File menu item adding

Hi i m added the File menu item creating the views my code look like
final Class viewClass : new Class { Dashboard.class,
Editor.class, Ticket.class, MockupView.class }) {
navigator.addView(viewClass.getSimpleName(), viewClass);
menu.addItem(viewClass.getSimpleName(), new MenuBar.Command() {

            public void menuSelected(MenuItem selectedItem) {
                navigator.navigateTo(viewClass);
            }
        });

but how to add sub menu item any one can help me if you provide me example it will be great full for me-_-

For an example go
here
and click ‘View Source’ in the upper right corner. There are other MenuBar examples as well.