Customize Mapbox style with layers in SwiftUI - swiftui

Question

I have an issue to customize a Mapbox view's style, like for instance adding some information on the map if a switch is switched on. Not sure if it's important, but the layers I need to add are MGLSymbolStyleLayer and MGLLineStyleLayer.
Let's start with code for the main view containing a switch representing a state used to customize the map's style, and an UIViewRepresentable for the Mapbox view.
struct Test_MapBox: View {
#State private var styleURL: URL = MGLStyle.outdoorsStyleURL
#State private var switchButton: Bool = false
var body: some View {
ZStack(alignment: .bottom) {
MapView(switchButton: switchButton)
.styleURL(styleURL)
.edgesIgnoringSafeArea(.all)
Toggle(isOn: $switchButton, label: {
Text("Switch")
})
}
}
}
struct MapView: UIViewRepresentable {
var switchButton: Bool
var mapView = MGLMapView(frame: .zero)
func makeUIView(context: UIViewRepresentableContext<MapView>) -> MGLMapView {
mapView.delegate = context.coordinator
return mapView
}
func updateUIView(_ uiView: MGLMapView, context: UIViewRepresentableContext<MapView>) {
print("Style: \(uiView.style)")
print("Update view, switch: \(switchButton)")
}
func makeCoordinator() -> MapView.Coordinator {
Coordinator(self)
}
func styleURL(_ styleURL: URL) -> MapView {
mapView.styleURL = styleURL
return self
}
final class Coordinator: NSObject, MGLMapViewDelegate {
var parent: MapView
init(_ control: MapView) {
self.parent = control
}
func mapViewDidFinishLoadingMap(_ mapView: MGLMapView) {
print("Map loaded, switch: \(parent.switchButton)")
}
func mapView(_ mapView: MGLMapView, didFinishLoading style: MGLStyle) {
print("Style loaded, switch: \(parent.switchButton)")
}
}
}
The issue is the following: inside the delegate functions, switchButton is never up to date, always false (and I don't understand why)... And in updateUIView(), switchButton is OK, but the style is not yet loaded, so usually you get a nil when accessing it ...
Have you got a solution ?