In the following code, I have a LocationManager class which provides the city name of the current location via the @Published property wrapper lastSearchedCity.

Then I have a SearchManagerViewModel class that should be in charge of presenting the city name on SwiftUI views based on some conditions (not currently shown in the code below) via the @Published property wrapper cityName. It properly shows the city name when I call the searchAndSetCity() method from ContentView.swift inside an onAppear modifier.

My issue is that if the user turned Location Services off and turns it back On while he/she is in the ContentView.swift the Text view doesn't update, which is understandable since the searchAndSetCity() method would need to be called again.

How can I call the searchAndSetCity() method located inside the SearchManagerViewModel class every time the locationManagerDidChangeAuthorization(_ manager: CLLocationManager) method is called? I believed this method is called every time the authorization status changes.

LocationManager Class

final class LocationManager: NSObject, ObservableObject, CLLocationManagerDelegate {

    private let locationManager = CLLocationManager()

    @Published var lastSearchedCity = ""

    var hasFoundOnePlacemark:Bool = false

    func checkIfLocationServicesIsEnabled(){
        DispatchQueue.global().async {
            if CLLocationManager.locationServicesEnabled(){
                self.locationManager.delegate = self
                self.locationManager.desiredAccuracy = kCLLocationAccuracyBest/// kCLLocationAccuracyBest is the default
                self.checkLocationAuthorization()
            }else{
                // show message: Services desabled!
            }
        }
    }

    private func checkLocationAuthorization(){
        switch locationManager.authorizationStatus{
        case .notDetermined:
            locationManager.requestWhenInUseAuthorization()
        case .restricted:
            // show message
        case .denied:
            // show message
        case .authorizedWhenInUse, .authorizedAlways:
            /// app is authorized
            locationManager.startUpdatingLocation()
        default:
            break
        }
    }
    func locationManagerDidChangeAuthorization(_ manager: CLLocationManager) {
        checkLocationAuthorization()
    }
    func locationManager(_ manager: CLLocationManager, didUpdateLocations locations: [CLLocation]) {
        hasFoundOnePlacemark = false

        CLGeocoder().reverseGeocodeLocation(manager.location!, completionHandler: {(placemarks, error)-> Void in
            if error != nil {
                self.locationManager.stopUpdatingLocation()
                // show error message
            } 
            if placemarks!.count > 0 {
                if !self.hasFoundOnePlacemark{
                    self.hasFoundOnePlacemark = true
                    let placemark = placemarks![0]

                    self.lastSearchedCity = placemark.locality ?? ""               
                }
                self.locationManager.stopUpdatingLocation()
            }else{
                // no places found
            }
        })
    }
}

SearchManagerViewModel Class

class SearchManagerViewModel: ObservableObject{
    @Published var cityName = "" // use this directly in SwifUI views

    @ObservedObject private var locationManager = LocationManager()

    // Call this directly fron onAppear in SwiftUI views
    // This method is more complex than what is shown here. It handles other things like HTTP requests etc.
    func searchAndSetCity(){
        locationManager.checkIfLocationServicesIsEnabled()
        self.cityName = locationManager.lastSearchedCity
    }
}

ContentView.swift

struct ContentView: View {

    @StateObject private var searchManager = SearchManagerViewModel()

    var body: some View {
        VStack {
            Text(searchManager.cityName)
                .font(.callout)
        }
        .onAppear{
            searchManager.searchAndSetCity()
        }
    }
}

@Hatsushira - Yes I have heard of the Delegate Pattern, it's an option but for some reason I was thinking that something like that could be done with Combine where you comunicate two classes. The Delegate Pattern, for some reason feels anti SwifUI.

The easiest would be to eliminate the SearchManagerViewModel and do everything from the LocationManager class but it would be doing other stuff not releated to locations and I don't really want to do that.

Thank you for your suggestion.

@Hatsushira - Thank you for suggesting the Delegation Pattern, I ended up using it. Thanks.