如何在已实现的ActionListener中为JPanel添加显示/隐藏操作到JButton？

import javax.swing.*;
import java.awt.*;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;

public class PanelVisibilityExample {
    public static void main(String[] args) {
        JFrame frame = new JFrame("Panel Visibility Example");
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.setSize(300, 200);

        JPanel panel = new JPanel();
        panel.setBackground(Color.WHITE);
        panel.setVisible(false); // 初始状态为隐藏

        JButton button = new JButton("显示");
        button.addActionListener(new ActionListener() {
            boolean isPanelVisible = false; // 记录JPanel的显示状态

            @Override
            public void actionPerformed(ActionEvent e) {
                if (isPanelVisible) {
                    panel.setVisible(false);
                    button.setText("显示");
                } else {
                    panel.setVisible(true);
                    button.setText("隐藏");
                }
                isPanelVisible = !isPanelVisible; // 切换显示状态
            }
        });

        frame.getContentPane().setLayout(new BorderLayout());
        frame.getContentPane().add(panel, BorderLayout.CENTER);
        frame.getContentPane().add(button, BorderLayout.SOUTH);

        frame.setVisible(true);
    }
}