Hi all,

While I'm trying to understand the concepts of OO programming (in
Java),
I need to disable some MenuItems and enable them when some action is
performed (in this case clicking on the MenuItem "Lees Breuken").
The disabling of MenuItems is succeeded, but Enabling them is not easy
though.

How can I, for one, enable the button (miSortUp)?

Oh.. and I keep getting this message
"local variable miSortUp is accessed from within inner class; needs to
be
declared final"
but when I declare this variable final (final
miSortUp.setEnabled(true);) I get a message "<identifier> excepted";
why?

Here follows my code..

Thanks!

------------------------------------------------------------------------------

public class RationaalCalculator extends Panel
{
 private RationaalView op1rv, op2rv, resrv;
 private RationaalInvoer ri;
 private Container toetsenpaneel;

 ... (IRRELEVANT CODE) ...


 public void addMenuBar() {
   // trucje voor menubar
   Object f = getParent ();
   while (! (f instanceof Frame))
     f = ((Component) f).getParent ();
   Frame frame = (Frame) f;

   MenuItem miOpen, miSortUp, miSortDown, miSom, miProduct, miExit;
   MenuBar mbMain = new MenuBar();
   Menu mnuFile = new Menu("Bestand");

   miOpen = new MenuItem("Lees breuken");
   miOpen.addActionListener(new ActionListener()
   {
     /**
      * @TODO
      * @param evt ActionEvent
      */
     public void actionPerformed(ActionEvent evt)
     {
       RationaalLijst rlijst = new RationaalLijst();
       try {
         RationaalFile ft = new RationaalFile("breuken.txt", rlijst);
         String dumpResult = rlijst.dump();
         JOptionPane.showMessageDialog(null, dumpResult, "Lees
Breuken", JOptionPane.OK_OPTION);
       } catch ( IOException e ) {
         System.out.println("File not found, or cannot be opened.");
       }

       //Enable MenuItems
       //Probablt best to set this in the try-catch statement...
       //use: mi.enable(); - mi.disable();
//       miSortUp.setEnabled(true);
     }
   });

   miSortUp = new MenuItem("Sorteer <");
   miSortUp.addActionListener(new ActionListener()
   {
     /**
      * @TODO
      * @param evt ActionEvent
      */
     public void actionPerformed(ActionEvent evt)
     {

     }
   });
//    miSortUp.setEnabled(false);

   ... (IRRELEVANT CODE) ...

   miExit = new MenuItem("Afsluiten");
   miExit.addActionListener(new ActionListener()
   {
     public void actionPerformed(ActionEvent evt)
     {
       System.exit(0);
     }
   });

   mnuFile.add(miOpen);
   mnuFile.add(miSortDown);
   mnuFile.add(miSortUp);
   mnuFile.add(miSom);
   mnuFile.add(miProduct);
   mnuFile.add(miExit);
   mbMain.add(mnuFile);
   frame.setMenuBar(mbMain);
 }
}