didUpdateLocations called every time when viewWillAppear for Significant Location Change - ios

Question

I am using CLLocationManager and MKMapView in same UIViewController.
I want to call an API only when the significant location change.
import UIKit
import CoreLocation
import MapKit
class ViewController: UIViewController,CLLocationManagerDelegate,MKMapViewDelegate {
#IBOutlet weak var mapView: MKMapView!
var locationManager = CLLocationManager()
override func viewDidLoad() {
super.viewDidLoad()
// Do any additional setup after loading the view, typically from a nib.
self.locationManager.requestAlwaysAuthorization()
self.locationManager.delegate = self
self.locationManager.startMonitoringSignificantLocationChanges()
self.locationManager.desiredAccuracy = kCLLocationAccuracyBestForNavigation
self.locationManager.distanceFilter = 500
mapView.showsUserLocation = true
}
override func viewWillAppear(_ animated: Bool) {
super.viewWillAppear(true)
}
override func didReceiveMemoryWarning() {
super.didReceiveMemoryWarning()
// Dispose of any resources that can be recreated.
}
public func locationManager(_ manager: CLLocationManager, didUpdateLocations locations: [CLLocation]) {
print("locations \(locations)")
}
}
In this, the main issue is whenever I make the app background and foreground didUpdateLocations get called. I want it to be called only when significant location change, not every time when viewWillAppear called.
I found its because of MKMapView, didUpdateLocations is being called.

Answer 1

You can manually check the distance with last saved location. Try this.
var lastLocation: CLLocation?
public func locationManager(_ manager: CLLocationManager, didUpdateLocations locations: [CLLocation]) {
if let lastLocation = lastLocation, let newLocation = locations.last {
if (lastLocation.distance(from: newLocation) < manager.distanceFilter) {
return
}
}
print("locations \(locations)")
lastLocation = locations.last
}

Answer 2

You can save the last locations and check inside didUpdateLocations method, if not same the take appropriate action.
func locationManager(_ manager: CLLocationManager, didUpdateLocations locations: [CLLocation]) {
let location : CLLocation = locations.last!
if location.coordinate.latitude != lastLat && location.coordinate.longitude != lastLon{
// take action
}
}