How do you add a button to MapKit CallOuts Swift 3 - ios

Question

I am trying to add a button to my Callouts so that I can transition to another view controller. The callouts however, won't show the accessory view and I am unsure why. I grab some data from firebase and feed it into the proper arrays, then I have the annotation posted with the call out. I am not sure why the button is not showing up.
This code takes place within ViewDidLoad(){...}
bookRef.observeSingleEvent(of: .value, with: {snapshot in
if let userDict = snapshot.value as? [String:AnyObject]{
for each in userDict as [String:AnyObject]{
let bookLats = each.value["bookLat"] as! String
let bookLngs = each.value["bookLng"] as! String
let bookTitle = each.value["title"] as! String
let Author = each.value["Author"] as! String
let Comment = each.value["Comment"] as! String
let Genre = each.value["Genre"] as! String
let User = each.value["User"] as! String
let bookPhoto = each.value["bookPhoto"] as! String
let userID = each.value["userID"] as! String
let userLocation = each.value["userLocation"] as! String
let bookRate = each.value["bookRating"] as! String
let userToBePushed = each.value["pushingID"] as! String
self.bookLatArrayDouble.append((bookLats as NSString).doubleValue)
self.bookLngArrayDouble.append((bookLngs as NSString).doubleValue)
self.bookTitlesArray.append(bookTitle)
}
}
for i in 0...(self.bookLatArrayDouble.count-1){
let locationCoordinates = CLLocationCoordinate2D(latitude: self.bookLatArrayDouble[i], longitude: self.bookLngArrayDouble[i])
var point = BookAnnotation(coordinate: locationCoordinates)
point.title = self.bookTitlesArray[i]
self.Map.addAnnotation(point)
}
I also used this function.
func mapView(_ mapView: MKMapView, viewFor annotation: MKAnnotation) -> MKAnnotationView? {
// If annotation is not of type RestaurantAnnotation (MKUserLocation types for instance), return nil
var annotationView = self.Map.dequeueReusableAnnotationView(withIdentifier: "Pin")
if annotationView == nil{
annotationView = MKPinAnnotationView(annotation: annotation, reuseIdentifier: "Pin")
annotationView?.canShowCallout = true
annotationView?.rightCalloutAccessoryView = UIButton(type: .detailDisclosure)
}else{
annotationView?.annotation = annotation
}
return annotationView
}
Edit: imgage requested

Answer 1

I made a very silly of error... I forgot to put Map.delegate.self so it makes sense that the function was never actually called. The button now shows Thank you all for your help!

Answer 2

Your flow control is weird
why just when if annotationView == nil then you add CalloutAccessoryView ??
try this code:
if annotationView == nil{
annotationView = MKPinAnnotationView(annotation: annotation, reuseIdentifier: "Pin")
}else{
annotationView?.annotation = annotation
}
annotationView?.canShowCallout = true
annotationView?.rightCalloutAccessoryView = UIButton(type: .detailDisclosure)
And I'm guess that self.Map.dequeueReusableAnnotationView(withIdentifier: "Pin") may return nil because I don't see your code for that
Return Value
An annotation view with the specified identifier, or nil if no such object exists in the reuse queue.
but when it != nil. you need to add Accessory into it too