(no subject)

[kynn]

   Date: Mon, 14 Jan 2002 12:36:16 -0800
   To: [EMAIL PROTECTED]
   From: Dmitry Beransky <[EMAIL PROTECTED]>
   Subject: Re: combo box vs "Java Applet Window"

   This happens, because the popup is created as a lightweight component and 
   lightweight components cannot be drawn outside of their parent window's 
   client area.  When the list is long enough, the combo box code properly 
   realizes that and creates a heavyweight popup instead.  My guess is that 
   there is a bug in JComboBox's code responsible for deciding when to create 
   a heavy-weight popup.  A work around would be to force the component always 
   to use the heavyweight popup by setting the lightWeightPopupEnabled 
   property to false.


Actually, I just realized that this may not work, because
showInputDialog uses a JDialog for display, and the docs for JDialog's
main constructor state:

  NOTE: Any popup components (JComboBox, JPopupMenu, JMenuBar) created
  within a modal dialog will be forced to be lightweight.


I've tried to determine where the creation of JComboBox comes in the
execution of JOptionPane.showInputDialog, and the whole thing is
mysterious.  The code for showInputDialog is:

    public static Object showInputDialog(Component parentComponent, Object message,
                      String title, int messageType, Icon icon,
                      Object[] selectionValues, Object initialSelectionValue) {
        JOptionPane    pane = new JOptionPane(message, messageType,
                                              OK_CANCEL_OPTION, icon,
                                              null, null);

        pane.setWantsInput(true);
        pane.setSelectionValues(selectionValues);
        pane.setInitialSelectionValue(initialSelectionValue);

        JDialog        dialog = pane.createDialog(parentComponent, title);

        pane.selectInitialValue();
        dialog.show();

        Object value = pane.getInputValue();

        if(value == UNINITIALIZED_VALUE)
            return null;
        return value;
    }

The only line I can imagine leads to creating the JComboBox is:

        pane.setSelectionValues(selectionValues);

but setSelectionValues is just:

    public void setSelectionValues(Object[] newValues) {
        Object[]           oldValues = selectionValues;

        selectionValues = newValues;
        firePropertyChange(SELECTION_VALUES_PROPERTY, oldValues, newValues);
        if(selectionValues != null)
            setWantsInput(true);
    }

Maybe some property listener reacts to firePropertyChange to make the
JComboBox, but this would be a very strange way to produce the input
dialog, and, at any rate, I cannot trace it.  Does anybody know how it
is that a JComboBox comes to be used by showInputDialog?

Thanks!

kj

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