MapKit：两个注释之间未显示路线

Question

我试图显示两个注释之间的路线。

注释和区域工作正常，但路线不会显示，我不知道为什么 看起来路线根本没有被渲染。 我确定该路线存在，因为我尝试打印它并且它位于directionResponse.routes 有什么建议吗？

我正在使用 SwiftUI

然后这包含在父视图中。

import SwiftUI
import MapKit
import FirebaseFirestore

struct MapView: UIViewRepresentable {
    var packageLocation: GeoPoint
    var destination: GeoPoint
    var driverLocation = CLLocationCoordinate2D()

    func makeUIView(context: UIViewRepresentableContext<MapView>) -> MKMapView {
        MKMapView()
    }

    func mapView(_ mapView: MKMapView, rendererFor overlay: MKOverlay) -> MKOverlayRenderer {
        let renderer = MKPolygonRenderer(overlay: overlay)
        renderer.strokeColor = .blue
        renderer.lineWidth = 2.0
        return renderer
    }


    func updateUIView(_ uiView: MKMapView, context: UIViewRepresentableContext<MapView>) {
        let requestLocation: CLLocationCoordinate2D = CLLocationCoordinate2D(latitude: packageLocation.latitude, longitude: packageLocation.longitude)
        let destinationLocation: CLLocationCoordinate2D = CLLocationCoordinate2D(latitude: destination.latitude, longitude: destination.longitude)

        //let span = MKCoordinateSpan(latitudeDelta: 1, longitudeDelta: 1)
        //let region = MKCoordinateRegion(center: requestLocation, span: span)
        //uiView.setRegion(region, animated: true)

        let annotation = MKPointAnnotation()
        annotation.coordinate = requestLocation
        annotation.title = "Package Title"
        uiView.addAnnotation(annotation)

        let annotation2 = MKPointAnnotation()
        annotation2.coordinate = destinationLocation
        annotation2.title = "Destiantion"
        uiView.addAnnotation(annotation2)

        let sourcePlacemark = MKPlacemark(coordinate: requestLocation)
        let destinationPlacemark = MKPlacemark(coordinate: destinationLocation)


        let directionRequest = MKDirections.Request()
        directionRequest.source = MKMapItem(placemark: sourcePlacemark)
        directionRequest.destination = MKMapItem(placemark: destinationPlacemark)
        directionRequest.transportType = .automobile

        let directions = MKDirections(request: directionRequest)

        directions.calculate { (response, error) in
            guard let directionResponse = response else {
                if let error = error {
                    print(error.localizedDescription)
                }
                return
            }
            print(directionResponse)

            let route = directionResponse.routes[0]
            uiView.addOverlay(route.polyline, level: .aboveRoads)

            let rect = route.polyline.boundingMapRect
            uiView.setRegion(MKCoordinateRegion(rect), animated: true)
        }

    }
}

Answer 1

你几乎得到它。

您需要解决的一个问题是使用MKMapView 委托函数。

最简单的方法是继承MKMapView 并制作符合MKMapViewDelegate 的地图视图。

首先，创建自己的地图视图，继承MKMapView 并符合MKMapViewDelegate。目前您只真正使用了rendererFor overlay 委托方法，所以我将实现它，但您可以根据需要添加其他方法。

class WrappableMapView: MKMapView, MKMapViewDelegate {

    func mapView(_ mapView: MKMapView, rendererFor overlay: MKOverlay) -> MKOverlayRenderer {
        let renderer = MKPolylineRenderer(overlay: overlay)
        renderer.strokeColor = .red
        renderer.lineWidth = 4.0
        return renderer
    }
}

然后您需要更新您的UIViewRepresentable 以使用您刚刚创建的新WrappableMapView。我已经制作了一个功能示例，所以在这里我传递了请求和目标位置。你可以随心所欲地处理它，但至少这会给你一些有用的东西。

struct MyMapView: UIViewRepresentable {

    @Binding var requestLocation: CLLocationCoordinate2D
    @Binding var destinationLocation: CLLocationCoordinate2D

    private let mapView = WrappableMapView()

    func makeUIView(context: UIViewRepresentableContext<MyMapView>) -> WrappableMapView {
        mapView.delegate = mapView // make sure we set our delegate to be the mapView we just created
        return mapView
    }

    func updateUIView(_ uiView: WrappableMapView, context: UIViewRepresentableContext<MyMapView>) {

        let requestAnnotation = MKPointAnnotation()
        requestAnnotation.coordinate = requestLocation
        requestAnnotation.title = "Package Title"
        uiView.addAnnotation(requestAnnotation)

        let destinationAnnotation = MKPointAnnotation()
        destinationAnnotation.coordinate = destinationLocation
        destinationAnnotation.title = "Destination"
        uiView.addAnnotation(destinationAnnotation)

        let requestPlacemark = MKPlacemark(coordinate: requestLocation)
        let destinationPlacemark = MKPlacemark(coordinate: destinationLocation)

        let directionRequest = MKDirections.Request()
        directionRequest.source = MKMapItem(placemark: requestPlacemark)
        directionRequest.destination = MKMapItem(placemark: destinationPlacemark)
        directionRequest.transportType = .automobile

        let directions = MKDirections(request: directionRequest)
        directions.calculate { response, error in
            guard let response = response else { return }

            let route = response.routes[0]
            uiView.addOverlay(route.polyline, level: .aboveRoads)

            let rect = route.polyline.boundingMapRect
            uiView.setRegion(MKCoordinateRegion(rect), animated: true)

            // if you want insets use this instead of setRegion
            //  uiView.setVisibleMapRect(rect, edgePadding: .init(top: 50.0, left: 50.0, bottom: 50.0, right: 50.0), animated: true)
        }

    }
}

最后，我们可以将它们与表明它有效的 ContentView 放在一起：

struct ContentView: View {

    @State var requestLocation = CLLocationCoordinate2D(latitude: 51.509865, longitude:  -0.118092)
    @State var destinationLocation = CLLocationCoordinate2D(latitude: 51.501266, longitude: -0.093210)

    var body: some View {
        MyMapView(requestLocation: $requestLocation, destinationLocation: $destinationLocation)
    }
}

它应该是这样的：

---

有一点需要注意，在模拟器中使用rendererFor overlay 委托函数会导致error。这只发生在模拟器中而不是设备上，所以如果您在控制台中看到这样的错误消息，请不要感到惊讶。

2019-11-08 18:50:30.034066+0000 StackOverflow[80354:9526181] Compiler error: Invalid library file