Is this acceptable use of location authorization callback? - ios

Question

I have implemented a location authorization callback function and it works, but looking over the code I seem to have got the function to trigger but never actually use the function as intended. Please can you comment on how bad I am being and if it is acceptable to do what I have done.
import UIKit
import CoreLocation
class ViewController___Main_menu: UIViewController, CLLocationManagerDelegate {
let locationManager = CLLocationManager()
override func viewDidLoad() {
super.viewDidLoad()
locationManager.delegate = self
locationManager.desiredAccuracy = kCLLocationAccuracyBest
locationManager.requestWhenInUseAuthorization()
if CLLocationManager.locationServicesEnabled() {
print("services are enabled")
switch CLLocationManager.authorizationStatus() {
case .notDetermined:
print("Not determined")
case .restricted:
print("Resticted")
case .denied:
print("Denied")
case .authorizedAlways, .authorizedWhenInUse:
print("Access")
#unknown default:
print("unknown error")
}
} else {
print("not enabled")
}
}
public func locationManager(_ manager: CLLocationManager, didChangeAuthorization status: CLAuthorizationStatus){
print("Status: \(status)")
switch CLLocationManager.authorizationStatus() {
case .notDetermined:
print("Not determined")
case .restricted:
print("Resticted")
case .denied:
print("Denied")
case .authorizedAlways, .authorizedWhenInUse:
print("Access")
#unknown default:
print("unknown error")
}
}
}

Answer 1

It's looks like you're requesting access to location services and straight after that checking what the authorization status is, expecting it to be available immediately. This isn't the way it works. When you request location with locationManager.requestWhenInUseAuthorization the request happens asynchronously.
When the location status changes then it will call to the function you're included locationManager(_:didChangeAuthorization) with the new status. This will happen when the user taps "Allow" or "Deny" on the prompt that appears. It can also happen when they go into the settings and change the permissions there
So to make it more clear, check and log the authorization status before requesting location. Use the following methods to know if the location request succeeded or failed:
func locationManager(CLLocationManager, didUpdateLocations: [CLLocation])
func locationManager(CLLocationManager, didFailWithError: Error)
You would use the CLLocationManager.locationServicesEnabled() check to wrap the request for location services. If location is turned off for the device then requesting location will just cause an error.