折线叠加未显示在 MapView 上

编程问答 2022-05-28

问题描述

我目前正在使用 Swift 和 Firebase 构建 Uber 克隆，跟随 Stephan Dowless 的 course on Udemy 以了解有关 MapKit 的更多信息，到目前为止进展顺利，但我正在努力向地图，显示从用户当前位置到注释的路线（通过点击 tableView 中显示的搜索结果之一添加到 mapView）。

我在 SO 上寻找了其他类似的问题，但没有找到任何可以回答我的问题的问题。我还尝试克隆其他使用此功能的项目（the completed Uber clone from the Udemy course、this Ray Wenderlich tutorial 和 this article on polylines using SwiftUI）来检查是否是我的代码有问题，但它们都存在相同的问题，即注释出现在屏幕上，但根本不出现叠加层。

在我的应用中，点击 this screen 中 tableView 上的“Starbucks”会产生 this screen（显示星巴克和用户当前位置的注释，但没有叠加）。

同样，运行前面提到的 SwiftUI MapKit tutorial app from Medium 会显示 this（两个注释但没有叠加）。

这让我相信这是我这边出了问题。我也试过在我的手机 (iPhone 7) 上运行这些应用，但遇到了同样的问题。

以下是相关的代码行：

属性声明，包括 route 和 mapView

quick brown fox

ma​​pView 委托设置为 self（确认用户登录时调用的函数）

// MARK:- Properties
    
    private let mapView = MKMapView()
    private var searchResults = [MKPlacemark]()
    private var route: MKRoute?

MapView 函数

private func configureMapView() {
        view.addSubview(mapView)
        mapView.frame = view.frame
        
        mapView.delegate = self
        
        mapView.showsUserLocation = true
        mapView.userTrackingMode = .follow
    }

TableView didSelectRowAt 方法

// MARK:- MapView Functions

extension HomeViewController: MKMapViewDelegate {
    
    private func generatePolyline(toDestination destination: MKMapItem) {
        let request = MKDirections.Request()
        request.source = MKMapItem.forCurrentLocation()
        request.destination = destination
        request.transportType = .automobile
        
        let directionRequest = MKDirections(request: request)
        directionRequest.calculate { (response,error) in
            guard let response = response else { return }
            self.route = response.routes[0]
            guard let polyline = self.route?.polyline else { return }
            self.mapView.addOverlay(polyline)
            
        }
    }
    
    private func searchBy(naturalLanguageQuery: String,completion: @escaping([MKPlacemark]) -> Void) {
        var results = [MKPlacemark]()
        
        let request = MKLocalSearch.Request()
        request.region = mapView.region
        request.naturalLanguageQuery = naturalLanguageQuery
        
        let search = MKLocalSearch(request: request)
        search.start { (response,error) in
            guard let response = response else { return }
            
            response.mapItems.forEach { (item) in
                results.append(item.placemark)
            }
            completion(results)
        }
        
    }
    
    // Change driver annotation appearance to Uber arrow
    public func mapView(_ mapView: MKMapView,viewFor annotation: MKAnnotation) -> MKAnnotationView? {
        if let annotation = annotation as? DriverAnnotation {
            let view = MKAnnotationView(annotation: annotation,reuseIdentifier: DriverAnnotation.identifier)
            view.image = #imageLiteral(resourceName: "chevron-sign-to-right")
            return view
        }
        return nil
    }
    
    func mapView(_ mapView: MKMapView,rendererFor overlay: MKOverlay) -> MKOverlayRenderer {
        if let route = self.route {
            let polyline = route.polyline
            let lineRenderer = MKPolylineRenderer(overlay: polyline)
            lineRenderer.strokeColor = .mainBlueTint
            lineRenderer.lineWidth = 4
            return lineRenderer
        }
        return MKOverlayRenderer()
    }
}

最后，这是整个视图控制器，以防万一我错过了上面的任何内容。如果回答问题需要更多信息，请告诉我，我会提供。

整个视图控制器

func tableView(_ tableView: UITableView,didSelectRowAt indexPath: IndexPath) {
        let placemark = self.searchResults[indexPath.row]
        
        configureActionButtonState(config: .dismissActionView)
        
        let destination = MKMapItem(placemark: placemark)
        self.generatePolyline(toDestination: destination)
        
        self.dismissInputView { _ in
            let annotation = MKPointAnnotation()
            annotation.coordinate = placemark.coordinate
            self.mapView.addAnnotation(annotation)
            self.mapView.selectAnnotation(annotation,animated: true)
            
        }
    }

这也是调试窗口中的输出，不确定它是否相关：

import UIKit
import Firebase
import MapKit

private enum ActionButtonConfiguration {
    case showMenu
    case dismissActionView
    
    init() {
        self = .showMenu
    }
}

class HomeViewController: UIViewController {
    
    // MARK:- Properties
    
    private let mapView = MKMapView()
    private let locationManager = LocationHandler.shared.locationManager
    private let inputActivationView = LocationInputActivationView()
    private let locationInputView = LocationInputView()
    private var searchResults = [MKPlacemark]()
    private var actionButtonConfig = ActionButtonConfiguration()
    private var route: MKRoute?
    
    private let tableView = UITableView()
    
    private var user: User? {
        didSet {
            locationInputView.user = user
        }
    }
    
    private let actionButton: UIButton = {
       let button = UIButton()
        button.setImage(#imageLiteral(resourceName: "baseline_menu_black_36dp").withRenderingMode(.alwaysOriginal),for: .normal)
        button.addTarget(self,action: #selector(didTapActionButton),for: .touchUpInside)
        return button
    }()
    
    
    // MARK:- Lifecycle
    
    override func viewDidLoad() {
        super.viewDidLoad()
        checkIfUserLoggedIn()
        locationManagerDidChangeAuthorization(locationManager!)
        
    }
    
    // MARK:- Selectors
    
    @objc private func didTapActionButton() {
        switch actionButtonConfig {
        case .showMenu:
            print("Show menu")
        case .dismissActionView:
            removeAnnotationsAndOverlays()
            
            UIView.animate(withDuration: 0.3) {
                self.configureActionButtonState(config: .showMenu)
                self.inputActivationView.alpha = 1
            }
        }
    }
    
    // MARK:- API
    
    private func fetchUserData() {
        guard let currentUserId = Auth.auth().currentUser?.uid else { return }
        Service.shared.fetchUserData(uid: currentUserId) { user in
            self.user = user
        }
        
    }
    
    // N.B. Service.shared.fetchDrivers automatically gets called every time the location of the driver changes since it is observing the database via geofire (see definition of this within Service.swift)
    private func fetchDrivers() {
        guard let location = locationManager?.location else { return }
        Service.shared.fetchDrivers(location: location) { (driver) in
            guard let coordinate = driver.location?.coordinate else { return }
            let annotation = DriverAnnotation(uid: driver.uid,coordinate: coordinate)
            
            var driverIsVisible: Bool {
                return self.mapView.annotations.contains { annotation -> Bool in
                    guard let driverAnnotation = annotation as? DriverAnnotation else { return false }
                    if driverAnnotation.uid == driver.uid {
                        // Driver is already visible - update driver location whenever this function is called
                        driverAnnotation.updateAnnotationPosition(withCoordinate: coordinate)
                        return true
                    }
                    
                    // Driver is not visible
                    return false
                }
                
            }
            
            // If driver is not visible then add to map
            if !driverIsVisible {
                self.mapView.addAnnotation(annotation)
            }
            
            
        }
    }
    
    private func checkIfUserLoggedIn() {
        if Auth.auth().currentUser == nil {
            // User is not logged in
            print("DEBUG: User is not logged in")
            DispatchQueue.main.async {
                let nav = UINavigationController(rootViewController: LoginViewController())
                nav.isModalInPresentation = true
                nav.modalPresentationStyle = .fullScreen
                self.present(nav,animated: true,completion: nil)
            }
        } else {
            // User is logged in
            configure()
        }
        
    }
    
    private func logOut() {
        do {
            try Auth.auth().signOut()
            DispatchQueue.main.async {
                let nav = UINavigationController(rootViewController: LoginViewController())
                nav.isModalInPresentation = true
                nav.modalPresentationStyle = .fullScreen
                self.present(nav,completion: nil)
            }
        } catch {
            print("DEBUG: Error signing user out: \(error)")
        }
    }
    
    // MARK:- Public Helper Functions
    
    public func configure() {
        configureUI()
        fetchUserData()
        fetchDrivers()
    }
    
    public func configureUI() {
        configureMapView()
        configureActionButton()
        configureInputActivationView()
        configureTableView()
    }
    
    // MARK:- Private Helper Functions
    
    private func configureActionButton() {
        view.addSubview(actionButton)
        actionButton.anchor(top: view.safeAreaLayoutGuide.topAnchor,left: view.safeAreaLayoutGuide.leftAnchor,paddingTop: 16,paddingLeft: 16,width: 30,height: 30)
    }
    
    private func configureActionButtonState(config: ActionButtonConfiguration) {
        switch config {
        case .showMenu:
            self.actionButton.setImage(#imageLiteral(resourceName: "baseline_menu_black_36dp").withRenderingMode(.alwaysOriginal),for: .normal)
            self.actionButtonConfig = .showMenu
        case .dismissActionView:
            self.actionButton.setImage(#imageLiteral(resourceName: "baseline_arrow_back_black_36dp-1").withRenderingMode(.alwaysOriginal),for: .normal)
            self.actionButtonConfig = .dismissActionView
        }
    }
    
    private func configureMapView() {
        view.addSubview(mapView)
        mapView.frame = view.frame
        
        mapView.delegate = self
        
        mapView.showsUserLocation = true
        mapView.userTrackingMode = .follow
    }
    
    private func configureInputActivationView() {
        inputActivationView.delegate = self
        
        view.addSubview(inputActivationView)
        inputActivationView.centerX(inView: view)
        inputActivationView.anchor(top: actionButton.bottomAnchor,right: view.safeAreaLayoutGuide.rightAnchor,paddingTop: 18,paddingLeft: 20,paddingRight: 20,height: 40)
        
        // Animate inputActivationView (fade in)
        inputActivationView.alpha = 0
        UIView.animate(withDuration: 2) {
            self.inputActivationView.alpha = 1
        }
    }
    
    private func configureLocationInputView() {
        locationInputView.delegate = self
        
        view.addSubview(locationInputView)
        locationInputView.anchor(top: view.topAnchor,left: view.leftAnchor,right: view.rightAnchor,height: 200)
        locationInputView.alpha = 0
        
        UIView.animate(withDuration: 0.5) {
            self.locationInputView.alpha = 1
        } completion: { _ in
            print("DEBUG: Present table view")
            UIView.animate(withDuration: 0.3) {
                self.tableView.frame.origin.y = self.locationInputView.frame.height
            }
        }
    }
    
    private func configureTableView() {
        view.addSubview(tableView)
        
        tableView.delegate = self
        tableView.dataSource = self
        
        tableView.register(LocationTableViewCell.self,forCellReuseIdentifier: LocationTableViewCell.identifier)
        
        tableView.rowHeight = 60
        tableView.tableFooterView = UIView()
        
        let height = view.frame.height - locationInputView.frame.height
        tableView.frame = CGRect(x: 0,y: view.frame.height,width: view.frame.width,height: height)
    }
    
    private func dismissInputView(completion: ((Bool) -> Void)? = nil) {
        UIView.animate(withDuration: 0.3,animations: {
            self.locationInputView.alpha = 0
            self.tableView.frame.origin.y = self.view.frame.height
            self.locationInputView.removeFromSuperview()
        },completion: completion)
    }
    
    private func removeAnnotationsAndOverlays() {
        mapView.annotations.forEach { annotation in
            if let anno = annotation as? MKPointAnnotation {
                mapView.removeAnnotation(anno)
            }
        }
        if mapView.overlays.count > 0 {
            mapView.removeOverlay(mapView.overlays[0])
        }
    }
    
}

// MARK:- MapView Functions

extension HomeViewController: MKMapViewDelegate {
    
    private func generatePolyline(toDestination destination: MKMapItem) {
        let request = MKDirections.Request()
        request.source = MKMapItem.forCurrentLocation()
        request.destination = destination
        request.transportType = .automobile
        
        let directionRequest = MKDirections(request: request)
        directionRequest.calculate { (response,rendererFor overlay: MKOverlay) -> MKOverlayRenderer {
        if let route = self.route {
            let polyline = route.polyline
            let lineRenderer = MKPolylineRenderer(overlay: polyline)
            lineRenderer.strokeColor = .mainBlueTint
            lineRenderer.lineWidth = 3
            return lineRenderer
        }
        return MKOverlayRenderer()
    }
}

// MARK:- Location Manager Services

extension HomeViewController {
    
    func locationManagerDidChangeAuthorization(_ manager: CLLocationManager) {
        
        switch manager.authorizationStatus {
        case .notDetermined:
            print("DEBUG: Not determined")
            locationManager?.requestWhenInUseAuthorization()
        case .restricted:
            break
        case .denied:
            break
        case .authorizedAlways:
            print("DEBUG: Auth always")
            locationManager?.startUpdatingLocation()
            locationManager?.desiredAccuracy = kCLLocationAccuracyBest
        case .authorizedWhenInUse:
            print("DEBUG: Auth when in use")
            locationManager?.requestAlwaysAuthorization()
        @unknown default:
            break
        }
    }
}

// MARK:- Input Activation View Delegate Methods

extension HomeViewController: LocationInputActivationViewDelegate {
    func presentLocationInputView() {
        configureLocationInputView()
        self.inputActivationView.alpha = 0
    }
    
}

// MARK:- Input View Delegate Methods

extension HomeViewController: LocationInputViewDelegate {
    func executeSearch(query: String) {
        searchBy(naturalLanguageQuery: query) { (results) in
            print("DEBUG: Placemarks are \(results)")
            self.searchResults = results
            self.tableView.reloadData()
        }
        
    }
    
    func dismissLocationInputView() {
        dismissInputView()
        UIView.animate(withDuration: 0.5) {
            self.inputActivationView.alpha = 1
        }
    }
}

// MARK:- TableView Delegate and Datasource Methods

extension HomeViewController: UITableViewDelegate,UITableViewDataSource {
    func numberOfSections(in tableView: UITableView) -> Int {
        2
    }
    
    func tableView(_ tableView: UITableView,titleForHeaderInSection section: Int) -> String? {
        return "test"
    }
    
    func tableView(_ tableView: UITableView,numberOfRowsInSection section: Int) -> Int {
        return section == 0 ? 2 : searchResults.count
    }
    
    func tableView(_ tableView: UITableView,cellForRowAt indexPath: IndexPath) -> UITableViewCell {
        let cell = tableView.dequeueReusableCell(withIdentifier: LocationTableViewCell.identifier,for: indexPath) as! LocationTableViewCell
        if indexPath.section == 1 {
            cell.placemark = searchResults[indexPath.row]
        }
        return cell
    }
    
    func tableView(_ tableView: UITableView,animated: true)
            
        }
    }
}

提前致谢！

解决方法

我已经创建了一个简化版本 - 使用硬编码的目的地，但按照您的方式创建路线，这非常有效。

private func generatePolyline(toDestination destination: MKMapItem) {
    let request = MKDirections.Request()
    request.source = MKMapItem.forCurrentLocation()
    request.destination = destination
    request.transportType = .automobile
    
    let directionRequest = MKDirections(request: request)
    directionRequest.calculate { (response,error) in
        guard let response = response else { return }
        self.route = response.routes[0]
        guard let polyline = self.route?.polyline else { return }
        self.mapView.addOverlay(polyline)
        print("update map?")
    }
}

我在这里添加的唯一内容是最后的调试打印语句 - 总是很高兴知道某些事情应该发生，但知道它确实发生了总是很高兴！

我从一个简单的测试按钮调用了这个函数

@IBAction func cmdButton(_ sender: Any) {
    // for testing - Edinburgh Castle
    generatePolyline(toDestination: MKMapItem(placemark: MKPlacemark(coordinate: CLLocationCoordinate2D(latitude:  55.9483,longitude: -3.1981),addressDictionary: nil)))
}

渲染器非常简单，包括上面的测试打印

func mapView(_ mapView: MKMapView,rendererFor overlay: MKOverlay) -> MKOverlayRenderer {
        let pr = MKPolylineRenderer(overlay: overlay)
        pr.strokeColor = UIColor.red.withAlphaComponent(0.5)
        pr.lineWidth = 7
        print("rendererFor overlay")
        return pr
}

如果您看到调试打印注释，您应该没问题。让我知道你的进展如何...

,

深入挖掘后，原因是我在柬埔寨金边。 Apple Maps 无法在柬埔寨提供方向。如果我想从一个点到另一个点画一条线，我猜我将不得不求助于谷歌地图。

iosiosmapkitpolylineswiftswiftswift

相关问答

matplotlib报错：AttributeError: module 'backend_interagg' has no attribute 'FigureCanvas'. Did you mean: 'FigureCanvasAgg'?
使用本地python环境可以成功执行 import pandas as pd impor...
gitlab登录失败，报错：This challenge page was accidentally cached by an intermediary and is no longer available.
设置时间 控制面板
后端开发常见错误
错误1：Request method ‘DELETE‘ not supported 错误还原：...
docker常见错误
错误1：启动docker镜像时报错：Error response from daemon:...
idea常见错误
错误1：private field ‘xxx‘ is never assigned 按Alt...
pip安装依赖失败
报错如下，通过源不能下载，最后警告pip需升级版本 Requirem...