Swiftui-mapkit-multipolyline.swift

struct ContentView: View {

    var body: some View {
        PolylineMapView()
    }
}

struct PolylineMapView: UIViewRepresentable {
    func makeCoordinator() -> MapViewCoordinator{
         return MapViewCoordinator(self)
    }
    
    func updateUIView(_ view: MKMapView, context: Context){

        view.delegate = context.coordinator
        let b2MLocation = [CLLocationCoordinate2D(
        latitude: 12.9352, longitude: 77.6244), CLLocationCoordinate2D(
        latitude: 19.0760, longitude: 72.8777)]
        let m2DLocation = [CLLocationCoordinate2D(
        latitude: 19.0760, longitude: 72.8777),
                           CLLocationCoordinate2D(latitude: 28.7041, longitude: 77.1025)]
        let d2BLocation = [CLLocationCoordinate2D(latitude: 28.7041, longitude: 77.1025),
                           CLLocationCoordinate2D(
                           latitude: 12.9352, longitude: 77.6244)]
        
        let polyline1 = MKPolyline(coordinates: b2MLocation, count: b2MLocation.count)
        let polyline2 = MKPolyline(coordinates: m2DLocation, count: m2DLocation.count)
        let polyline3 = MKPolyline(coordinates: d2BLocation, count: d2BLocation.count)
        view.addOverlays([polyline1, polyline2, polyline3])
    }
    
    func makeUIView(context: Context) -> MKMapView{
         MKMapView(frame: .zero)
    }
}

class MapViewCoordinator: NSObject, MKMapViewDelegate {
        var mapViewController: PolylineMapView
        
        init(_ control: PolylineMapView) {
          self.mapViewController = control
        }
    
        func mapView(_ mapView: MKMapView, rendererFor overlay: MKOverlay) -> MKOverlayRenderer {

        if let multiPolyline = overlay as? MKMultiPolyline{
            let polylineRenderer = MKMultiPolylineRenderer(multiPolyline: multiPolyline)
            polylineRenderer.strokeColor = UIColor.blue.withAlphaComponent(0.5)
            polylineRenderer.lineWidth = 5
        }
        return MKOverlayRenderer(overlay: overlay)
    }
}