How to save the current location coordinate in one ViewController and pass to another ViewController in swift?

Question

I am currently learning swift and I want to find the user's current location in one View Controller (ViewController A) and save it. And later on display the saved location in another View Controller (ViewController B). It can locate and find the current location. When printing it, it shows the coordinate as well. But it cannot be passed to another View Controller. I am not sure if it is an appropriate way to save the coordinate (return a value in function). Here is the code that I work with:

func locationManager(_ manager: CLLocationManager, didUpdateLocations locations: [CLLocation]) -> CLLocation {   

      let currentLocation: CLLocation = locations[0] as CLLocation
      let lat = currentLocation.coordinate.latitude
      let long = currentLocation.coordinate.longitude
      let center = CLLocationCoordinate2D(latitude: currentLocation.coordinate.latitude, longitude: currentLocation.coordinate.longitude)
      let latDelta = 0.05
      let longDelta = 0.05
      let currentLocationSpan:MKCoordinateSpan =
            MKCoordinateSpanMake(latDelta, longDelta)
      let region = MKCoordinateRegion(center: center, span: currentLocationSpan)

      myMapView.setRegion(region, animated: true)

      let myAnnotation: MKPointAnnotation = MKPointAnnotation()
      myAnnotation.coordinate = CLLocationCoordinate2D(latitude: currentLocation.coordinate.latitude, longitude: currentLocation.coordinate.longitude)
      myAnnotation.title = "Current Location"
      myMapView.addAnnotation(myAnnotation)

      print("The latitude is \(lat)")
      print("The longitude is\(long)")
      print(currentLocation)

     return currentLocation 
 }

And in View Controller B, the code is like that and it does not know what currentLocation is:

class ViewControllerB: ViewControllerA {

   override func viewDidLoad() {

     super.viewDidLoad()

     let center = CLLocationCoordinate2D(latitude:currentLocation.coordinate.latitude, longitude:currentLocation.coordinate.longitude)
}

Does anyone know how to fix it? Millions thanks!

how are you presenting ViewControllerB? Also, why does ViewControllerB subclass ViewControllerA? — Andy Obusek, Apr 23 '18 at 13:23

score 0 · Answer 1 · answered Apr 23 '18 at 13:22

Create a property on ViewControllerB for the CLLocation and set the value at the appropriate time (based on how your view controllers are connected):

class ViewControllerB: ViewControllerA {

 let currentLocation: CLLocation? = nil

 override func viewDidLoad() {

    super.viewDidLoad()
    guard let currentLocation = currentLocation else { return }
    let center = CLLocationCoordinate2D(latitude:currentLocation.coordinate.latitude, longitude:currentLocation.coordinate.longitude)
}

And then, somewhere in ViewControllerA

viewControllerB.currentLocation = currentLocation

How to save the current location coordinate in one ViewController and pass to another ViewController in swift?

1 Answers1