Deleting wrong displayed annotation when deleting selected MKAnnotation from map SWIFT 4.1

Question

I have an userAlertAnnotationArray: [MKAnnotations] that gets entries from data retrieved from Firebase. The deleting part is working perfectly with posts in Firebase and entries in the array, but it fails when deleting the selected MKAnnotation from the map. It deletes from the map the wrong Annotation. If I exit mapVC to the menuVC and reenter mapVC that the right annotation is gone.

After a few tries, I noticed it because I get an out of range error only if i re-enter mapVC. I don't want to call the viewDiedLoad() function to refresh the view because that would be a new read per entry from Firebase every time an annotation gets deleted.

Can you see where I made a coding mistake? The updating showed annotation that fails, userAlertAnnotationArray gets the annotation removed. Please let me know if you need to see more code or other functions. Thanks in advance. This is the didSelect function:

    func mapView(_ mapView: MKMapView, didSelect view: MKAnnotationView) {


        let alertController = UIAlertController(title: "User Alert", message: "Delete selected Alert?", preferredStyle: .alert)

        // Create OK button
        let OKAction = UIAlertAction(title: "OK", style: .default) { (action:UIAlertAction!) in

            // Code in this block will trigger when OK button tapped.

            var selectedAnnotation = view.annotation
            if let annotation = view.annotation as? UserAlert {
                let key = annotation.firebaseKey

                let index = (self.mapView.annotations as NSArray).index(of: annotation)
                self.userAlertNotificationArray.remove(at: index)
                print(" New alert array after deliting is : \(self.userAlertNotificationArray)" )

                print("post to remove key is: \(String(describing: key!))")

                self.ref?.child("Community").child("Alert Notifications").child("\(String(describing: annotation.firebaseKey!))").removeValue()


                mapView.removeAnnotations(mapView.annotations)
                mapView.addAnnotations(self.userAlertNotificationArray)
//                self.viewDidLoad()
            }
            //            print("Ok button tapped")
        }
        alertController.addAction(OKAction)
        // Create Cancel button
        let cancelAction = UIAlertAction(title: "Cancel", style: .cancel) { (action:UIAlertAction!) in
            print("Cancel button tapped");
        }
        alertController.addAction(cancelAction)
        // Present Dialog message
        self.present(alertController, animated: true, completion:nil)
    }

score 1 · Accepted Answer · answered Aug 11 '18 at 14:04

1

The problem is that you are getting the index from the annotations array on the map view and not from your array; they might be different, for example if the map is displaying the user location that is another annotation.

Try replacing your declaration of index with this:

let index = (self.userAlertNotificationArray as NSArray).index(of: annotation)

answered Aug 11 '18 at 14:04

vicegax

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@ zero. Yeah sure! that was my mistake, thanks for the explanation , it actually was giving me back an array count of 1 when I did delete all annotations. makes perfect sense now. Thank you so much. – Vincenzo Aug 11 '18 at 14:11

Deleting wrong displayed annotation when deleting selected MKAnnotation from map SWIFT 4.1

1 Answers1