# userActivity An object that encapsulates a user activity the document supports. ``` var userActivity: NSUserActivity? { get set } ``` ## Discussion [`NSDocument`](/documentation/AppKit/NSDocument) automatically creates objects. The system makes user activities eligible for Handoff if the document is iCloud-based and the app’s `Info.plist` property list file includes a `CFBundleDocumentTypes` key of `NSUbiquitousDocumentUserActivityType`. The value of `NSUbiquitousDocumentUserActivityType` is a string that represents the object’s activity type. The document’s URL is in the object’s dictionary with the [`NSUserActivityDocumentURLKey`](/documentation/AppKit/NSUserActivityDocumentURLKey). In macOS, objects that [`NSDocument`](/documentation/AppKit/NSDocument) manage automatically become current when any of the document window controller’s windows become main. Otherwise, you need to invoke at appropriate times. AppKit automatically invalidates any objects that have no associated documents or responders. You can use this property from any thread. It’s KVO-observable in case you share the [`NSDocument`](/documentation/AppKit/NSDocument) object with other objects that need to be in sync as the document moves into and out of iCloud. ## See Also [`NSDocument`](/documentation/AppKit/NSDocument) An abstract class that defines the interface for macOS documents. --- Copyright © 2026 Apple Inc. All rights reserved. | [Terms of Use](https://www.apple.com/legal/internet-services/terms/site.html) | [Privacy Policy](https://www.apple.com/privacy/privacy-policy)