location authorization alert showing up after app closes - ios

Question

I created a singleton class to handle location authorization because I needed it for several views in my app. So I created the below Location.swift class.
NOTE: I have added correctly into Info.plist, and have looked at several other posts but none seem to address this (at least none I found)
protocol LocationServiceDelegate {
func tracingLocation(currentLocation: CLLocation)
func tracingLocationDidFailWithError(error: NSError)
}
class Location: NSObject,CLLocationManagerDelegate {
var latitude: Double!
var longitude: Double!
var currentLocation : CLLocation!
var locationManager: CLLocationManager?
var lastLocation: CLLocation?
var delegate: LocationServiceDelegate?
static let sharedInstance:Location = {
let instance = Location()
return instance
}()
override init() {
super.init()
self.locationManager = CLLocationManager()
self.locationManager?.delegate = self
guard let locationManagers = self.locationManager else {
return
}
if CLLocationManager.authorizationStatus() == .notDetermined {
locationManagers.requestWhenInUseAuthorization()
}
locationManagers.desiredAccuracy = kCLLocationAccuracyBest
locationManagers.pausesLocationUpdatesAutomatically = false
locationManagers.distanceFilter = 0.1
}
func locationManager(_ manager: CLLocationManager, didFailWithError error: Error) {
}
func locationManager(_ manager: CLLocationManager, didUpdateLocations locations: [CLLocation]) {
guard let location = locations.last else {
return
}
self.lastLocation = location
updateLocation(currentLocation: location)
}
#nonobjc func locationManager(manager: CLLocationManager!, didChangeAuthorizationStatus status: CLAuthorizationStatus) {
switch status {
case .notDetermined:
locationManager?.requestWhenInUseAuthorization()
break
case .authorizedWhenInUse:
locationManager?.startUpdatingLocation()
break
case .authorizedAlways:
locationManager?.startUpdatingLocation()
break
case .restricted:
// restricted by e.g. parental controls. User can't enable Location Services
break
case .denied:
// user denied your app access to Location Services, but can grant access from Settings.app
break
}
}
// Private function
private func updateLocation(currentLocation: CLLocation){
guard let delegate = self.delegate else {
return
}
delegate.tracingLocation(currentLocation: currentLocation)
}
private func updateLocationDidFailWithError(error: NSError) {
guard let delegate = self.delegate else {
return
}
delegate.tracingLocationDidFailWithError(error: error)
}
func startUpdatingLocation() {
print("Starting Location Updates")
self.locationManager?.startUpdatingLocation()
currentLocation = locationManager?.location
Location.sharedInstance.latitude = currentLocation.coordinate.latitude
Location.sharedInstance.longitude = currentLocation.coordinate.longitude
print(Location.sharedInstance.latitude, Location.sharedInstance.longitude)
// self.locationManager?.startMonitoringSignificantLocationChanges()
}
func stopUpdatingLocation() {
print("Stop Location Updates")
self.locationManager?.stopUpdatingLocation()
}
}
My app is crashing, and I think its because the location authorization is not set in the beginning. The funny thing is that the request alert which prompts the user to allow location services doesn't show up until you leave the app.
Once you close the app and accept the location services, the app works fine. So my question is, why isn't the alert showing up?
it is also interesting to note that this is only occurring through an actual device. In the simulator the alert pops up as expected when the initial view is loading.
my first view that is supposed to load and show data is as follows:
import UIKit
import Alamofire
class CurrentWeatherVC: UIViewController {
#IBOutlet weak var locationLabel: UILabel!
#IBOutlet weak var weatherIcon: UIImageView!
#IBOutlet weak var currentTempLabel: UILabel!
#IBOutlet weak var weatherTypeLabel: UILabel!
var currentWeather : CurrentWeather!
override func viewDidLoad() {
super.viewDidLoad()
Location.sharedInstance.locationManager(manager: Location.sharedInstance.locationManager, didChangeAuthorizationStatus: .authorizedWhenInUse)
currentWeather = CurrentWeather()
}
override func viewDidAppear(_ animated: Bool) {
super.viewDidAppear(animated)
Location.sharedInstance.startUpdatingLocation()
currentWeather.downloadWeatherDetails {
self.updateMainUI()
}
}
func updateMainUI() {
//Double value convterted to string for current temp.
//Added the degree symbol here
//For forecast it gets added in before saved into list so be aware of that.
currentTempLabel.text = "\(currentWeather.currentTemp)°"
weatherTypeLabel.text = currentWeather.weatherType
locationLabel.text = currentWeather.cityName
weatherIcon.image = UIImage(named: currentWeather.weatherType)
}
}

Answer 1

I suspect downloadWeatherDetailss implementation uses a dataTask or one of the other NSURLSession methods that run in background.
Make sure to call UI stuff only on the mainQueue:
// ...
DispatchQueue.main.async {
self.updateMainUI()
}
// ...