I have an extremely simple set up in which a MapKit resides within another view. I want the map to be able to be expanded into a fullScreenCover. The map properly shows up in ProfilePageView on initial load, and properly shows up in the fullScreenCover when expanded. However, when the fullScreenCover is exited the map is effectively totally gone (see image below). Clicking on the rectangle again properly sends it back to the fullScreenCover where it is displaying correctly.

I can force it to rerender by using a UUID key, but this seems like a hack and I don’t understand why it is necessary.

import Foundation
import SwiftUI
import UIKit
import MapKit

struct ProfilePageView: View {

    @State private var isMapExpanded: Bool = false

    @State private var mapView: MKMapView
    @State private var mapViewKey: UUID = UUID()

    init(countryNames: [String]) {

        // Initialize MKMapView with configuration
        let initialMapView = MKMapView()
        let initialLocation = CLLocationCoordinate2D(latitude: 33.9391, longitude: 67.7100)
        let regionRadius: CLLocationDistance = 6000000
        let coordinateRegion = MKCoordinateRegion(center: initialLocation, latitudinalMeters: regionRadius, longitudinalMeters: regionRadius)
        initialMapView.setRegion(coordinateRegion, animated: true)
        _mapView = State(initialValue: initialMapView)
        print("MKMapView initialized in init")
    }

    var body: some View {
        ScrollView {
                Divider()

                Button(action: {
                    isMapExpanded = true
                }) {
                    ZStack {
                        MapUserView(isMapLoading: .constant(false), mapView: mapView)
                            .id(mapViewKey)  // Use the key to force recreation
                            .frame(height: 425)
                            .cornerRadius(10)
                            .overlay(
                                RoundedRectangle(cornerRadius: 10)
                                    .stroke(Color.blue, lineWidth: 4)
                            )
                            .allowsHitTesting(false)

                        Rectangle()//
                            .foregroundColor(.clear)
                            .frame(height: 425)
                            .contentShape(Rectangle())
                    }
                }
                .buttonStyle(PlainButtonStyle())
                .fullScreenCover(isPresented: $isMapExpanded, onDismiss: {
                    print("FullScreenCover dismissed")
                    mapViewKey = UUID()  // *If this is commented it we get the above described image*
                }) {
                    MapUserFullScreenView(isPresented: $isMapExpanded, mapView: mapView)
                }

            Text("Here we are")

                
            }

        }
    }




struct MapUserFullScreenView: View {
    @Binding var isPresented: Bool
    var mapView: MKMapView
   

    var body: some View {
        ZStack(alignment: .topLeading) {
            MapUserView(isMapLoading: .constant(false), mapView: mapView)
                .edgesIgnoringSafeArea(.all)
            
            Button(action: {
                isPresented = false
            }) {
                Image(systemName: "xmark.circle.fill")
                    .padding()
                    .font(.largeTitle)
                    .foregroundColor(.white)
            }
            .edgesIgnoringSafeArea(.all)
        }
    }
}

struct ProfilePageView_Previews: PreviewProvider {
    static var previews: some View {
        let randomCountries = ["Brazil", "Colombia"]
      
        
        return ProfilePageView(countryNames: randomCountries)
    }
}

import SwiftUI
import MapKit
struct MapUserView: UIViewRepresentable {
    @Binding var isMapLoading: Bool
    
    var mapView: MKMapView

    func makeUIView(context: Context) -> MKMapView {
        print("UI has been made")
        // Ensure the map view is only configured once
        if mapView.delegate == nil {
            mapView.delegate = context.coordinator

        }
        return mapView
    }

    func updateUIView(_ mapView: MKMapView, context: Context) {
        print("updateUIView called")
        // Ensure the map view is not reset or cleared unintentionally
        if mapView.delegate == nil {
            mapView.delegate = context.coordinator
        }
    }

    func makeCoordinator() -> MapUserCoordinator {
        MapUserCoordinator(self)
    }

    class MapUserCoordinator: NSObject, MKMapViewDelegate {
        var parent: MapUserView
        
        private var cancellables = Set<AnyCancellable>()

        var dimmingView: UIView?

        init(_ parent: MapUserView) {
            self.parent = parent
            
            super.init()
        }

        func mapViewDidFinishLoadingMap(_ mapView: MKMapView) {
            parent.isMapLoading = false
        }
        
    }
}


struct MapUserView_Previews: PreviewProvider {
    static var previews: some View {

        return MapUserView(isMapLoading: .constant(false), mapView: MKMapView())
    }
}

Why is this UUID key necessary? Why isn’t @State properly ensuring the state of the mapview remains shared within the ProfilePageView and that of the value displayed in the fullScreenCover?

Note that I am passing mapView to MapUserView to enable the fullscreencover to display without requiring a full reload of the map information (I have stripped out a lot of the complex methodologies here to focus on the specific problem). Prior to passing this mapView, the button would cause the map to entirely reload before displaying and this would cause significant lag.