how to convey the coordinate from didUpdateLocation to some view controller? - ios

Question

I am trying to make LocationService class that will convey userCoordinate, so it will be reusable for more than one View Controller
import UIKit
import CoreLocation
class LocationService: NSObject {
let manager = CLLocationManager()
override init() {
super.init()
manager.delegate = self
manager.desiredAccuracy = kCLLocationAccuracyBest
manager.startUpdatingLocation()
}
func getPermission() {
// to ask permission to the user by showing an alert (the alert message is available on info.plist)
if CLLocationManager.authorizationStatus() == .notDetermined {
manager.requestWhenInUseAuthorization()
}
}
func checkLocationAuthorizationStatus() -> CLAuthorizationStatus{
return CLLocationManager.authorizationStatus()
}
}
extension LocationService : CLLocationManagerDelegate {
func locationManager(_ manager: CLLocationManager, didChangeAuthorization status: CLAuthorizationStatus) {
if status == .authorizedWhenInUse {
manager.requestLocation()
}
}
func locationManager(_ manager: CLLocationManager, didFailWithError error: Error) {
print("location is not available: \(error.localizedDescription)")
}
func locationManager(_ manager: CLLocationManager, didUpdateLocations locations: [CLLocation]) {
guard let userLocation = locations.first else {return}
if userLocation.horizontalAccuracy > 0 {
manager.stopUpdatingLocation()
let coordinate = Coordinate(location: userLocation)
// how to convey this coordinate for several view controller?
}
}
}
as you can see in the didUpdateLocations method that comes from CLLocationManagerDelegate, the coordinate need some time to be generated.
but I don't know how to convey that user coordinate, I think it will use completion handler but I don't know how to get that
so let say in HomeVC, I will call that LocationService to get the userCoordinate
import UIKit
class HomeVC: UIViewController {
let locationService = LocationService()
override func viewDidLoad() {
super.viewDidLoad()
// get coordinate, something like this
locationService.getCoordinate()
}
}

Answer 1

You can use Notification like Paulw11 said. You need to update didUpdateLocations. This is the place where you are going to post notification.
func locationManager(_ manager: CLLocationManager, didUpdateLocations locations: [CLLocation]) {
guard let userLocation = locations.first else {return}
if userLocation.horizontalAccuracy > 0 {
manager.stopUpdatingLocation()
let coordinate = Coordinate(location: userLocation)
let locationDictionary: [String: Double] = ["lat": location.coordinate.latitude,
"long": location.coordinate.longitude]
NotificationCenter.default.post(name: NSNotification.Name(rawValue: "YourNotificationNameAsYouWantToNameIt"), object: nil, userInfo: locationDictionary)
}
}
Now in viewDidLoad in every view controller that you want this location you need to observe this notification:
NotificationCenter.default.addObserver(self, selector: #selector(doSomethingAboutLocation(_:)), name: NSNotification.Name(rawValue: "YourNotificationNameAsYouWantToNameIt"), object: nil)
Then access your location like this in your function called from selector:
#objc func doSomethingAboutLocation(_ notification: Notification) {
if let notificationInfo = notification.userInfo {
let coordinate = CLLocation(latitude: notificationInfo["lat"] as! Double, longitude: notificationInfo["long"] as! Double)
// use your coordinate as you want
}
}