The screen on which the window is displayed.
- iOS 3.2+
- tvOS 9.0+
By default, this property is set to the primary device screen. If additional screens are attached to the device, you can assign a different screen object to display the window on that screen. A window is always displayed on only one screen.
Moving windows from screen to screen is a relatively expensive operation and should not be done in performance-sensitive code. Instead, it’s recommended that you change the screen before displaying the window the first time. Changing the screen of a window that has not yet been ordered onto the screen has no significant additional cost.