ApplicationView

The ApplicationView class is needed to retrieve the "visible bounds" of the screen - especially on mobile devices like Android and iOS where we have a status bar and navigation bar. This concept has been mostly dropped in WinAppSDK (at least for now), so calling ApplicationView.GetForCurrentView throws an exception. To keep this functionality internally we are using ApplicationView.GetForWindowId method, which returns a Window-specific instance.

For easier access to the VisibleBounds and TrueVisibleBounds within our codebase, you can utilize the XamlRoot.VisualTree.VisibleBounds and XamlRoot.VisualTree.TrueVisibleBounds properties. This property also works in windowless scenarios like Uno Islands, where it just returns the plain island bounds.

Window initialization

When Window is constructed before application is initialized (e.g. before Application.Current is set), we do not actually construct its content, as that would cause issues on mobile targets (where UI can be created only after a certain app initialization is done. Hence we delay this initialization and run it manually when the application is initialized. If the window is created later in the lifetime of the application, we initialize it immediately. The initialization is done by calling Window.Initialize method.