绘制折线以获取更新的坐标

Question

计划是为驾驶员绘制折线。驱动程序的坐标来自API并保存在Place中。每1分钟在数据库中更新驱动程序的坐标。

我有一个代码，我尝试过工作，但它没有在地图上显示任何内容。

 var places = [Place]()

let locationManager = CLLocationManager()



override func viewDidLoad() {
    super.viewDidLoad()
    requestLocationAccess()
    addAnnotations()
    addPolyline()
    addPolygon()

}

override func viewWillAppear(_ animated: Bool) {
    super.viewWillAppear(true)
    getOrderData ()

}


func addAnnotations() {
    mapView?.delegate = self
    mapView?.addAnnotations(places)

    let overlays = places.map { MKCircle(center: $0.coordinate, radius: 20) }
    mapView?.addOverlays(overlays)

    // Add polylines

            var locations = places.map { $0.coordinate }
            print("Number of locations: \(locations.count)")
            let polyline = MKPolyline(coordinates: &locations, count: locations.count)
            mapView?.add(polyline)

}




func addPolyline() {
    var locations = places.map { $0.coordinate }
    let polyline = MKPolyline(coordinates: &locations, count: locations.count)

    mapView?.add(polyline)
}

func addPolygon() {
    var locations = places.map { $0.coordinate }
    let polygon = MKPolygon(coordinates: &locations, count: locations.count)
    mapView?.add(polygon)
}

func mapView(_ mapView: MKMapView, rendererFor overlay: MKOverlay) -> MKOverlayRenderer {
    if overlay is MKCircle {
        let renderer = MKCircleRenderer(overlay: overlay)
        renderer.fillColor = UIColor.black.withAlphaComponent(0.5)
        renderer.strokeColor = UIColor.blue
        renderer.lineWidth = 2
        return renderer

    } else if overlay is MKPolyline {
        let renderer = MKPolylineRenderer(overlay: overlay)
        renderer.strokeColor = UIColor.orange
        renderer.lineWidth = 3
        return renderer

    } else if overlay is MKPolygon {
        let renderer = MKPolygonRenderer(polygon: overlay as! MKPolygon)
        renderer.fillColor = UIColor.black.withAlphaComponent(0.5)
        renderer.strokeColor = UIColor.orange
        renderer.lineWidth = 2
        return renderer
    }

    return MKOverlayRenderer()
}

func getOrderData () {
    let param = ["user_id":"12299"]
    let urlStr = "/client/current_order"
    let url = URL(string: urlStr)




    Alamofire.request(url!, method: .post, parameters: param,encoding: URLEncoding.default, headers: headers).responseJSON { response in


            // get data

             let driver = data["orders"][0]["driver"]

            let lat = driver["lat"].stringValue
            let lng = driver["lng"].stringValue

            let position = Place(coordinate: CLLocationCoordinate2DMake(Double(lat)!, Double(lng)!))


            self.places.append(position)

            print(self.places)
        }

结果是一张空地图。