Vaadin : preventing MenuBar from closing when MenuBarRootItem is clicked

Question

I am using vaadin 24. I have a MenuBar and I would like to modify the default behavior of MenuBar so that it doesn't close when I click on the items (to be able to click them several times). Do someone know how to achieve this please ?

Here's my code :

MenuBar menu = new MenuBar();
menu.addItem(VaadinIcon.PLUS.create(), event -> increase());
menu.addItem(VaadinIcon.MINUS.create(), event -> decrease());

Answer 1

It's a known omission. Here's a workaround from the ticket:

/*
 * Do not close the overlay ({@link SubMenu} containing this menu item when clicked.
 */
public class RetainOpenedMenuItemDecorator {
    public static final String CHECKED_ATTR = "menu-item-checked";
    private final MenuItem menuItem;

    public RetainOpenedMenuItemDecorator(MenuItem menuItem) {
        this.menuItem = menuItem;
        menuItem.getElement().addEventListener("click", e -> {
            if (!menuItem.isCheckable()) {
                return;
            }
            // needed because UI change is also prevented
            if (menuItem.isChecked()) {
                menuItem.getElement().executeJs("this.setAttribute('"+ CHECKED_ATTR + "', '')");
            } else {
                menuItem.getElement().executeJs("this.removeAttribute('"+ CHECKED_ATTR + "')");
            }
        }).addEventData("event.preventDefault()");
    }

    public MenuItem getMenuItem() {
        return menuItem;
    }

    public static void keepOpenOnClick(MenuItem menuItem) {
        new RetainOpenedMenuItemDecorator(menuItem);
    }

    public static void keepOpenOnClick(SubMenu subMenu) {
        subMenu.getItems().forEach(RetainOpenedMenuItemDecorator::keepOpenOnClick);
    }
}