如何根据 Java 中的组合框选择动态更改 UI 元素？

<code class="java">import java.awt.BorderLayout;
import java.awt.CardLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.JComboBox;
import javax.swing.JFrame;
import javax.swing.JPanel;

public class CardPanelExample {

    public static void main(String[] args) {
        JFrame frame = new JFrame();

        // Create a CardLayout to manage the layers
        CardLayout layout = new CardLayout();
        JPanel cards = new JPanel(layout);

        // Add the two layers of controls to the CardLayout
        JPanel layer1 = new JPanel();
        layer1.add(new JLabel("Layer 1"));

        JPanel layer2 = new JPanel();
        layer2.add(new JLabel("Layer 2"));

        cards.add(layer1, "layer1");
        cards.add(layer2, "layer2");

        // Create a combo box and add it to the GUI
        JComboBox<String> combo = new JComboBox<>();
        combo.addItem("Layer 1");
        combo.addItem("Layer 2");

        // Add an ActionListener to the combo box
        combo.addActionListener(new ActionListener() {
            @Override
            public void actionPerformed(ActionEvent e) {
                // Show the appropriate card based on the selected item
                layout.show(cards, combo.getSelectedItem());
            }
        });

        // Add the combo box and cards panel to the GUI
        frame.add(combo, BorderLayout.NORTH);
        frame.add(cards, BorderLayout.CENTER);
</code>