iOS - CLLocation Manager didUpdateLocations being called in one class but not another? - ios

Question

Hi I'm making a program that gets the users location and puts an according annotation on the map. I started by writing all of the code in the View Controller and it gets the location perfectly. Below is the working code in the view controller.
class MapViewController: UIViewController, CLLocationManagerDelegate {
var annotation = MKPointAnnotation()
var userLocation: CLLocation?
#IBOutlet weak var mapView: MKMapView!
var locationManager:CLLocationManager!
override func viewWillAppear(_ animated: Bool) {
super.viewWillAppear(animated)
determineCurrentLocation()
}
func determineCurrentLocation() {
locationManager = CLLocationManager()
locationManager.delegate = self
locationManager.desiredAccuracy = kCLLocationAccuracyBest
locationManager.requestAlwaysAuthorization()
if CLLocationManager.locationServicesEnabled() {
locationManager.startUpdatingLocation()
}
}
func locationManager(_ manager: CLLocationManager, didUpdateLocations locations: [CLLocation]) {
userLocation = locations[0] as CLLocation
print("user latitude = \(userLocation?.coordinate.latitude)")
print("user longitude = \(userLocation?.coordinate.longitude)")
annotation.coordinate = CLLocationCoordinate2D(latitude: (userLocation?.coordinate.latitude)!, longitude: (userLocation?.coordinate.longitude)!)
annotation.title = "You"
mapView.addAnnotation(annotation)
}
func locationManager(_ manager: CLLocationManager, didFailWithError error: Error) {
print("Error \(error)")
}
However now when I try and recreate almost the exact same code in another swift file. didUpdateLocations never gets called. locationManager.startUpdatingLocation() does get called.
Below is my new swift file which I call from the View Controller. Is there any simple concept I'm missing here because I really don't see why this doesn't work.
import Foundation
import CoreLocation
class SendLocation: NSObject, CLLocationManagerDelegate {
var userLocation: CLLocation?
var locationManager:CLLocationManager!
func sendLocationPost() {
determineCurrentLocation()
}
func determineCurrentLocation() {
locationManager = CLLocationManager()
locationManager.delegate = self
locationManager.desiredAccuracy = kCLLocationAccuracyBest
locationManager.requestAlwaysAuthorization()
print("WHY")
if CLLocationManager.locationServicesEnabled(){
locationManager.startUpdatingLocation()
}
}
func locationManager(_ manager: CLLocationManager, didUpdateLocations locations: [CLLocation]) {
userLocation = locations[0] as CLLocation
print("user latitude = \(userLocation?.coordinate.latitude)")
print("user longitude = \(userLocation?.coordinate.longitude)")
}
func locationManager(_ manager: CLLocationManager, didFailWithError error: Error) {
print("Error \(error)")
}
}
I call it using :
let location = SendLocation()
location.sendLocationPost()`
in my View Controller

Answer 1

This happens because you are not keeping a reference to your SendLocation object.
Make SendLocation a property of your UIViewController.
For example, calling it from a static scope will not keep a reference.
WONT WORK:
static func sendLocation() {
let location = SendLocation()
location.sendLocationPost()
}
WILL WORK
let location = SendLocation()
func sendLocation() {
location.sendLocationPost()
}