Calling a JDialog in the windowClosing Event of a JFrame

Question

hi
As we had seen in many applications when u try to close the application a Dialog box will appear and it will ask whether we have to save it.I want to implement the same thing in my windowClosing Event of the Frame.I tried doing this by calling the Dialog i have created by using the show method in the window closing event of the Frame,but what happens is when i close the frame the Dialog box flickers and disappears.What should i do to avoid this flickering and Disppearing of the Dialog box.I want the Dialog box to stay on the screen.What should i do? any ideas?
thanks

Answer 1

import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
public class WindowClosingTest extends JFrame {
     public WindowClosingTest() {
          try {
               setDefaultCloseOperation(JFrame.DO_NOTHING_ON_CLOSE);
               JButton button = new JButton("Close");
               button.addActionListener(new ActionListener() {
                    public void actionPerformed(ActionEvent ae) { performClose(); }
               addWindowListener(new WindowAdapter() {
                    public void windowClosing(WindowEvent we) { performClose(); }
               getContentPane().add(button);
               pack();
               setLocationRelativeTo(null);
               setVisible(true);
          } catch (Exception e) { e.printStackTrace(); }
     private void performClose() {
          int n = JOptionPane.showConfirmDialog(null, "Close?", "Confirm", JOptionPane.YES_NO_OPTION);
          if (n != 1) { System.exit(0); }
     public static void main(String[] args) { new WindowClosingTest(); }
}