User location won't come up in simulator in Xcode - ios

Question

I'm new to app development and I'm trying to get the user location to come up in the simulator but I keep getting the Use of unresolved identifier error. I have looked at other questions, which are very specific to their own projects, and have tried to approach my own app in a similar way but to not avail. Any help, por favor? Here's my code, and a link to a screenshot of Xcode.
import UIKit
import MapKit
import CoreLocation
class SecondViewController: UIViewController, CLLocationManagerDelegate {
//Map
#IBOutlet weak var map: MKMapView!
let manager = CLLocationManager()
func locationManager(_ manager: CLLocationManager, didUpdateLocations locations: [CLLocation])
{ let location = locations[0]
let span:MKCoordinateSpan = MKCoordinateSpanMake(0.01, 0.01)
let myLocation:CLLocationCoordinate2D = CLLocationCoordinate2DMake(location.coordinate.latitude, location.coordinate.longitude)
let region:MKCoordinateRegion = MKCoordinateRegionMake(myLocation, span)
self.map.showsUserLocation = true
}
override func viewDidLoad()
{
super.viewDidLoad()
manager.delegate = self
manager.desiredAccuracy = kCLLocationAccuracyBest
manager.requestWhenInUseAuthorization()
manager.startUpdatingLocation()
//This is where I get an error
map.setRegion(region, animated: true)**
}
Error: Use of unresolved identifier

Answer 1

Your let region:MKCoordinateRegion is a local identifier inside your delegate method:
func locationManager(_:didUpdateLocations) {...}
This is why you are getting Use of unresolved identifier. Make this identifier accessible throughout the class, the error will be gone. Like:
class SecondViewController: UIViewController, CLLocationManagerDelegate {
//Map
#IBOutlet weak var map: MKMapView!
var region = MKCoordinateRegion()
.......
.......
}
N.B: But this won't let you see anything in the map. Best way to see any output from your MapView is to put map.setRegion(region, animated: true) inside your delegate method:
func locationManager(_ manager: CLLocationManager, didUpdateLocations locations: [CLLocation]) {
let location = locations.first
let span = MKCoordinateSpanMake(0.01, 0.01)
let myLocation = CLLocationCoordinate2DMake((location?.coordinate.latitude)!, (location?.coordinate.longitude)!)
region = MKCoordinateRegionMake(myLocation, span)
map.setRegion(region, animated: true)
}

Answer 2

Use MKCoordinateRegion instance before viewdidload method
You can follow below code for reference.
class Test: UIViewController {
var region = MKCoordinateRegion()
override func viewDidLoad() {
super.viewDidLoad()
region = MKCoordinateRegionMake(myLocation, span)
}
}

Answer 3

You are getting Error because
the variable region inside viewDidLoad() method do not have access of region variable inside
viewDidLoad() method
//This is where I get an error
map.setRegion(region, animated: true)**
Solution :
Make region variable global to class so that that can be accessed from anywhere you want to.
Instead of this line inside func locationManager
let region:MKCoordinateRegion = MKCoordinateRegionMake(myLocation,span)
Use
self.region = MKCoordinateRegionMake(myLocation,span)
Here is complete code That you can use.
import UIKit
import MapKit
import CoreLocation
class SecondViewController: UIViewController, CLLocationManagerDelegate {
//Map
#IBOutlet weak var map: MKMapView!
//global variable
var region:MKCoordinateRegion = MKCoordinateRegion()
let manager = CLLocationManager()
func locationManager(_ manager: CLLocationManager, didUpdateLocations locations: [CLLocation])
{ let location = locations[0]
let span:MKCoordinateSpan = MKCoordinateSpanMake(0.01, 0.01)
let myLocation:CLLocationCoordinate2D = CLLocationCoordinate2DMake(location.coordinate.latitude, location.coordinate.longitude)
self.region = MKCoordinateRegionMake(myLocation, span)
self.map.showsUserLocation = true
}
override func viewDidLoad()
{
super.viewDidLoad()
manager.delegate = self
manager.desiredAccuracy = kCLLocationAccuracyBest
manager.requestWhenInUseAuthorization()
manager.startUpdatingLocation()
//This is where I get an error
map.setRegion(region, animated: true)**
}
//
override func didReceiveMemoryWarning() {
super.didReceiveMemoryWarning()
// Dispose of any resources that can be recreated.
}
}
And more important if you are using simulator then you have to enable location simulation.