Swift delegate protocol not updating with locationManager - ios

Question

I have 2 views which the childView communicates with the parentView. I am using Google maps SDK to track a users location however if I startUpdatingLocation() using a button, the protocol does not work however if I initiate startUpdatingLocation() as soon as the app loads it works fine. Below are my Two controller files.
I am simply trying to display the location in a label but not sure why the protocol is not working after button click.
Child:
import Foundation
import UIKit
protocol LocationUpdateDelegate{
func delegateUserLocation(mapChildController:MapChildController, userLocation: String)
}
class MapChildController: UIViewController, CLLocationManagerDelegate
{
#IBOutlet weak var mapView: GMSMapView!
let locationManager = CLLocationManager()
var didFindMyLocation = false
var myLocations:[String] = []
var alreadyUpdatedLocation = false
var locationDelegate:LocationUpdateDelegate?
override func viewDidLoad() {
super.viewDidLoad()
// Do any additional setup after loading the view, typically from a nib.
var camera = GMSCameraPosition.cameraWithLatitude(-33.86, longitude: 151.20, zoom: 15, bearing: 0, viewingAngle: 45)
var mapView = GMSMapView.mapWithFrame(CGRectZero, camera: camera)
mapView.myLocationEnabled = true
self.view = mapView
if NSProcessInfo().isOperatingSystemAtLeastVersion(NSOperatingSystemVersion(majorVersion: 8, minorVersion: 0, patchVersion: 0)) {
println("iOS >= 8.0.0")
locationManager.requestWhenInUseAuthorization()
}
mapView.addObserver(self, forKeyPath: "myLocation", options: NSKeyValueObservingOptions.New, context: nil)
}
override func didReceiveMemoryWarning() {
super.didReceiveMemoryWarning()
// Dispose of any resources that can be recreated.
}
override func observeValueForKeyPath(keyPath: String, ofObject object: AnyObject, change: [NSObject : AnyObject], context: UnsafeMutablePointer<Void>) {
if !didFindMyLocation {
let myLocation: CLLocation = change[NSKeyValueChangeNewKey] as! CLLocation
var mapView = self.view as! GMSMapView
mapView.camera = GMSCameraPosition.cameraWithTarget(myLocation.coordinate, zoom: 15.0)
mapView.settings.myLocationButton = true
didFindMyLocation = true
}
}
func locationManager(manager:CLLocationManager, didUpdateLocations locations:[AnyObject]) {
var locValue:CLLocationCoordinate2D = manager.location.coordinate
myLocations.append("\(locValue.latitude)/\(locValue.longitude)")
self.locationDelegate?.delegateUserLocation(self, userLocation: "From child")
println("Child location: \(locValue.latitude)/\(locValue.longitude)")
}
func trackingToggle()
{
if !alreadyUpdatedLocation
{
locationManager.delegate = self
locationManager.distanceFilter = kCLDistanceFilterNone
locationManager.desiredAccuracy = kCLLocationAccuracyBest
locationManager.startUpdatingLocation()
println("Tracking started")
alreadyUpdatedLocation = true
}
else
{
locationManager.stopUpdatingLocation()
println("Tracking stopped")
alreadyUpdatedLocation = false
}
}
}
Parent:
import UIKit
struct Constants {
static let embedSegue = "embedSegue"
}
class MapMainController: UIViewController, LocationUpdateDelegate
{
let mapChild = MapChildController()
var alreadyUpdatedLocation = false;
#IBOutlet weak var startTrackingButton: UIButton!
#IBOutlet weak var MapStatsView: UIView!
#IBOutlet weak var txtUserLocation: UILabel!
override func viewDidLoad() {
super.viewDidLoad()
}
override func didReceiveMemoryWarning() {
super.didReceiveMemoryWarning()
// Dispose of any resources that can be recreated.
}
override func prepareForSegue(segue: UIStoryboardSegue, sender: AnyObject?) {
if segue.identifier == Constants.embedSegue {
let mapChildController = segue.destinationViewController as! MapChildController
mapChildController.locationDelegate = self
}
}
func delegateUserLocation(mapChildController: MapChildController, userLocation: String) {
println("Parent location: \(userLocation)");
txtUserLocation.text = userLocation
}
#IBAction func startTrackingTapped(sender: UIButton) {
mapChild.trackingToggle();
if !alreadyUpdatedLocation
{
alreadyUpdatedLocation = true
startTrackingButton.setTitle("Stop Tracking", forState: UIControlState.Normal)
}
else
{
alreadyUpdatedLocation = false
startTrackingButton.setTitle("Start Tracking", forState: UIControlState.Normal)
}
}
}

Answer 1

You are setting the mapChildController to self just before you segue to another view:
override func prepareForSegue(segue: UIStoryboardSegue, sender: AnyObject?) {
if segue.identifier == Constants.embedSegue {
let mapChildController = segue.destinationViewController as! MapChildController
mapChildController.locationDelegate = self
After you just set the delegate to self your viewController went out of scope, now your delegate is nil again and will never be called.
You need to set the delegate in viewDidLoad