🚀 go-pugleaf

Hello,

Does someone know how I can get a notification when a
JComponent(JPanel/Button etc), become visible or hide? I used a
ComponentListener but that's not working. The example below,
generate only a resize ComponentEvent(because of the LayoutManager).

If this is a bug: how can I work arround this bug on a easy way: getting a
notification when a component become visible or hide.

If this is not a bug: what I am doing wrong?

Thanks!

Jos

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

public class Test  extends JFrame
{
  public static void main(String[] args)
  {
     Test test=new Test();
     test.setVisible(true);
  }

  public Test()
  {
    setBounds(10,10,300,300);
//    setLayout(null); // without setLayout(null) -> resized componentEvent
    JPanel panel=new JPanel();
    panel.setBackground(Color.blue);
    getContentPane().add(panel);
    panel.addComponentListener(new PanelListener());
  }

   class PanelListener implements ComponentListener
   {
     public void componentShown(ComponentEvent e)
     {
      System.out.println("Panel shown");
     }
     public void componentHidden(ComponentEvent e)
     {
      System.out.println("Panel hidden");
     }
     public void componentResized(ComponentEvent e)
     {
      System.out.println("Panel resized");
     }
     public void componentMoved(ComponentEvent e)
     {
      System.out.println("Panel moved");
     }

   }
}