// ios 14 only
struct NewMapView: View {

    @Binding var lat : Double
    @Binding var lon : Double

    @State var region = MKCoordinateRegion(center: CLLocationCoordinate2D(
    //latitude: lat, longitude: lon),
    latitude: 53.8862, longitude: 8.6706),
    latitudinalMeters: 250, longitudinalMeters: 250 )

    private func setRegio(){
        region = MKCoordinateRegion(center: CLLocationCoordinate2D(
                latitude: lat, longitude: lon),
                latitudinalMeters: 250, longitudinalMeters: 250)
    }

    var body: some View {
        if #available(iOS 14.0, *) {
           Map(coordinateRegion: $region)
                .onAppear {self.setRegio()}
        } else {
            EntireMapView(lat: $lat, lon: $lon) // Fallback on earlier versions
        }
    }
}

Hi,

I hope someone can help me. How can I bind my two variables lat and lon to @State var region? .onAppear is the first approach, but indeed too late. Thanks a lot for your support. With regards Peter from Germany

Hey Peter,

Here's a solution that will work in SwiftUI 2.0. It's slightly verbose, but it works reliably and well:

struct MapView: View {
    @Binding private var lat: Double
    @Binding private var lon: Double

    private let initialLatitudinalMetres: Double = 250
    private let initialLongitudinalMetres: Double = 250

    @State private var span: MKCoordinateSpan?

    init(lat: Binding<Double>, lon: Binding<Double>) {
        _lat = lat
        _lon = lon
    }

    private var region: Binding<MKCoordinateRegion> {
        Binding {
            let centre = CLLocationCoordinate2D(latitude: lat, longitude: lon)

            if let span = span {
                return MKCoordinateRegion(center: centre, span: span)
            } else {
                return MKCoordinateRegion(center: centre, latitudinalMeters: initialLatitudinalMetres, longitudinalMeters: initialLongitudinalMetres)
            }
        } set: { region in
            lat = region.center.latitude
            lon = region.center.longitude
            span = region.span
        }
    }

    var body: some View {
        Map(coordinateRegion: region)
    }
}

Then to use it:

struct ContentView: View {
    @State private var lat = 50.1018
    @State private var lon = 14.2632

    var body: some View {
        MapView(lat: $lat, lon: $lon)
    }
}