Error in MKCoordinateSpan, says to run before the self is available

Question

I was integrating my app with a map, and when I declare a variable span with MKCoordinateSpan type, it gives me this error:

Cannot use instance member 'latDelta' within property initializer; property initializers run before 'self' is available

Also when I write other types such as: CLLocationCoordinate2D or MKCoordinateRegion it still says me that the variable within the property initializer cannot be used.

I don't know what the problem is, any help would be appreciated!

Here's my code:

import UIKit
import MapKit
class ViewController: UIViewController, MKMapViewDelegate {

    @IBOutlet var map: MKMapView!

    let latitude: CLLocationDegrees = 42.8
    let longitude: CLLocationDegrees = 74.6
    let latDelta: CLLocationDegrees = 0.05
    let lonDelta: CLLocationDegrees = 0.05

    let span: MKCoordinateSpan = MKCoordinateSpan(latitudeDelta: latDelta, longitudeDelta: lonDelta)

Answer 1

That is not correct way to initialise values. but you can do that in any other class method. Check below code:

class ViewController: UIViewController, MKMapViewDelegate {

    @IBOutlet var map: MKMapView!

    let latitude: CLLocationDegrees = 42.8
    let longitude: CLLocationDegrees = 74.6
    let latDelta: CLLocationDegrees = 0.05
    let lonDelta: CLLocationDegrees = 0.05

    //Declare it here
    var span: MKCoordinateSpan?

    override func viewDidLoad() {
        super.viewDidLoad()

        //Assign values here in method
        span = MKCoordinateSpan(latitudeDelta: latDelta, longitudeDelta: lonDelta)
    }

}