How to make a modal frame?

Question

Hello!
My problem is quite simple, but I don't know how to make some MODAL frames (JFrame I mean). In my application, the user can open a same frame even if this frame is already opened and that's not really good.
So, I want the user to close the frame before opening another one.
Can anyone explain me how to do that?

Answer 1

Generally your actionListener will be an internal class of your main frame class. Usually an anonymous internal class. That means it can act on variables in the frame (which is the sensible place to keep the flags).
Something like:
class Class1 extends JDesktop {
boolean itsOpen = false;
openAction.setActionListener(new ActionListener(){
  public void actionPerformed(ActionEvent e) {
    if(!itsOpen) {
       itsOpen = true;
       openAction.setEnabled(false);
       MyInternalFrame newFrame = new MyInternalFrame(Class1.this, ....);
       add(newFrame);
   });You do need some way for the internal frame to act on the variables in the main frame. There are various ways of achieving this.
If we're dealing with a genuine InternalFrame there's a special InternalFrameListener (?) which allows your main frame to listen for the window closing. You can use this instead of hacking the dispose method.
If you're main frame is a JDeskTop then you can use getDesktop() in your internal frame to access it, then cast the result to the real class of your desktop.
Our you can simply add a pointer to your class1 to the contructor of your internal frame class.
You could even get clever and create your own listener system.