Description

The design of the afterNavigation method in the AppLayout is contradictory to the one of the AfterNavigationObserver. While in the method of the ANO interface the UI can be accessed via getUI(), the method of the AppLayout does not yet provide it. This is due to the place where the method is called by the class.

This may lead to confusion for devs, as they might expect the same behavior based on the same method naming and similar documentation.

Expected outcome

The UI should be available when calling getUI inside the AppLayouts afterNavigation.

Possible solutions:

1. Override getUI in the AppLayout to return UI.getCurrent() as an alternative, if the component has not yet been attached to the UI. Not sure if this could lead to a false UI in any normal case?
2. Let AppLayout implement the AfterNavigationObserver interface and move the call of afterNavigation there. This could be classified as a breaking change as it might interfere with any manual implementation of the interface. It would however align more with our base interfaces and the intended usage.

Minimal reproducible example

public class MainLayout extends AppLayout {
    ...

    @Override
    protected void afterNavigation() {
        getUI().orElseThrow(IllegalStateException::new);
    }
    ...
}

Steps to reproduce

1. Create a starter app from our website.
2. Go to the MainLayout.
3. Call getUI() inside the pre-implemented afterNavigation method. The returned value is an empty optional.

Environment

Vaadin version(s): 24.1.8
OS: Windows

Browsers

Issue is not browser related