Eine Erklärung des Kartenlayout-Managers in Java

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();
    }
    /**创建一个具有指定的水平和垂直间隙的新卡片布局*/
    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");
    /**下面是翻转到卡片布局的某个组件，可参考API中的文档*/
    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();
  }
  
}