App crashes when dismissing view controller - ios

Question

I've a simple ViewController that displays my current location coordinates.
Everything is working properly, but when I dismiss the ViewController, the app crashes without any specific error log.
The class code goes like this:
import UIKit
class LocationViewController: UIViewController, CLLocationManagerDelegate, MKMapViewDelegate, UIPopoverPresentationControllerDelegate {
// General objects
#IBOutlet var closeButton: UIButton!
#IBOutlet var latitudeLabel: UILabel!
#IBOutlet var longitudeLabel: UILabel!
#IBOutlet var infoButton: UIButton!
// Global variables
var location: CLLocationManager? = CLLocationManager()
var geocoder = CLGeocoder();
var placemark = CLPlacemark();
var hasPin: Bool = false;
override func viewDidLoad() {
super.viewDidLoad()
// Ask for Authorisation from the User.
location?.requestAlwaysAuthorization();
// For use in foreground
location?.requestWhenInUseAuthorization();
getCurrentLocation();
}
override func didReceiveMemoryWarning() {
super.didReceiveMemoryWarning()
// Dispose of any resources that can be recreated.
}
#IBAction func closeButton(_ sender: AnyObject) {
self.dismiss(animated: true, completion: {
print("dismissing locationViewController");
self.location = nil;
});
}
#IBAction func infoButton(_ sender: AnyObject) {
// TODO
}
// MARK: - General functions
func getCurrentLocation() -> Void {
if (CLLocationManager.locationServicesEnabled()) {
location?.delegate = self;
location?.desiredAccuracy = kCLLocationAccuracyBest;
location?.startUpdatingLocation();
}
}
// MARK: - CLLocationManagerDelegate
func locationManager(_ manager: CLLocationManager, didFailWithError error: Error) {
print("ERROR = \(error)");
}
func locationManager(_ manager: CLLocationManager, didUpdateLocations locations: [CLLocation]) {
// Gets the user coordinates
let locValue:CLLocationCoordinate2D = manager.location!.coordinate;
USER_LATITUDE = locValue.latitude;
USER_LONGITUDE = locValue.longitude;
longitudeLabel.text = "\(USER_LONGITUDE)";
latitudeLabel.text = "\(USER_LATITUDE)";
location?.stopUpdatingLocation()
}
Does anyone have any clue why this happens?
No error log is prompted that's what makes me even more confused.
First I thought I had to set the location variable to be optional and then set it to nil when I dismiss the VC but the crash is still happening.
Crashlytics says that the App crashes inside the LocationViewController line 0 , which is in fact weird.
I call this ViewController, from a button click inside another VC like this:
#IBAction func locationButton(_ sender: AnyObject) {
let storyboard = UIStoryboard(name: "Main", bundle: nil);
let viewController = storyboard.instantiateViewController(withIdentifier: "locationVC");
self.present(viewController, animated: true, completion: nil);
}
I'm using Swift3 with the latest Xcode Beta Version on iOS 10.
Thanks

Answer 1

Replace this:
var location: CLLocationManager? = CLLocationManager()
With this:
let location = CLLocationManager()
Change all code as necessary (this is no longer an Optional so there is nothing to unwrap) and delete the line that tries to set it to nil.
If you are worried that the location manager might be trying to get your location when you dismiss, then implement viewWillDisappear and tell it to stop updating.

Answer 2

You need to add the privacy entry in Info.plist and also request authorization to use location services. A good overview can be found here: http://nevan.net/2014/09/core-location-manager-changes-in-ios-8/