Modal JWindow

[Barry Andrews]

Hi All,
Does anyone know if it is possible to force a JWindow to be modal? I have created a custom Dialog box using JWindow that stores user input from a field into a variable. I am calling this dialog from another application like this:
MyEnterDialog ed = new MyEnterDialog();
ed.show();
String theString = ed.getUserString();
The problem is that I now realize that JWindow is not modal, so when I call show(), the program continues to execute so that getUserString() is returning null because it has not been set by the user yet.
I know that I could extend JDialog instead of JWindow, but I am looking to do away with the title bar on the window if it is possible. Thanks very much for your help!!!

Barry

[Barry Andrews]

I just found the solution to my problem in case anyone is interested. All I have to do is override the show() method. In the show() method I can call setVisible() and then create an endless loop with while(true). The loop will break only when a boolean is true which will happen when the user presses a button. This will force the other window to wait until someone has pressed a button to execute the next line of code. I believe this will work. Does anyone else have a better idea?
Thanks,
Barry

[Cindy Glass]

Clever!!

[Barry Andrews]

Thanks Cindy, but now I have run into another problem. First of all, I cannot override the show() method like I wanted to because for some reason my setVisible() method gets called many many times and Java does not like that. So, I created another method called hold() and put the while(true) loop inside that. The problem is that my dialog box never gets finished painting because when the hold() method is entered the CPU gets 'frozen.' I have also tried multi-threading, but cannot seem to get that to work either. Do you have any suggestions?
Thanks!!

Barry

[Cindy Glass]

Just use a JDialog with no title -
JDialog(Frame owner, boolean modal)
Creates a modal or non-modal dialog without a title and with the specified owner Frame.

[Barry Andrews]

Yes, but I want no title bar at all. You can have no title, but the bar will still be there.

Thanks,
Barry

[Dave Turner]

hi,
i think there may be a way to do what you want by synchronizing on the JWindow once it has been created, then calling wait() on it. The running thread will now wait indefinitely until it is notified to resume running. To start it running again the JWindow must be synchronized on again and notify() then called on it.

// In the class that creates the JWindow
...
MyEnterDialog med = new MyEnterDialog(...);
med.show();
synchronized( med )
{
   med.wait(); // Thread waits here until told to resume
}
String s = med.getUserString(); // get the String from the JWindow
...
// And in the MyJWindow
// when the 'ok' button is clicked
// the actionlistener performs the
// following function calls
...
myEnterDialogRef.setVisible( false );
synchronized( myEnterDialogRef )
{
   myEnterDialogRef.notify(); //notify the waiting Thread
}
...

hope this helps,
Dave

[chakri s]

Hi Dave,

I tried this thread synchronize and the JWindow i was trying show is not painted. It shows a unpainted JWindow which is white. Can you tell me what this could mean ??

[Michael Dunn]

(replying to recent post, not those in 2001!)

seems easier to use an undecorated modal JDialog

something like this

    
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
 
class MainFrame
{
  public void buildGUI()
  {
    final JDialog d = new JDialog();
    JButton btn = new JButton("Close");
    d.getContentPane().add(btn,BorderLayout.SOUTH);
    d.setUndecorated(true);
    d.setModal(true);
    d.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    d.setSize(300,200);
    d.setLocationRelativeTo(null);
    btn.addActionListener(new ActionListener(){
      public void actionPerformed(ActionEvent e)
      {
        d.dispose();
      }
    });
    d.setVisible(true);
    System.out.println("Should only see this after dialog closes");
    System.exit(0);
  }
  public static void main(String[] args){new MainFrame().buildGUI();}
}