您如何让用户在地图上添加图钉并在SwiftUI中获取坐标？

Question

我在以芝加哥为中心的视图中有一张地图。我希望用户能够在地图上放置图钉/注释，然后检索这些坐标。该地图可以很好地加载芝加哥，但我无法使用注释代码。

具体来说，我似乎找不到SwiftUI的答案。只有Swift和Storyboard。我觉得我有99％的代码，但各部分的位置不正确。我提供了错误所在的屏幕截图。感谢您的帮助。

import SwiftUI
import MapKit

struct EntireMapView: UIViewRepresentable {

    func updateUIView(_ mapView: MKMapView, context: Context) {

        mapView.delegate = context.coordinator

        let longPressGesture = UILongPressGestureRecognizer(target: mapView, action: #selector(EntireMapViewCoordinator.addAnnotation(gesture:)))
        mapView.addGestureRecognizer(longPressGesture)

        let span = MKCoordinateSpan(latitudeDelta: 0.3, longitudeDelta: 0.3)

        var chicagoCoordinate = CLLocationCoordinate2D()
        chicagoCoordinate.latitude = 41.878113
        chicagoCoordinate.longitude = -87.629799

        let region = MKCoordinateRegion(center: chicagoCoordinate, span: span)

        mapView.setRegion(region, animated: true)

    }

    func makeUIView(context: Context) -> MKMapView {

        let mapView = MKMapView(frame: .zero)
        mapView.delegate = context.coordinator
        return mapView

    }

    func makeCoordinator() -> EntireMapViewCoordinator {
        return EntireMapViewCoordinator(self)
    }

    class EntireMapViewCoordinator: NSObject, MKMapViewDelegate {

        var entireMapViewController: EntireMapView

        init(_ control: EntireMapView) {
          self.entireMapViewController = control
        }

        func mapView(_ mapView: MKMapView, viewFor annotation: MKAnnotation) -> MKAnnotationView? {
            return (annotation as? MKAnnotationView)!
        }

        @objc func addAnnotation(gesture: UILongPressGestureRecognizer) {

            if gesture.state == .ended {

                let point = gesture.location(in: self.mapView) **<--- ERROR HERE**
                let coordinate = mapView.convert(point, toCoordinateFrom: mapView)

                var annotation = MKPointAnnotation()
                annotation.coordinate = coordinate

                self.mapView.addAnnotation(annotation) **<--- ERROR HERE**
            }
        }
    }
}

struct EntireMapView_Previews: PreviewProvider {
    static var previews: some View {
        EntireMapView()
    }
}

Here's a screen shot of the errors

Answer 1

我将从updateUIView中删除mapView.delegate = context.coordinator开始。在makeUIView中（您已经在做）应该只做一次。