CLLocationManager: Unexpectedly Found Nil While Unwrapping an Optional Value

Question

Here's my code in ViewController.swift:

import UIKit
import Alamofire
import SwiftyJSON
import MapKit
import CoreLocation
import TwitterKit

class ViewController: UIViewController, MKMapViewDelegate, CLLocationManagerDelegate {

    @IBOutlet weak var myMap: MKMapView!
    @IBOutlet weak var counterLabel: UILabel!

    var manager = CLLocationManager()

    override func viewDidLoad() {
        super.viewDidLoad()

        // Do any additional setup after loading the view, typically from a nib.

        //calling CLLocation
        manager.delegate = self
        manager.desiredAccuracy = kCLLocationAccuracyBest
        manager.requestWhenInUseAuthorization()
        manager.startUpdatingLocation()

        //map region
        let locationZoom = self.manager.location
        var latitude: Double = locationZoom.coordinate.latitude
        var longitude: Double = locationZoom.coordinate.longitude
        var centerLatitude: CLLocationDegrees = locationZoom.coordinate.latitude
        var centerLongitude: CLLocationDegrees = locationZoom.coordinate.longitude
        var latDelta: CLLocationDegrees = 0.03
        var longDelta: CLLocationDegrees = 0.03
        var span: MKCoordinateSpan = MKCoordinateSpanMake(latDelta, longDelta)
        var location: CLLocationCoordinate2D = CLLocationCoordinate2DMake(centerLatitude, centerLongitude)
        var region: MKCoordinateRegion = MKCoordinateRegionMake(location, span) // this creates a map region with the center
        myMap.setRegion(region, animated: true)
    }

    @IBAction func zoom(sender: AnyObject) {


        let locationZoom = self.manager.location

        var latitude: Double = locationZoom.coordinate.latitude
        var longitude: Double = locationZoom.coordinate.longitude
        var centerLatitude:CLLocationDegrees = locationZoom.coordinate.latitude
        var centerLongitude: CLLocationDegrees = locationZoom.coordinate.longitude
        var latDelta:CLLocationDegrees = 0.03
        var longDelta:CLLocationDegrees = 0.03
        var span:MKCoordinateSpan = MKCoordinateSpanMake(latDelta, longDelta)
        var location:CLLocationCoordinate2D = CLLocationCoordinate2DMake(centerLatitude, centerLongitude)
        var region:MKCoordinateRegion = MKCoordinateRegionMake(location, span) // this creates a map region with the center
        myMap.setRegion(region, animated: true)
    }
}

Now, the error is described as thus:

fatal error: unexpectedly found nil while unwrapping an Optional value

Thread 1 is pointing towards this being the issue:

var latitude: Double = locationZoom.coordinate.latitude

However, when testing this on the simulator, I have also found the issue to occur with the longitude variable. Still, I do not understand why the values for both longitude and latitude are set to "nil." I have set up CLLocationManager correctly, made sure to modify info.plist as necessary to include NSLocationWhenInUseUsageDescription and NSLocationAlwaysUsageDescription, etc. What's going on, and how do I correct this issue?

Answer 1

This happens because when your view loads it has not received any location update. Implement DidUpdateLocations and access location info there. if you need reference you can look DidUpdateLocations

func locationManager(manager: CLLocationManager!, didUpdateLocations locations: [AnyObject]!) {

    let locationZoom = locations.last as! CLLocation
    let latitude: Double = locationZoom.coordinate.latitude
    let longitude: Double = locationZoom.coordinate.longitude
    println(latitude)
    println(longitude)
}