Strange behaviour in showing annotations images on map using data coming from Firebase. SWIFT 4.1 - ios

Question

The strange behaviour is that when I add a new annotation, either tapped or user location, it gets displayed with the right chosen icon. When MapVC load for the first time, the posts retrieved from Firebase have all the same icon, ( the icon name of the latest one posted. If, after posting a new one, I exit mapViewVc to the menuVC and re enter mapViewVC than every icon is displaying the same icon again, now being my previously posted one.
a Few times it happened the the icons were two different icons, randomly chosen.
I don't understand why the coordinates are taken right but the image is not.
The app flow is:
I have a mapView vc where I can either double tap on screen and get coordinate or code user location coordinate via a button and then get to an chooseIconVc where I have all available icons to choose for the annotation. Once I select one, the icon name get passed back in in mapViewVC in unwindHere() that stores icon name into a variable and coordinates into another. In postAlertNotification those variables get posted to Firebase.
In displayAlerts() the data from Firebase gets stored into variables to initialise an annotation and gets added to mapView.
chosen icon:
#IBAction func unwindHere(sender:UIStoryboardSegue) { // data coming back
if let sourceViewController = sender.source as? IconsViewController {
alertNotificationType = sourceViewController.dataPassed
if tapCounter > 0 {
alertNotificationLatitude = String(describing: alertCoordinates.latitude)
alertNotificationLongitude = String(describing: alertCoordinates.longitude)
postAlertNotification() // post new notification to Firebase
} else {
alertCoordinates = self.trackingCoordinates
alertNotificationLatitude = String(describing: self.trackingCoordinates!.latitude)
alertNotificationLongitude = String(describing: self.trackingCoordinates!.longitude)
postAlertNotification() // post new notification to Firebase
}
}
}
than post:
func postAlertNotification() {
// to set next notification id as the position it will have in array ( because first position is 0 ) we use the array.count as value
let latitude = alertNotificationLatitude
let longitude = alertNotificationLongitude
let alertType = alertNotificationType
let post: [String:String] = [//"Date" : date as! String,
//"Time" : time as! String,
"Latitude" : latitude as! String,
"Longitude" : longitude as! String,
"Description" : alertType as! String]
var ref: DatabaseReference!
ref = Database.database().reference()
ref.child("Community").child("Alert Notifications").childByAutoId().setValue(post)
}
retrieve and display:
func displayAlerts() {
ref = Database.database().reference()
databaseHandle = ref?.child("Community").child("Alert Notifications").observe(.childAdded, with: { (snapshot) in
// defer { self.dummyFunctionToFoolFirebaseObservers() }
guard let data = snapshot.value as? [String:String] else { return }
guard let firebaseKey = snapshot.key as? String else { return }
// let date = data!["Date"]
// let time = data!["Time"]
let dataLatitude = data["Latitude"]!
let dataLongitude = data["Longitude"]!
self.alertIconToDisplay = data["Description"]!
let doubledLatitude = Double(dataLatitude)
let doubledLongitude = Double(dataLongitude)
let recombinedCoordinate = CLLocationCoordinate2D(latitude: doubledLatitude!, longitude: doubledLongitude!)
print("Firebase post retrieved !")
print("Longitude Actual DataKey is \(String(describing: firebaseKey))")
print("fir long \((snapshot.value!, snapshot.key))")
self.userAlertAnnotation = UserAlert(type: self.alertIconToDisplay!, coordinate: recombinedCoordinate, firebaseKey: firebaseKey)
self.mapView.addAnnotation(self.userAlertAnnotation)
})
}
and
func mapView(_ mapView: MKMapView, viewFor annotation: MKAnnotation) -> MKAnnotationView? {
let annotationView = MKAnnotationView(annotation: userAlertAnnotation, reuseIdentifier: "") // CHANGE FOR NEW ANNOTATION : FULL DATA
//added if statement for displaying user location blue dot
if annotation is MKUserLocation{
return nil
} else {
annotationView.image = UIImage(named: alertIconToDisplay!) // choose the image to load
let transform = CGAffineTransform(scaleX: 0.27, y: 0.27)
annotationView.transform = transform
return annotationView
}
}
the variables declarations :
var alertIconToDisplay: String?
var userAlertAnnotation: UserAlert!
var alertNotificationType: String?
var alertNotificationLatitude: String?
var alertNotificationLongitude: String?
UPDATE:
annotation cLass:
import MapKit
class UserAlert: NSObject , MKAnnotation {
var type: String?
var firebaseKey: String?
var coordinate = CLLocationCoordinate2D()
var image: UIImage?
override init() {
}
init(type:String, coordinate:CLLocationCoordinate2D, firebaseKey: String) {
self.type = type
self.firebaseKey = firebaseKey
self.coordinate = coordinate
}
}

Answer 1

After understanding where the problem I was explained how to changed the displayAlert() into
func displayAlerts() { // rajish version
ref = Database.database().reference()
databaseHandle = ref?.child("Community").child("Alert Notifications").observe(.childAdded, with: { (snapshot) in
// defer { self.dummyFunctionToFoolFirebaseObservers() }
guard let data = snapshot.value as? [String:String] else { return }
guard let firebaseKey = snapshot.key as? String else { return }
// let date = data!["Date"]
// let time = data!["Time"]
let dataLatitude = data["Latitude"]!
let dataLongitude = data["Longitude"]!
let type = data["Description"]!
let id = Int(data["Id"]!)
let doubledLatitude = Double(dataLatitude)
let doubledLongitude = Double(dataLongitude)
let recombinedCoordinate = CLLocationCoordinate2D(latitude: doubledLatitude!, longitude: doubledLongitude!)
print("Firebase post retrieved !")
print("Longitude Actual DataKey is \(String(describing: firebaseKey))")
print("fir long \((snapshot.value!, snapshot.key))")
var userAlertAnnotation = UserAlert(type: type, coordinate: recombinedCoordinate, firebaseKey: firebaseKey, title: type,id: id!)
self.userAlertNotificationArray.append(userAlertAnnotation) // array of notifications coming from Firebase
print("user alert array after append from Firebase is : \(self.userAlertNotificationArray)")
self.alertNotificationArray.append(recombinedCoordinate) // array for checkig alerts on route
self.mapView.addAnnotation(userAlertAnnotation)
})
}
and the mapView to:
func mapView(_ mapView: MKMapView, viewFor annotation: MKAnnotation) -> MKAnnotationView? { // rajish version
let annotationView = MKAnnotationView(annotation: annotation, reuseIdentifier: "")
if annotation is MKUserLocation{
return nil
} else {
print(annotation.coordinate)
annotationView.image = UIImage(named:(annotationView.annotation?.title)! ?? "")
// annotationView.canShowCallout = true
let transform = CGAffineTransform(scaleX: 0.27, y: 0.27)
annotationView.transform = transform
return annotationView
}
}
that solved it.