Don't re-add mapview after is loaded in viewdidload - ios

Question

I have created function caricamappa() to loading map view with my mapbox map, and into Custompointannotation there is a control for add and remove annotation with Bool control, with a button i want to caricamappa() add and remove annotation with force Bool and its work but i don't want to re-add subview(mapview) into my app, is it possible to refresh a view without adding another and hide/show annotation? thanks
func carica_mappa() {
// Fill in the next line with your style URL from Mapbox Studio.
let styleURL = NSURL(string: "mapbox:***")
let mapView = MGLMapView(frame: view.bounds,
styleURL: styleURL as URL?)
mapView.autoresizingMask = [.flexibleWidth, .flexibleHeight]
// Set the map’s center coordinate and zoom level.
mapView.setCenter(CLLocationCoordinate2D(latitude: 44.370417,
longitude: 7.411713),
zoomLevel: 13, animated: false)
view.addSubview(mapView)
mapView.userTrackingMode = .followWithHeading
// Set the delegate property of our map view to `self` after instantiating it.
mapView.delegate = self
let uno = CustomPointAnnotation(coordinate: CLLocationCoordinate2DMake(44.376362, 7.396907),
title: "**",
subtitle: "**",
controllo: visible)
// Set the custom `image` and `reuseIdentifier` properties, later used in the `mapView:imageForAnnotation:` delegate method.
uno.reuseIdentifier = "montagna"
uno.image = UIImage(named: "montagna")
if uno.controllo == true {
mapView.addAnnotation(uno)
}
else {
mapView.removeAnnotation(uno)
}
}
func mapView(_ mapView: MGLMapView, imageFor annotation: MGLAnnotation) -> MGLAnnotationImage? {
if let point = annotation as? CustomPointAnnotation,
let image = point.image,
let reuseIdentifier = point.reuseIdentifier {
if let annotationImage = mapView.dequeueReusableAnnotationImage(withIdentifier: reuseIdentifier) {
// The annotatation image has already been cached, just reuse it.
return annotationImage
} else {
// Create a new annotation image.
return MGLAnnotationImage(image: image, reuseIdentifier: reuseIdentifier)
}
}
// Fallback to the default marker image.
return nil
}
func mapView(_ mapView: MGLMapView, annotationCanShowCallout annotation: MGLAnnotation) -> Bool {
// Always allow callouts to popup when annotations are tapped.
return true
}
override func viewDidLoad() {
super.viewDidLoad()
carica_mappa()
}

Answer 1

My advice is to split the code to setup the map and the one to add the CustomAnnotationView. CaricaMappa() should only be used to add the map to its superview and called in viewDidLoad(). The code to setup the CustomAnnotation should be in its own method and you can call it on button tap. So you would have something like:
func carica_mappa() {
// Fill in the next line with your style URL from Mapbox Studio.
let styleURL = NSURL(string: "mapbox:***")
let mapView = MGLMapView(frame: view.bounds,
styleURL: styleURL as URL?)
mapView.autoresizingMask = [.flexibleWidth, .flexibleHeight]
// Set the map’s center coordinate and zoom level.
mapView.setCenter(CLLocationCoordinate2D(latitude: 44.370417,
longitude: 7.411713),
zoomLevel: 13, animated: false)
view.addSubview(mapView)
mapView.userTrackingMode = .followWithHeading
// Set the delegate property of our map view to `self` after instantiating it.
mapView.delegate = self
}
#IBaction func didPressButton(sender: UIButton) {
let uno = CustomPointAnnotation(coordinate: CLLocationCoordinate2DMake(44.376362, 7.396907),
title: "**",
subtitle: "**",
controllo: visible)
// Set the custom `image` and `reuseIdentifier` properties, later used in the `mapView:imageForAnnotation:` delegate method.
uno.reuseIdentifier = "montagna"
uno.image = UIImage(named: "montagna")
if uno.controllo == true {
mapView.addAnnotation(uno)
}
else {
//You might want to check if the annotation exist in the map first.
mapView.removeAnnotation(uno)
}
}