JDesktopPanel & JInternalFrame

[OmarMusallam]

i have hundreds of JInternalFrames control by JMenu and JdesktopPanel, each button add JInternalFrame to DesktopPanel, my problem is when i press the same button twice, it opens the same screen twice, how can i validate if the screen is alive before open it another time?

[ozzyman]

JInternalFrame has an isClosed() method to determine whether the frame has been close.

JInternalFrame (Java 2 Platform SE v1.4.2))

[OmarMusallam]

well, i tried it but let me show u part of the code :

private void jMenuItem1ActionPerformed(java.awt.event.ActionEve nt evt) {
JInternalFrameEx usrmain= new JInternalFrameEx();
jDesktopPane1.add(usrmain);
usrmain.setVisible(true);

}


this is the listener funtion, it creates new object of the frame then added to the desktoppane. so each time this function called , new instance of JInternalFrameEx will be created so when i validate isClose() . it will be pointing to the new instance , where the old instance still opened

i hope you got my point

[JosAH]

well, i tried it but let me show u part of the code :

private void jMenuItem1ActionPerformed(java.awt.event.ActionEve nt evt) {
JInternalFrameEx usrmain= new JInternalFrameEx();
jDesktopPane1.add(usrmain);
usrmain.setVisible(true);

}


this is the listener funtion, it creates new object of the frame then added to the desktoppane. so each time this function called , new instance of JInternalFrameEx will be created so when i validate isClose() . it will be pointing to the new instance , where the old instance still opened

i hope you got my point

Why not make that listener remember whether or not it created that JInternalFrame before? Something like this will do:

class YourListener implements ActionListener {
   private JInternalFrame usrmain; // remembers the JInternalFrame
   public void actionPerformed(ActionEvent ae) {
      if (usrmain == null) { // not yet created?
          usrmain= new JInternalFrameEx();
          jDesktopPane1.add(usrmain);
          usrmain.setVisible(true);
      }
   }
}

kind regards,

Jos