I followed along WWDC 2023's Meet MapKit for SwiftUI, but am stumped at how to to use Marker selection for my own data.

Creating a selectedItem: MKMapItem? and assigning that to the map does result in the marker indicating it's selected when tapped. But nothing else happens- my private var selectedPlace computed variable never recomputes. Also if I add a if selectedItem { Text("selected") } block in the body, it never succeeds- always showing that the selectedItem is nil. If I change the type of the selectedItem to a MapFeature, nothing happens when it's tapped.

What do I need to do to get Map to update this variable on selection?

Thanks for any help!

Here's my code:

struct Place: Identifiable {
    let id: String
    let name: String
    let coordinate: CLLocationCoordinate2D
}

struct MapView: View {
    var places: [Place]
    @State private var position: MapCameraPosition = .automatic
    @State private var selectedItem: MKMapItem?

    private var selectedPlace: Place? {
        if let selectedItem {
            return places.first(where: { $0.id.hashValue == selectedItem.hashValue })
        }
        return nil
    }

    var body: some View {
        Map(position: $position, selection: $selectedItem) {
            ForEach(places, id: \.id) { place in
                Marker(
                  place.name,
                  monogram: place.icon,
                  coordinate: place.coordinate
                ).tag(place.id)
            }
        }
        .safeAreaInset(edge: .bottom) {
            if let selectedPlace {
                PlaceInfoView(place: selectedPlace)
                    .frame(height: 128)
                    .clipShape(RoundedRectangle(cornerRadius: 10))
                    .padding([.top, .horizontal])
            }
        }
    }
}

Ooof, finally figured this out. So the selection: since I'm using .tag(\.id), is simply my Place's ID (which is a string. Changing selectedItem: String? fixed it.