Equivalent of UIApplication.shared.preferredContentSizeCategory in app extension

Question

My open source library needs to be able to call UIApplication.shared.preferredContentSizeCategory. But UIApplication.shared is unavailable in extensions. The build error suggests that I find a view controller-based way to solve my problem, but I'm writing a library, so I don't have access to any view controllers. Is there a way to get the root view controller of an extension, or a way to get the outermost UITraitEnvironment?

I support iOS 9+, but this feature could be 10+ if that makes it possible.

Answer 1

You can use UIScreen.main.traitCollection.preferredContentSizeCategory. The preferredContentSizeCategory property is available on iOS 10 or later.