Repeating location data with CLLocation - ios

Question

This is a really basic outlay of what I am using...
import UIKit
import MapKit
import CoreLocation
class ViewController: UIViewController, MKMapViewDelegate, CLLocationManagerDelegate {
#IBOutlet weak var mapView: MKMapView!
// Call the locationManager class
let LocationManager = CLLocationManager()
// CoreData Delegate
let appDelegate = UIApplication.shared.delegate as! AppDelegate
override func viewDidLoad() {
super.viewDidLoad()
// Conform to Delegate Method
self.LocationManager.delegate = self
// Set required accuracy
self.LocationManager.desiredAccuracy = kCLLocationAccuracyBest
// Blue dot
self.mapView.showsUserLocation = true
}
override func didReceiveMemoryWarning() {
super.didReceiveMemoryWarning()
// Dispose of any resources that can be recreated.
}
// check location services active
func locationManager(_ manager: CLLocationManager, didChangeAuthorization status: CLAuthorizationStatus) {
// check location services
switch CLLocationManager.authorizationStatus() {
case .authorizedAlways:
self.LocationManager.startUpdatingLocation()
case .notDetermined:
self.LocationManager.requestAlwaysAuthorization()
case .authorizedWhenInUse, .restricted, .denied:
let alertController = UIAlertController(
title: "Background Location Access Disabled",
message: "In order to work your location settings need to be set to 'Always'.",
preferredStyle: .alert)
let cancelAction = UIAlertAction(title: "Cancel", style: .cancel, handler: nil)
alertController.addAction(cancelAction)
let openAction = UIAlertAction(title: "Open Settings", style: .default) { (action) in
if let url = NSURL(string:UIApplicationOpenSettingsURLString) {
UIApplication.shared.open(url as URL)
}
}
alertController.addAction(openAction)
self.present(alertController, animated: true, completion: nil)
}
}
// Location delegate methods
func locationManager(_ manager: CLLocationManager, didUpdateLocations locations: [CLLocation]) {
print(locations)
// get last location
let location = locations.last
print(location!.coordinate.latitude)
// set region
let region = MKCoordinateRegion(center: location!.coordinate, span: MKCoordinateSpan(latitudeDelta: 0.01, longitudeDelta: 0.01))
// deploy region to map
self.mapView.setRegion(region, animated: true)
// Map to follow the user
self.mapView.setUserTrackingMode(MKUserTrackingMode.follow, animated: true)
// Show compass on map
self.mapView.showsCompass = true
// save the location data to CoreData
//self.save(latitude: location!.coordinate.latitude, longitude: location!.coordinate.longitude)
// end Location updating
self.LocationManager.stopUpdatingLocation()
}
func locationManager(_ manager: CLLocationManager, didFailWithError error: Error) {
print("Errors: " + error.localizedDescription)
}
}
My issue is that func locationManager(_ manager: CLLocationManager, didUpdateLocations locations: [CLLocation] calls itself over and over again (around 3 times on initial load)...
I am using the .last which AFAIK is meant to pull out the last result in that object.. which it probably is, as with breakpoints inserted it after the first 2 prints it only returns 1 lot of results...
After searching high and low, I am hoping I can get a result by asking the question... Thanks!
Console output of my issue:

Answer 1

When you call startUpdatingLocation() the location manager immediately starts the delivering of location data. The first incoming locations may be way off your actual location, so check the horizontalAccuracy and verticalAccuracy attributes and dismiss locations which are too inaccurate.

Answer 2

It looks like you just want to get a one-shot location, if so try this code:
// Use:
// at class level:
// var manager: LocationOneShotManager?
// in viewDidLoad:
// manager = LocationOneShotManager()
// manager!.fetchWithCompletion {location, error in
// // fetch location or an error
// if let loc = location {
// println(location)
// } else if let err = error {
// println(err.localizedDescription)
// }
// self.manager = nil
// }
import UIKit
import CoreLocation
// possible errors
enum OneShotLocationManagerErrors: Int {
case AuthorizationDenied
case AuthorizationNotDetermined
case InvalidLocation
}
class LocationOneShotManager: NSObject, CLLocationManagerDelegate {
// location manager
private var locationManager: CLLocationManager?
// destroy the manager
deinit {
locationManager?.delegate = nil
locationManager = nil
}
typealias LocationClosure = ((location: CLLocation?, error: NSError?)->())
private var didComplete: LocationClosure?
// location manager returned, call didcomplete closure
private func _didComplete(location: CLLocation?, error: NSError?) {
locationManager?.stopUpdatingLocation()
didComplete?(location: location, error: error)
locationManager?.delegate = nil
locationManager = nil
}
// location authorization status changed
func locationManager(manager: CLLocationManager, didChangeAuthorizationStatus status: CLAuthorizationStatus) {
switch status {
case .AuthorizedWhenInUse:
self.locationManager!.startUpdatingLocation()
case .Denied:
_didComplete(nil, error: NSError(domain: self.classForCoder.description(),
code: OneShotLocationManagerErrors.AuthorizationDenied.rawValue,
userInfo: nil))
default:
break
}
}
internal func locationManager(manager: CLLocationManager, didFailWithError error: NSError) {
_didComplete(nil, error: error)
}
internal func locationManager(manager: CLLocationManager, didUpdateLocations locations: [CLLocation]) {
let location = locations[0]
_didComplete(location, error: nil)
}
// ask for location permissions, fetch 1 location, and return
func fetchWithCompletion(completion: LocationClosure) {
// store the completion closure
didComplete = completion
// fire the location manager
locationManager = CLLocationManager()
locationManager!.delegate = self
// check for description key and ask permissions
if (NSBundle.mainBundle().objectForInfoDictionaryKey("NSLocationWhenInUseUsageDescription") != nil) {
locationManager!.requestWhenInUseAuthorization()
} else if (NSBundle.mainBundle().objectForInfoDictionaryKey("NSLocationAlwaysUsageDescription") != nil) {
locationManager!.requestAlwaysAuthorization()
} else {
fatalError("To use location in iOS8 you need to define either NSLocationWhenInUseUsageDescription or NSLocationAlwaysUsageDescription in the app bundle's Info.plist file")
}
}
}