在Java中使用卡片布局管理器的方法

import java.awt.BorderLayout;import java.awt.CardLayout;import java.awt.Color;import java.awt.Insets;import java.awt.event.ActionEvent;import java.awt.event.ActionListener;import javax.swing.JButton;import javax.swing.JFrame;import javax.swing.JLabel;import javax.swing.JPanel;import javax.swing.UIManager; public class TestMain extends JFrame {  private JPanel pane = null; // 主要的JPanel，该JPanel的布局管理将被设置成CardLayout  private JPanel p = null; // 放按钮的JPanel  private CardLayout card = null; // CardLayout布局管理器  private JButton button_1 = null; // 上一步  private JButton button_2 = null; // 下一步  private JButton b_1 = null, b_2 = null, b_3 = null; // 三个可直接翻转到JPanel组件的按钮  private JPanel p_1 = null, p_2 = null, p_3 = null; // 要切换的三个JPanel    public TestMain() {    super("CardLayout Test");    try {      // 将LookAndFeel设置成Windows样式      UIManager.setLookAndFeel("com.sun.java.swing.plaf.windows.WindowsLookAndFeel");    } catch (Exception ex) {      ex.printStackTrace();    }        card = new CardLayout(5, 5);    pane = new JPanel(card); // JPanel的布局管理将被设置成CardLayout    p = new JPanel(); // 构造放按钮的JPanel    button_1 = new JButton("< 上一步");    button_2 = new JButton("下一步 >");    b_1 = new JButton("1");    b_2 = new JButton("2");    b_3 = new JButton("3");    b_1.setMargin(new Insets(2,2,2,2));    b_2.setMargin(new Insets(2,2,2,2));    b_3.setMargin(new Insets(2,2,2,2));    p.add(button_1);    p.add(b_1);    p.add(b_2);    p.add(b_3);    p.add(button_2);    p_1 = new JPanel();    p_2 = new JPanel();    p_3 = new JPanel();    p_1.setBackground(Color.RED);    p_2.setBackground(Color.BLUE);    p_3.setBackground(Color.GREEN);    p_1.add(new JLabel("JPanel_1"));    p_2.add(new JLabel("JPanel_2"));    p_3.add(new JLabel("JPanel_3"));    pane.add(p_1, "p1");    pane.add(p_2, "p2");    pane.add(p_3, "p3");        button_1.addActionListener(new ActionListener(){ // 上一步的按钮动作      public void actionPerformed(ActionEvent e) {        card.previous(pane);      }    });    button_2.addActionListener(new ActionListener(){ // 下一步的按钮动作      public void actionPerformed(ActionEvent e) {        card.next(pane);      }    });    b_1.addActionListener(new ActionListener() { // 直接翻转到p_1      public void actionPerformed(ActionEvent e) {        card.show(pane, "p1");      }    });    b_2.addActionListener(new ActionListener() { // 直接翻转到p_2      public void actionPerformed(ActionEvent e) {        card.show(pane, "p2");      }    });    b_3.addActionListener(new ActionListener() { // 直接翻转到p_3      public void actionPerformed(ActionEvent e) {        card.show(pane, "p3");      }    });    this.getContentPane().add(pane);    this.getContentPane().add(p, BorderLayout.SOUTH);    this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);    this.setSize(300, 200);    this.setVisible(true);  }    public static void main(String[] args) {    new TestMain();  }  }