The complete set of traits for the current environment.
- iOS 13.0+
- Mac Catalyst 13.0+
- tvOS 13.0+
UIKit updates the value of this property before calling several well-known methods of
UIPresentation. The trait collection contains a complete set of trait values describing the current environment, and does not include unspecified or unknown values.
UIKit stores the value for this property as a thread-local variable, so access to it is fast. Also, changing the traits on a nonmain thread does not affect the current traits on your app's main thread.