java的CardLayout[Java编程]

//: CardLayout1.java
// Demonstrating the CardLayout
import java.awt.*;
import java.applet.Applet;

class ButtonPanel extends Panel {
  ButtonPanel(String id) {
    setLayout(new BorderLayout());
    add("Center", new Button(id));
  }
}

public class CardLayout1 extends Applet {
  Button
    first = new Button("First"),
    second = new Button("Second"),
    third = new Button("Third");
  Panel cards = new Panel();
  CardLayout cl = new CardLayout();
  public void init() {
    setLayout(new BorderLayout());
    Panel p = new Panel();
    p.setLayout(new FlowLayout());
    p.add(first);
    p.add(second);
    p.add(third);
    add("North", p);
    cards.setLayout(cl);
    cards.add("First card", 
      new ButtonPanel("The first one"));
    cards.add("Second card", 
      new ButtonPanel("The second one"));
    cards.add("Third card", 
      new ButtonPanel("The third one"));
    add("Center", cards);
  }
  public boolean action(Event evt, Object arg) {
    if (evt.target.equals(first)) {
      cl.first(cards);
    } 
    else if (evt.target.equals(second)) {
      cl.first(cards);
      cl.next(cards);
    } 
    else if (evt.target.equals(third)) {
      cl.last(cards);
    } 
    else 
      return super.action(evt, arg);
    return true;
  }
} ///:~