显示JPanel时的火灾事件

每当显示扩展JPanel(MyPanel)时,我都希望得到通知。

import java.awt.*;
//import java.awt.event.*;
import javax.swing.*;

public class FireOnShown extends JFrame {
  public static final long serialVersionUID = 100L;

  public FireOnShown() {
    setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    setSize(320, 240);
    setLocation(800, 40);
    add(new MyPanel("Hello"));
    setVisible(true);
  }


  static public void main(String args[]) {
    EventQueue.invokeLater(FireOnShown::new);
  }

}

我尝试应用ComponentListener或重写setVisible(…),但都不起作用。

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

class MyPanel extends JPanel {
  public static final long serialVersionUID = 50247L;

  public MyPanel(String labelTxt) {
    setPreferredSize(new Dimension(300, 40));
    add(new JLabel(labelTxt));
    addComponentListener(new ComponentListener() {
      public void componentHidden(ComponentEvent e) {
      }
      public void componentMoved(ComponentEvent e) {
      }
      public void componentResized(ComponentEvent e) {
      }
      public void componentShown(ComponentEvent e) {
    System.out.println("componentShown");
      }
    });
  }


  @Override
  public void setVisible(boolean flag) {
    System.out.println("Visible "+flag);
    super.setVisible(flag);
  }

}

还有[java教程]中的示例( https://docs.oracle.com/javase/tutorial/uiswing/events/componentlistener.html )不会开火 componentShown 当显示其面板时。还有其他办法吗?