What I want is simple - if the geo-position has been determined, a certain method should be called that checks this geo-position.

here is my LocationManager:

final class LocationManager: NSObject, ObservableObject, CLLocationManagerDelegate {
    
    var lastKnownLocation: CLLocationCoordinate2D  = CLLocationCoordinate2D(latitude: 0, longitude: 0)
    
    @Published var authorizationStatus: CLAuthorizationStatus = .notDetermined
    @Published var locationState: LocationState = .loading
    
    private var locationMngr: CLLocationManager!
    
    func requestLocation() {
        self.locationMngr = CLLocationManager()
        self.locationMngr.delegate = self
        
        switch self.locationMngr.authorizationStatus {
        case .notDetermined:
            self.locationMngr.requestWhenInUseAuthorization()
        case .authorizedWhenInUse,
             .authorizedAlways:
            self.locationMngr.startUpdatingLocation()
        default:
            print("Location access denied or restricted")
        }
    }

    [...]
    
    
    func locationManager(_ manager: CLLocationManager, didUpdateLocations locations: [CLLocation]) {
        // this is always printed !
        print("Location updated: \(locations)")
        self.locationMngr.stopUpdatingLocation()
        
        guard let location = locations.first else {
            print("No location data available")
            self.locationState = .notAvailable
            return
        }
        
        self.lastKnownLocation = location.coordinate
        self.locationState = .changed
        
    }
    
}

enum LocationState: Equatable {
    case loading
    case changed
    case notAvailable
    
    static func == (lhs: LocationState, rhs: LocationState) -> Bool {
        switch (lhs, rhs) {
        case (.loading, .loading):
            return true
        case (.changed, .changed):
            return true
        case (.notAvailable, .notAvailable):
            return true
        default:
            return false
        }
    }
}

Now the View:

struct RegistrationInfoView: View {
    
    @StateObject private var locationManager = LocationManager()
    
    var body: some View {
        VStack {

            // show some info text first
            
            [...]
            
            ButtonFilled("Next") {
                locationManager.requestLocation()
            }
            
        }
        
        .onChange(of: locationManager.locationState) {
            print("onChange: Location changed")
            
            if locationManager.locationState == .changed {

                checkLocationIsInArea()

            } 
        }
        
    }
    
    [...]
}

onChange method is not triggered. I can see that didUpdateLocations is triggered and position is available.

Perhaps XY-Problem or I'm using onChange wrong. Any idea?

What I want is simple - if the geo-position has been determined, a certain method should be called that checks this geo-position.

here is my LocationManager:

final class LocationManager: NSObject, ObservableObject, CLLocationManagerDelegate {
    
    var lastKnownLocation: CLLocationCoordinate2D  = CLLocationCoordinate2D(latitude: 0, longitude: 0)
    
    @Published var authorizationStatus: CLAuthorizationStatus = .notDetermined
    @Published var locationState: LocationState = .loading
    
    private var locationMngr: CLLocationManager!
    
    func requestLocation() {
        self.locationMngr = CLLocationManager()
        self.locationMngr.delegate = self
        
        switch self.locationMngr.authorizationStatus {
        case .notDetermined:
            self.locationMngr.requestWhenInUseAuthorization()
        case .authorizedWhenInUse,
             .authorizedAlways:
            self.locationMngr.startUpdatingLocation()
        default:
            print("Location access denied or restricted")
        }
    }

    [...]
    
    
    func locationManager(_ manager: CLLocationManager, didUpdateLocations locations: [CLLocation]) {
        // this is always printed !
        print("Location updated: \(locations)")
        self.locationMngr.stopUpdatingLocation()
        
        guard let location = locations.first else {
            print("No location data available")
            self.locationState = .notAvailable
            return
        }
        
        self.lastKnownLocation = location.coordinate
        self.locationState = .changed
        
    }
    
}

enum LocationState: Equatable {
    case loading
    case changed
    case notAvailable
    
    static func == (lhs: LocationState, rhs: LocationState) -> Bool {
        switch (lhs, rhs) {
        case (.loading, .loading):
            return true
        case (.changed, .changed):
            return true
        case (.notAvailable, .notAvailable):
            return true
        default:
            return false
        }
    }
}

Now the View:

struct RegistrationInfoView: View {
    
    @StateObject private var locationManager = LocationManager()
    
    var body: some View {
        VStack {

            // show some info text first
            
            [...]
            
            ButtonFilled("Next") {
                locationManager.requestLocation()
            }
            
        }
        
        .onChange(of: locationManager.locationState) {
            print("onChange: Location changed")
            
            if locationManager.locationState == .changed {

                checkLocationIsInArea()

            } 
        }
        
    }
    
    [...]
}

onChange method is not triggered. I can see that didUpdateLocations is triggered and position is available.

Perhaps XY-Problem or I'm using onChange wrong. Any idea?

• swift
• swiftui

• Are you sure that didUpdateLocations is called on the main thread? – Sweeper Commented 9 hours ago
• "What I want is simple - if the geo-position has been determined, a certain method should be called that checks this geo-position." - you don't need a SwiftUI view to do this. Actually, you can use the Observable object to perform whatever computation, and then compute and publish a "view state" which the view observes to render itself. – CouchDeveloper Commented 9 hours ago
• You don’t need onChange put your logic inside the object in a combine pipeline and assign the result to a published var – malhal Commented 9 hours ago
• Note you also need to have the appropriate Privacy - Location Usage description and Privacy - Location When in Use Usage Description in your Info.plist. With those settings, your code works for me on real iOS 18 device. – workingdog support Ukraine Commented 7 hours ago
• My guess would be that you are using multiple instances. But that equatable implementation is very problematic. That is what SwiftUI uses to decide when to call it – lorem ipsum Commented 6 hours ago

2 Answers 2

Here is my test code that works for me, the .onChange(of: locationManager.locationState) is called as expected. On macOS Sequoia 15.5, using Xcode 16.3, target iOS-18.4, tested on real iOS device.

Note you also need to have the appropriate Privacy - Location Usage Description and Privacy - Location When in Use Usage Description in your Info.plist.

The first time you run the App, it asks for permition. You then have to tap the Next button again to start the location updating.

Let us know if this code does not work for you.

If it does not work with your own code, show a minimal reproducible code that produces your issue, see: minimal code.

struct ContentView: View {
    var body: some View {
        RegistrationInfoView()
    }
}

struct RegistrationInfoView: View {
    @StateObject private var locationManager = LocationManager()
    
    var body: some View {
        VStack {
            Button("Next") {
                locationManager.requestLocation()
            }
        }
        .onChange(of: locationManager.locationState) {
            print("---> onChange locationState: \(locationManager.locationState)")
            if locationManager.locationState == .changed {
                print("---> onChange location: \(locationManager.lastKnownLocation)")
            }
        }
    }
}

final class LocationManager: NSObject, ObservableObject, CLLocationManagerDelegate {
    
    var lastKnownLocation: CLLocationCoordinate2D = CLLocationCoordinate2D(latitude: 0, longitude: 0)
    
    @Published var authorizationStatus: CLAuthorizationStatus = .notDetermined
    @Published var locationState: LocationState = .loading

    private var locationMngr = CLLocationManager()
    
    override init() {
        super.init()
        self.locationMngr.delegate = self
    }
    
    func requestLocation() {
        print("\nrequestLocation")
        switch self.locationMngr.authorizationStatus {
        case .notDetermined:
            print("notDetermined")
            self.locationMngr.requestWhenInUseAuthorization()
        case .authorizedWhenInUse, .authorizedAlways:
            print("authorizedWhenInUse startUpdatingLocation")
            self.locationMngr.startUpdatingLocation()
        default:
            print("Location access denied or restricted")
        }
    }

    func locationManager(_ manager: CLLocationManager, didUpdateLocations locations: [CLLocation]) {

        print("---> Location updated: \(locations)")

        self.locationMngr.stopUpdatingLocation()
        guard let location = locations.first else {
            print("------> No location data available")
            self.locationState = .notAvailable
            return
        }
        self.lastKnownLocation = location.coordinate
        print("---> lastKnownLocation \(lastKnownLocation)\n")
        self.locationState = .changed
    }
}

enum LocationState {
    case loading
    case changed
    case notAvailable
}

ok it seems to be an bug in swiftui. If I'm using onChange on a Spacer() it works:

struct RegistrationInfoView: View {
    
    @StateObject private var locationManager = LocationManager()
    
    var body: some View {
        VStack {

            // show some info text first
            
            [...]

            Spacer()
            .onChange(of: locationManager.locationState) {
                print("onChange: Location changed")
                if locationManager.locationState == .changed {
                    checkLocationIsInArea()
                } 
            }
            
            ButtonFilled("Next") {
                locationManager.requestLocation()
            }
        }
    }
    
    [...]
}