Help on closing the JOptionPane

[Rudy Yeung]

Grateful if someone can help me on this. I have written a Java program to pop up a dialog box. I cannot figure out how to handle the window closing event (pressing the X button on the top right corner). I read a Swing book, and it said that the function SetDefaultCloseOperation(JDialog.DISPOSE_ON_CLOSE) replaces the addWindowListener anonymous inner class for handling the closing event, but still it does not work. I have appended the java file:
import javax.swing.*;
public class DialogWindow {
private JFrame parent;
private JOptionPane optionPane;
private JDialog dialog;
public DialogWindow(JFrame parent) {
this.parent = parent;
initGUI();
initEventControl();
}
public void initGUI() {
optionPane = new JOptionPane("Confirm booking?",
JOptionPane.QUESTION_MESSAGE,
JOptionPane.YES_NO_OPTION);
dialog = optionPane.createDialog(parent,
"Booking Confirmation");
dialog.setVisible(true);
}
public void initEventControl() {
dialog.setDefaultCloseOperation(JDialog.DISPOSE_ON_CLOSE);
switch (((Integer)optionPane.getValue()).intValue())
{
case JOptionPane.YES_OPTION:
System.out.println("I have selected yes");
break;
case JOptionPane.NO_OPTION:
System.out.println("I have selected no");
break;
}
}
}

[Manfred Leonhardt]

Hi Rudy,
Stick with what works. Tried and true AWT events!
Before your call the setVisible method of dialog, do the following:

dialog.addWindowListener( new WindowAdapter()
                          {
                            public void windowClosing( WindowEvent e )
                            {
                              dispose();
                            }
                          }
                         );

This will work for sure no matter what any book says!
Regards,
Manfred.

[Rudy Yeung]

Despite adding your code, I still have difficulty enclosing the dialog window, and I still do not know the cause. There are a whole bunch of error messages complaining about the unknown source shown on the DOS shell upon closing the window like the following:
at javax.swing.AbstractButton.fireActionPerformed (Unknown Source)
at javax.swing.AbstractButton$ForwardActionEvents.actionPerformed (Unknown Source)
at javax.swing.DefaultButtonModel.fireActionPerformed (Unknown Source)
...
at java.awt.Component.processMouseEvent(Unknown Source)
...

[Manfred Leonhardt]

Hi Rudy,
I am running JDK1.2 under Win98SE and with just a little change to your code it seems to work good. I am not sure what you are trying to do, but here is the slight change I made to handle the x (close) window button:

  public void initEventControl() {
    dialog.setDefaultCloseOperation(JDialog.DISPOSE_ON_CLOSE);
    Integer intOb = (Integer)optionPane.getValue();
    if( intOb != null && intOb.intValue() == JOptionPane.YES_OPTION )
    {
      System.out.println("I have selected yes");
    }
    else
    {
      System.out.println("I have selected no");
    }
  }

The only problems that I encountered when user hits x was that the optionPane.getValue() was null and I got a NullPointerException. Once I placed the check in I got no errors.
P.S. Forget the stuff I said about WindowListener ... your stuff works just as well.
Manfred.
[This message has been edited by Manfred Leonhardt (edited February 04, 2001).]

[Rudy Yeung]

Manfred,
After changing the code a little bit according to your given snippet, my dialog window can now close properly. I do not realize that (Integer)optionPane.getValue() will return null if I choose the window closing option. Now, I learn one more thing. I really appreciate your help. Thank you.
Rudy

[Rudy Yeung]

Manfred,
BTW, do you know if there is any way I can pipe any runtime error message to a file? For the previous example, I think the Nullpointer exception message is at the very beginning, but I miss it because the DOS shell does not have a scroll bar to scroll up.