如何在CardLayout中显示不同的卡片？

• 我看不到Java7 show（容器父代，字符串名称）或Java6 show（容器父代，字符串名称）已过时

• 如果要看

  currentCard

  收益

  String

  从

  cl.show(cardPanel, "" + (currentCard));

编辑（我尝试了您的代码示例）

1.你忘了初始化最重要的变量

private CardLayout cardLayout = new CardLayout();

2.那么SSCCE可能是

import java.awt.*;import java.awt.event.ActionEvent;import java.awt.event.ActionListener;import javax.swing.*;public class CardLayoutTest extends Jframe {    private static final long serialVersionUID = 1L;    private JPanel cardPanel, jp1, jp2, buttonPanel;    private JLabel jl1, jl2;    private JButton btn1, btn2;    private CardLayout cardLayout = new CardLayout();    public CardLayoutTest() {        setTitle("Test med CardLayout");        setSize(400, 300);        cardPanel = new JPanel();        buttonPanel = new JPanel();        cardPanel.setLayout(cardLayout);        jp1 = new JPanel();        jp2 = new JPanel();        jl1 = new JLabel("Card 1");        jl2 = new JLabel("Card 2");        jp1.add(jl1);        jp2.add(jl2);        cardPanel.add(jp1, "1");        cardPanel.add(jp2, "2");        btn1 = new JButton("Show Card 1");        btn1.addActionListener(new ActionListener() { public void actionPerformed(ActionEvent e) {     cardLayout.show(cardPanel, "1"); }        });        btn2 = new JButton("Show Card 2");        btn2.addActionListener(new ActionListener() { public void actionPerformed(ActionEvent e) {     cardLayout.show(cardPanel, "2"); }        });        buttonPanel.add(btn1);        buttonPanel.add(btn2);        add(cardPanel, BorderLayout.NORTH);        add(buttonPanel, BorderLayout.SOUTH);    }    public static void main(String[] args) {        EventQueue.invokeLater(new Runnable() { @Override public void run() {     CardLayoutTest frame = new CardLayoutTest();     frame.setDefaultCloseOperation(Jframe.EXIT_ON_CLOSE);     frame.setVisible(true); }        });    }}