An object encapsulating a user activity supported by this responder.
- iOS 8.0+
- tvOS 9.0+
By setting the
user property on a responder, the
NSUser object becomes managed by UIKit. User activities managed by UIKit are saved automatically at appropriate times. You can lazily add state data representing the user’s activity via the
update override. Multiple responders can share a single
NSUser instance, in which case they all get an
A responder object can set its
user property to
nil if it no longer wants to participate. Any
NSUser objects that are managed by UIKit but which have no associated responders (or documents) are automatically invalidated.