Xcode我无法在另一个视图控制器中执行ViewController的功能

Question

有人可以帮我从另一个VC中执行功能吗？一旦按下第二个VC中的按钮，就需要执行第一个VC中的功能。我正在尝试使用“ viewcontroller（）。function（）”函数，但是它不能正常工作，打印和基本的东西都可以工作，但是当涉及到诸如绘制方向之类的东西时，它就不能工作。

绘制方向的功能是：

func directionToPin() {
    //
    //        print("sbfdskbd")
    //        print("drawedDriection\(self.drawedDriection)")
    //        print("didSelectAnnotation\(self.didSelectAnnotation)")

            guard let currentPlacemark = currentPlacemark else {
                print("Error, the current Placemark is: \(self.currentPlacemark)")
                return
            }

            print("dgvwedsvhjgdfskfbdvfjbvhdfbjvjvbvjdkbhcbvnsd")

            let directionRequest = MKDirections.Request()
            let destinationPlacemark = MKPlacemark(placemark: currentPlacemark)

            directionRequest.source = MKMapItem.forCurrentLocation()
            directionRequest.destination = MKMapItem(placemark: destinationPlacemark)
            directionRequest.transportType = .walking

            //calculate route
            let directions = MKDirections(request: directionRequest)
            directions.calculate{ (directionsResponse, error) in
                guard let directionsResponse = directionsResponse else{
                    if let error = error {
                        print("error getting directions: \(error.localizedDescription)")
                    }
                    return
                }

                let route = directionsResponse.routes[0]
                //self.mapView.removeOverlays(self.mapView.overlays)


                if self.drawedDriection == false{
                    self.drawedDriection = true
                    if self.didSelectAnnotation == true {
                        self.mapView.addOverlay(route.polyline, level: .aboveRoads)
                        self.navigationBarController.directionButtonOutlet.setImage(UIImage(named: "navigationBarDirectionButtonRed")?.withRenderingMode(.alwaysOriginal), for: .normal)
                                //directionButtonColor = "red"
                                //self.delegateChangeColors?.changeDirectionButtonColor()
                        let routeRect = route.polyline.boundingMapRect
                        self.mapView.setRegion(MKCoordinateRegion(routeRect), animated: true)
                    }
                } else {
                    self.drawedDriection = false
                    self.mapView.removeOverlays(self.mapView.overlays)
                    if self.didSelectAnnotation == true {
                        self.navigationBarController.directionButtonOutlet.setImage(UIImage(named: "navigationBarDirectionButtonBlue")?.withRenderingMode(.alwaysOriginal), for: .normal)
                                //directionButtonColor = "blue"
                                //self.delegateChangeColors?.changeDirectionButtonColor()
                    } else {
                        self.navigationBarController.directionButtonOutlet.setImage(UIImage(named: "navigationBarDirectionButtonGray")?.withRenderingMode(.alwaysOriginal), for: .normal)
                                //directionButtonColor = "gray"
                                //self.delegateChangeColors?.changeDirectionButtonColor()
                    }
                }
            }
        }

按下按钮后，我将在第二个VC中调用该函数：

    @IBAction func directionButton(_ sender: Any) {
        MapViewController().directionToPin()
    } 

[运行应用程序并按按钮时，currentPlacemark为零，如果我通过第一个VC（内部具有directionToPin函数的VC）中的按钮运行相同的功能，则>]

如果需要，这是我的仓库：https://github.com/octavi42/xCodeMapsApp

谢谢！

有人可以帮我从另一个VC中执行功能吗？一旦按下第二个VC中的按钮，就需要执行第一个VC中的功能。我正在尝试使用“ viewcontroller（）。function（...

Answer 1

我认为您需要使用协议和代表