, String.valueOf(w));
  }
  
 }
 public static void main(String[] args) 
 {
   
   s.setLayout(new GridLayout(1,5));
   
   
   
   for(int i=0;i<5;i++)
   {
    
     ActionListener a=new ActionHandler(i);
     b[i]=new Button("Button_"+(i+1));
     b[i].addActionListener(a);
     s.add(b[i]);
   }
   
   
   t.setLayout(cl);
   for(int i=0;i<5;i++)
   {
     p[i]=new JPanel();
     p[i].add(new  Label("this is the context of  Button"+(i+1)));
     Color c=new Color((int)(Math.random()*250),(int)(Math.random()*250),(int)(Math.random()*250));
     p[i].setBackground(c);    
     t.add(String.valueOf(i) ,p[i]);
   }
   
  
   f.add(s,BorderLayout.NORTH);
   f.add(t,Bor