[news.eclipse.platform.swt] Re: JFace Dialog - change default focus

[Matthew Hall <matthall@xxxxxxxxxxxxxxxxx>]

Joe Gagnon wrote:
> Matthew Hall wrote:
>
> > You can cause the filter to be removed as the dialog is closed by 
> > adding a SWT.Dispose listener to the composite created in 
> > createDialogArea:
>
> > composite.addListener(SWT.Dispose, new Listener() {
> >    public void handleEvent(Event e) {
> >      display.removeListener(SWT.Traverse, overrideTraversalListener);
> >    }
> > });
>
> We have overridden the buttonPressed() method (for other reasons) and 
> this is where I'm removing the listener. Is this an acceptable alternative?
>
>  protected void buttonPressed(int buttonId) {
>    ...
>
>    log.debug("Removing traverse filter");
>    getShell().getDisplay().removeFilter(SWT.Traverse, listener);
>
>    super.buttonPressed(buttonId);
>  }

What if the OK button is enabled but your field validators prevent the 
window from closing?  The traversals will return to normal behavior and 
your interface will be inconsistent.  I would remove the traversal 
override when the dialog area is disposed.

Another approach to knowing when to convert Enter-traversals to 
Tab-traversals is to overload createButton() to keep a list of all 
buttons in the button bar:

protected Button createButton (Composite parent, int id, String label, 
boolean defaultButton) {
  Button button = super.createButton(parent, id, label, defaultButton);
  buttons.add(result);
  return button;
}

Then override traversal for all but those buttons:

Listener traversalOverrideListener = new Listener() {
  public void handleEvent(Event e) {
    if ( e.detail == SWT.TRAVERSE_RETURN &&
         display.getActiveShell() == shell &&
         !buttons.contains(e.widget) ) {
      event.detail = SWT.TRAVERSE_NEXT;
    }
  }
}

Matthew