Update MKPointAnnotation object while dragging

Question

I want to know how to update my annotation title while i am dragging it because all the annotation properties are get only.

Code I have try:

func mapView(_ mapView: MKMapView, annotationView view: MKAnnotationView, didChange newState: MKAnnotationViewDragState, fromOldState oldState: MKAnnotationViewDragState) {

    switch (newState) {
    case .starting:
        //view.dragState = .dragging
        print("dragging.....")
    case .ending, .canceling:
        // view.dragState = .none
        let lat = view.annotation?.coordinate.latitude
        let long = view.annotation?.coordinate.longitude
        let coordinates = CLLocationCoordinate2D(latitude: lat!, longitude: long!)
        print(" pin lat \(lat) long \(long)")

        //Error here - title is get only property
        view.annotation?.title = "New Location"

    default: break
    }

}

Answer 1

In the drag method of MKMapViewDelegate, annotation is read only so you can use didSelectAnnotationView method of MKMapViewDelegate because before drag it will call didSelectAnnotationView method, for that declare one selectedAnnotation instance property of type MKPointAnnotation.

var selectedAnnotation: MKPointAnnotation?

Now use this property in didSelectAnnotationView method.

func mapView(mapView: MKMapView, didSelectAnnotationView view: MKAnnotationView) {
    selectedAnnotation = view.annotation as? MKPointAnnotation
}

Now to change the title use this annotation

func mapView(_ mapView: MKMapView, annotationView view: MKAnnotationView, didChange newState: MKAnnotationViewDragState, fromOldState oldState: MKAnnotationViewDragState) {
    switch (newState) {
        case .starting:
            //view.dragState = .dragging
            print("dragging.....")
        case .ending, .canceling:
            // view.dragState = .none
            let lat = view.annotation?.coordinate.latitude
            let long = view.annotation?.coordinate.longitude
            let coordinates = CLLocationCoordinate2D(latitude: lat!, longitude: long!)
            print(" pin lat \(lat) long \(long)")
            self. selectedAnnotation?.title = "New Location"
        default: break
    }

}