The screen being mirrored by an external display.
- iOS 4.3+
- Mac Catalyst 13.0+
- tvOS 9.0+
If mirroring is supported and currently active, this property contains the screen object associated with the device’s main screen. This represents the screen being mirrored by the attached display. The value of this property is
nil when mirroring is disabled, not supported, or no screen is connected to the device.
To disable mirroring and use the external display for presenting unique content, create a window and associate it with the corresponding screen object. To re-enable mirroring, remove the window from the corresponding screen object.