Why userLocation returns (-180.0,-180.0) coordinates on Mapbox? - ios

Question

I use Mapbox with Swift 4 and I have a problem when I want to display the user location. I don't understand why the user location is not set as it should be.
I would get the user location coordinates in the viewDidLoad() method. To do so, I have set MGLMapViewDelegate and CLLocationManagerDelegate in my ViewController declaration. Then, in my viewDidLoad() I have:
// Mapview configuration
let mapView = MGLMapView(frame: self.mapView.bounds)
mapView.autoresizingMask = [.flexibleWidth, .flexibleHeight]
mapView.showsUserLocation = true
mapView.setUserTrackingMode(.follow, animated: true)
mapView.delegate = self
self.mapView.addSubview(mapView)
// User location
print("User location:")
print(mapView.userLocation!.coordinate)
But I get this:
CLLocationCoordinate2D(latitude: -180.0, longitude: -180.0)
I think it is because the location is not set when the view loads, but I need to get values in viewDidLoad().
What should I do, and why the line mapView.userLocation!.coordinate doesn't work?
EDIT
In fact, I want to use MapboxDirections to display on the map a line between the user location and a fixed point. To do it, I use this code (see the first comment):
let waypoints = [
// HERE I would use the user location coordinates for my first Waypoint
Waypoint(coordinate: CLLocationCoordinate2D(latitude: 38.9131752, longitude: -77.0324047), name: "Mapbox"),
Waypoint(coordinate: CLLocationCoordinate2D(latitude: 38.8977, longitude: -77.0365), name: "White House"),
]
let options = RouteOptions(waypoints: waypoints, profileIdentifier: .automobileAvoidingTraffic)
options.includesSteps = true
_ = directions.calculate(options) { (waypoints, routes, error) in
guard error == nil else {
print("Error calculating directions: \(error!)")
return
}
if let route = routes?.first, let leg = route.legs.first {
print("Route via \(leg):")
let distanceFormatter = LengthFormatter()
let formattedDistance = distanceFormatter.string(fromMeters: route.distance)
let travelTimeFormatter = DateComponentsFormatter()
travelTimeFormatter.unitsStyle = .short
let formattedTravelTime = travelTimeFormatter.string(from: route.expectedTravelTime)
print("Distance: \(formattedDistance); ETA: \(formattedTravelTime!)")
if route.coordinateCount > 0 {
// Convert the route’s coordinates into a polyline.
var routeCoordinates = route.coordinates!
let routeLine = MGLPolyline(coordinates: &routeCoordinates, count: route.coordinateCount)
// Add the polyline to the map and fit the viewport to the polyline.
mapView.addAnnotation(routeLine)
mapView.setVisibleCoordinates(&routeCoordinates, count: route.coordinateCount, edgePadding: .zero, animated: true)
}
}
}

Answer 1

Larme is correct: the user's location typically isn't available yet in -viewDidLoad. Use the -mapView:didUpdateUserLocation: delegate method to be notified when the user's location becomes available and when it updates.
If you need the user’s location before a map is shown, consider running your own CLLocationManager.
-180, -180 is the kCLLocationCoordinate2DInvalid constant from Core Location. You should typically check if CLLocationCoordinate2DIsValid() before trying to display CLLocationCoordinate2D on a map.

Answer 2

Sergey Kargopolov has a great example of how to obtain the user location using CLLocationManager and CLLocationManagerDelegate. Here is his code:
class ViewController: UIViewController, CLLocationManagerDelegate {
var locationManager:CLLocationManager!
override func viewDidLoad() {
super.viewDidLoad()
}
override func viewWillAppear(_ animated: Bool) {
super.viewWillAppear(animated)
determineMyCurrentLocation()
}
func determineMyCurrentLocation() {
locationManager = CLLocationManager()
locationManager.delegate = self
locationManager.desiredAccuracy = kCLLocationAccuracyBest
locationManager.requestAlwaysAuthorization()
if CLLocationManager.locationServicesEnabled() {
locationManager.startUpdatingLocation()
//locationManager.startUpdatingHeading()
}
}
func locationManager(_ manager: CLLocationManager, didUpdateLocations locations: [CLLocation]) {
let userLocation:CLLocation = locations[0] as CLLocation
// Call stopUpdatingLocation() to stop listening for location updates,
// other wise this function will be called every time when user location changes.
// manager.stopUpdatingLocation()
print("user latitude = \(userLocation.coordinate.latitude)")
print("user longitude = \(userLocation.coordinate.longitude)")
}
func locationManager(_ manager: CLLocationManager, didFailWithError error: Error)
{
print("Error \(error)")
}
}