Re: JDialog Question...

From:

Ramon <ramif_47.invalid@yahoo.co.uk>

Newsgroups:

comp.lang.java.programmer

Date:

Tue, 01 Dec 2009 23:07:35 +0100

Message-ID:

<hf443a$3o2$1@news.eternal-september.org>

The following is a short version of my Jdialog...

public class InputDialog extends JDialog
{
     private Boolean okButtonPressed_; // true = OK button pressed

     /* init here ... */

     /*
      * OK button even handler
      */
     private void okButtonActionPerformed(java.awt.event.ActionEvent
evt)
     {
        this.setVisible(false);
        this.okButtonPressed_ = true;
     }
}

This is a method of the class which is calling my InputDialog:

     private void cmdUserSettings()
     {
         InputDialog inputDialog = new InputDialog(null, true);

         // if ok button was pressed
         if (inputDialog.getOkButtonPressed()) // #####
         { /* ... */ }
         else
         { /* ... */ }

         if (inputDialog != null)
             inputDialog.dispose();
     }

The line marked with ##### is sometimes throwing a NullPointerException,
thus indicating that somehow the garbage is destroying inputDialog...

Any suggestions?

Daniel Pitts wrote:

Ramon wrote:

Hi,

I'm trying to make a class that inherits from JDialog. The dialog has
two buttons: Ok and Cancel. When the OK button is clicked, the main
form is trying to read a result that is stored in the dialog's variable.

Question: Is there a safe way how to read a dialog's instance
variable (using a getter) after the dialog is set to invisible (i.e.
this.setVisible(false)) ?

PS: In general I am able to read the dialog's variables but,
apparently, sometimes the dialog is destroyed by the garbage collector...

Thanks.

If you have a reference to the JDialog, then it will not be garbage
collected. Are having a particular problem? What are the symptoms?

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