Problem with delegates removing annotation - swift

Question

I have two screens. The first one (firstViewController) has a mapView with a UITapGestureRecognizer. When the user taps the screen, an annotations is added to the map and the second screen (secondViewController) is presented.
When the user dismisses the secondViewController and comes back to the first one, the annotation should be removed. I know I have to use delegation, but I just can't make it to work.
This is the code I have now:
class firstViewController: UIViewController, AnnotationDelegate {
let mapView = MKMapView()
var temporaryPinArray = [MKPointAnnotation]()
override func viewDidLoad() {
super.viewDidLoad()
view.addSubview(mapView
let gesture = UITapGestureRecognizer(target: self, action: #selector(handleTap(_:)))
mapView.addGestureRecognizer(gesture)
secondVC.annotationDelegate = self
}
override func viewDidLayoutSubviews() {
super.viewDidLayoutSubviews()
mapView.frame = view.bounds
}
#objc func handleTap(_ gestureReconizer: UILongPressGestureRecognizer) {
let location = gestureReconizer.location(in: mapView)
let coordinates = mapView.convert(location, toCoordinateFrom: mapView)
mapView.removeAnnotations(mapView.annotations)
let pin = MKPointAnnotation()
pin.coordinate = coordinates
temporaryPinArray.removeAll()
temporaryPinArray.append(pin)
mapView.addAnnotations(temporaryPinArray)
// Present secondViewController
let secondVC = SecondViewController()
panel.set(contentViewController: secondVC)
panel.addPanel(toParent: self)
}
func didRemoveAnnotation(annotation: MKPointAnnotation) {
mapView.removeAnnotation(annotation)
}
}
Second View Controller
protocol AnnotationDelegate {
func didRemoveAnnotation(annotation: [MKPointAnnotation])
}
class SecondViewController: UIViewController {
var annotationDelegate: AnnotationDelegate!
let mainVC = firstViewController()
let closeButton: UIButton = {
let button = UIButton()
button.backgroundColor = .grey
button.layer.cornerRadius = 15
return button
}()
override func viewDidLoad() {
super.viewDidLoad()
view.addSubview(closeButton)
closeButton.addTarget(self, action: #selector(dismissPanel), for: .touchUpInside)
}
override func viewDidLayoutSubviews() {
super.viewDidLayoutSubviews()
closeButton.frame = CGRect(x: view.frame.width-50, y: 10, width: 30, height: 30)
}
#objc func dismissPanel() {
self.dismiss(animated: true, completion: nil)
annotationDelegate.didRemoveAnnotation(annotation: mainVC.temporaryPinArray)
}
}
Thank you so much for your help!

Answer 1

You created a new instance of firstViewController inside SecondViewController. This instance is unrelated to the actual first one:
let mainVC = firstViewController()
This means that temporaryPinArray is different as well. So instead of passing in this unrelated array...
#objc func dismissPanel() {
self.dismiss(animated: true, completion: nil)
annotationDelegate.didRemoveAnnotation(annotation: mainVC.temporaryPinArray)
}
Just change the function to take no parameters instead:
protocol AnnotationDelegate {
func didRemoveAnnotation() /// no parameters
}
#objc func dismissPanel() {
self.dismiss(animated: true, completion: nil)
annotationDelegate.didRemoveAnnotation() /// no parameters
}
And inside firstViewController's didRemoveAnnotation, reference the actual temporaryPinArray.
func didRemoveAnnotation() {
mapView.removeAnnotations(temporaryPinArray) /// the current array
}