MapKit：兩個注釋之間未顯示路線

Question

我試圖顯示兩個注釋之間的路線。

注釋和區域工作正常，但路線不會顯示，我不知道為什么看起來路線根本沒有被渲染。 我確定該路線存在，因為我試圖打印它並且它在directionResponse.routes有什么建議嗎？

我正在使用 SwiftUI

然后將其包含在父視圖中。

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

你幾乎明白了。

您需要解決的一個問題是使用MKMapView委托函數。

最簡單的方法是繼承MKMapView並制作您自己的符合MKMapViewDelegate的 map 視圖。

首先，創建自己的 map 視圖，繼承MKMapView並符合MKMapViewDelegate 。 目前您只是真正使用rendererFor overlay委托方法，所以我將實現它，但如果您需要，您可以添加其他方法。

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以使用您剛剛創建的新WrappableMapView 。 我已經制作了一個功能示例，所以在這里我傳遞了請求和目標位置。 你可以隨心所欲地處理它，但至少這會給你一些有用的東西。

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，我們可以將它們與一個顯示它有效的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)
    }
}

這應該是這樣的：

---

需要注意的一點是，在模擬器中使用rendererFor overlay委托 function 會導致錯誤。 這只會發生在模擬器中而不是設備上，因此如果您在控制台中看到這樣的錯誤消息，請不要感到驚訝。

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