实际上，源变量和目标变量都为nil。因此，我从server。如果收到错误响应，请尝试以下代码
func addRoutesOverLayForMapView(){ var source:MKMapItem? var destination:MKMapItem? var sourcePlacemark = MKPlacemark(coordinate: pickUpDistanceLocation!.coordinate, addressDictionary: nil) source = MKMapItem(placemark: sourcePlacemark) var desitnationPlacemark = MKPlacemark(coordinate: dropOffDistanceLocation!.coordinate, addressDictionary: nil) destination = MKMapItem(placemark: desitnationPlacemark) let request:MKDirectionsRequest = MKDirectionsRequest() request.setSource(source) request.setDestination(destination) request.transportType = MKDirectionsTransportType.Walking let directions = MKDirections(request: request) directions.calculateDirectionsWithCompletionHandler ({ (response: MKDirectionsResponse?, error: NSError?) in if error == nil { self.showRoute(response!) } else{ println("trace the error (error?.localizedDescription)") } }) }func showRoute(response:MKDirectionsResponse){ for route in response.routes as! [MKRoute]{ mapView.addOverlay(route.polyline, level: MKOverlayLevel.AboveRoads) var routeSeconds = route.expectedTravelTime let routeDistance = route.distance println("distance between two points is (routeSeconds) and (routeDistance)") }}而且您应该实现此委托方法，不要忘记设置mapview委托
func mapView(mapView: MKMapView!, rendererForOverlay overlay: MKOverlay!) -> MKOverlayRenderer! { if overlay is MKPolyline { var polylineRenderer = MKPolylineRenderer(overlay: overlay) polylineRenderer.lineDashPattern = [14,10,6,10,4,10] polylineRenderer.strokeColor = UIColor(red: 0.012, green: 0.012, blue: 0.012, alpha: 1.00) polylineRenderer.lineWidth = 2.5 return polylineRenderer } return nil }
