Instance Property


The window to use when presenting a storyboard.


optional var window: UIWindow? { get set }


This property contains the window used to present the app’s visual content on the device’s main screen.

Implementation of this property is required if your app’s Info.plist file contains the UIMainStoryboardFile key. Fortunately, the Xcode project templates usually include a synthesized declaration of the property automatically for the app delegate. The default value of this synthesized property is nil, which causes the app to create a generic UIWindow object and assign it to the property. If you want to provide a custom window for your app, you must implement the getter method of this property and use it to create and return your custom window.

For more information about the UIMainStoryboardFile key, see Information Property List Key Reference.

Beta Software

This documentation contains preliminary information about an API or technology in development. This information is subject to change, and software implemented according to this documentation should be tested with final operating system software.

Learn more about using Apple's beta software