---
title: Handling User Activity
framework: watchkit
role: article
role_heading: Article
path: watchkit/handling-user-activity
---

# Handling User Activity

Detect and respond to user activity information from Handoff or a complication.

## Overview

Overview SwiftUI provides the onContinueUserActivity(_:perform:) modifier to handle incoming NSUserActivity objects. This replaces the WatchKit extension delegate’s handle(_:) method. For example, if you create a complication descriptor using the init(identifier:displayName:supportedFamilies:userActivity:) initializer to pass in an NSUserActivity object, when the user taps the corresponding complication, the system activates your app and passes the activity object to your onContinueUserActivity(_:perform:) modifiers. You can use the activity object to navigate to the corresponding content in your app. // Create a list of the user's favorite cities. List(favoriteCities) { city in          // Create a navigation link for each city.     // Activate the link if it is for the selected city.     NavigationLink(city.name,                    destination: CityDetailView(city: city),                    isActive: checkActive(city: city))                  .onContinueUserActivity(viewCityFromComplication) { activity in                          // App received a user activity object.             // Check to see whether it has a city index in the userInfo dictionary.             if let id = activity.userInfo?[cityIDKey] as? String {                                  // Navigate to the specified city.                 selectedCity = allCities[id]             }             else {                                  // Display the favorite city list.                 selectedCity = nil             }         } } Note that in this example, selectedCity is a state variable that holds a City instance. The checkActive(city:) method creates a binding that indicates whether the given city is the currently selected city. @State var selectedCity: City? = nil

// Returns a binding that determines whether a given // city is the currently selected city. func checkActive(city: City) -> Binding<Bool> {     Binding {         selectedCity == city     }     set: {         // If the binding is set to true, set the selected city         // to the provided city.         if $0 {             selectedCity = city         }         // if the binding is set to false,         // and the selected city is set to the provided city,         // clear the selected city.         else if selectedCity == city {             selectedCity = nil         }     } }

## See Also

### Responding to life cycle events

- [Handling Common State Transitions](watchkit/handling-common-state-transitions.md)
- [Working with the watchOS app life cycle](watchkit/working-with-the-watchos-app-life-cycle.md)
- [Taking advantage of frontmost app state](watchkit/taking-advantage-of-frontmost-app-state.md)