Onchange of variable in class - swift

Question

I have a class such as:
class LocationViewModel: NSObject, ObservableObject, CLLocationManagerDelegate {
#Published var lastSeenLocation: CLLocation?
#Published var currentPlacemark: CLPlacemark?
#Published var authorizationStatus: CLAuthorizationStatus
private let locationManager: CLLocationManager
override init() {
locationManager = CLLocationManager()
authorizationStatus = locationManager.authorizationStatus
super.init()
locationManager.delegate = self
locationManager.desiredAccuracy = kCLLocationAccuracyBest
locationManager.startUpdatingLocation()
}
func requestPermission() {
locationManager.requestAlwaysAuthorization()
}
func locationManagerDidChangeAuthorization(_ manager: CLLocationManager) {
authorizationStatus = manager.authorizationStatus
}
}
I'm trying to check if last seen location = cordinates using this code:
let radius: Double = 5 // miles
let userLocation = CLLocation(latitude: locationViewModel.lastSeenLocation?.coordinate.latitude, longitude: locationViewModel.lastSeenLocation?.coordinate.longitude)
let venueLocation = CLLocation(latitude: 51.500909, longitude: -0.177366)
let distanceInMeters = userLocation.distanceFromLocation(venueLocation)
let distanceInMiles = distanceInMeters * 0.00062137
if distanceInMiles < radius {
// user is near the venue
}
The only problem is, that I don't know how to run that code to check constantly. I was thinking .onChange but couldn't figure out how to test for lastSeenlocation in a class. What can I do?

Answer 1

I found a solution here.
For a quick overview:
//I put this code in my LocationViewModel class
func getUserLocation() {
locationManager.startUpdatingLocation()
locationManager.delegate = self
}
func locationManager(_ manager: CLLocationManager, didUpdateLocations locations: [CLLocation]) {
if let location = locations.last {
print("latitude: \(location.coordinate.latitude), longitude: \(location.coordinate.longitude)")
}
}
//I put this code in my ContentView()
.onAppear {
locationViewModel.getUserLocation()
}
Then it prints your latitude & longitude every time your location changes.