Question

我有一个使用MKMapView的MapView，还有一个HomeView，其中显示了MapView和ResultsCarouselView（现在为方便起见，将其替换为Circle）。

如果我有一个可观察对象来管理此HomeView的状态，是否可以从协调器使用它？例如，我从协调器中的HomeState调用的任何内容都不会更新HomeView：

MapCoordinator

final class MapCoordinator: NSObject, MKMapViewDelegate {
  @ObservedObject var homeState = HomeState()

  // other code, init, etc.

  func mapView(_ mapView: MKMapView, didUpdate userLocation: MKUserLocation) {
    self.homeState.setUserLocated(true)
  }
}

HomeState：

class HomeState: NSObject, ObservableObject {
  @Published var userLocated = false

  func setUserLocated(_ value: Bool) {
    self.userLocated = value // debugger comes here, but is this another instance or something?
  }
}

HomeView：

struct HomeView: View {
  @ObservedObject var homeState = HomeState()
  
  var body: some View {
    ZStack(alignment: .bottom) {
      MapView()

      if (homeState.userLocated) {
         Circle()   // this doesn't show up
      }
    }
  }
}

Answer 1

struct MapView: UIViewRepresentable {
@ObservedObject var homeState = HomeState()

func makeUIView(context: Context) -> MKMapView {
    let mapView = MKMapView()
    mapView.delegate = context.coordinator
    return mapView
}

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

}

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

class Coordinator: NSObject, MKMapViewDelegate {
    var parent: MapView

    init(_ parent: MapView) {
        self.parent = parent
    }

    func mapView(_ mapView: MKMapView, didUpdate userLocation: MKUserLocation) {
        self.parent.homeState.setUserLocated(true)
    }
}
}

您可以使用parent中的Coordinator变量来修改任何@State或@ObservableObject，例如您的HomeState @ObservedObject

我可以在协调器内部使用ObservedObject吗？

1 个答案: