CardLayout中的交换卡问题

Question

我正在尝试使用NetBeans IDE 8.2从头开始编写GUI。我决定将我的RPG游戏基于Card Layout。因此，布局从卡“信息窗格”开始，我可以在第一个开关上更改面板，但是我不太确定如何让它们交换回来。我让程序在控制台上打印了一个字符串，以便确保卡切换正确。

package guigamefromscratch;
import javax.swing.*;
import java.awt.*;
import java.awt.event.*;
public class GUIGameFromScratch implements ItemListener{
    static String[] Classes = {
            "Barbarian",
            "Fighter",
            "Rogue",
            "Wizard"
        };
    static String[] Races = {
            "Dwarf",
            "Gnome",
            "Half-Orc",
            "Human"
        };
    static String[] Gender = {
            "Male",
            "Female"
        };
    static String cls;
    static String rcs;
    static String gen;
    static String gameName = "RPG Text";
    static Component frame = null;
    static Component icon = null;
    static JPanel cards;
    static GUIGameFromScratch work = new GUIGameFromScratch();
    static JPanel card1;

public static void main(String[] args) {
    Classes(Classes);
    Races(Races);
    Gender(Gender);
    work.Run();
}

public static void Classes(String[] Classes){
    cls = (String)JOptionPane.showInputDialog(frame,
            "Choose a Class:",
            gameName,
            JOptionPane.PLAIN_MESSAGE, (Icon) icon,
            Classes,
            Classes[0]
    );
}

public static void Races(String[] Races){
    rcs = (String)JOptionPane.showInputDialog(frame,
            "Choose a Race:",
            gameName,
            JOptionPane.PLAIN_MESSAGE, (Icon) icon,
            Races,
            Races[0]
    );
}

public static void Gender(String[] Gender){
    gen = (String)JOptionPane.showInputDialog(frame,
            "Choose a Gender:",
            gameName,
            JOptionPane.PLAIN_MESSAGE, (Icon) icon,
            Gender,
            Gender[0]
    );
}

public void Run(){
    JFrame display = new JFrame();
    display.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    display.pack();
    display.setSize(300,250);
    display.setTitle(gameName);
    display.setVisible(true);
    display.setResizable(false);
    JPanel comboBoxPane = new JPanel();
    String[] comboBoxItems = {"Info Pane", "Game Pane"};
    JComboBox cb = new JComboBox(comboBoxItems);
    cb.setEditable(false);
    cb.addItemListener(this);
    comboBoxPane.add(cb);
    card1 = new JPanel();
    card1.add(new JLabel("Class: " + cls));
    card1.add(new JLabel("Race: " + rcs));
    card1.add(new JLabel("Gender: " + gen));
    cards = new JPanel(new CardLayout());
    cards.add(card1, comboBoxItems[0]);
    display.add(comboBoxPane, BorderLayout.PAGE_START);
    display.add(cards, BorderLayout.CENTER);
    comboBoxPane.setVisible(true);
    cards.setVisible(true);
    card1.setVisible(true);
}

@Override
public void itemStateChanged(ItemEvent e) {
    if (e.getStateChange() == ItemEvent.SELECTED){
        cards.setVisible(false);
        card1.setVisible(false);
        System.out.println("This is America");
        cards.revalidate();
        card1.revalidate();
        cards.repaint();
        card1.repaint();
    }
    else {
        cards.setVisible(true);
        card1.setVisible(true);
    }
}
}

如果有人有任何帮助，我将不胜感激。