后台位置更新

Question

我正在构建一个带有位置服务的应用程序。

我正在使用用户当前位置来获取用户周围的对象。目前运行良好。唯一的问题是，我想在后台为具有 "signficantLocationChanges" 的用户创建本地通知，但是当应用程序从具有 applicationDidFinishLaunching(_:) 功能的 AppDelegate 启动时，launchOptions 对象是 nil.

我想获取后台更新并发出 HTTP API 请求，根据响应，我将创建本地通知。

这是我的 AppDelegate class:

import UIKit
import UserNotifications
import CoreLocation

@UIApplicationMain
class AppDelegate: UIResponder, UIApplicationDelegate {

    var window: UIWindow?
    var locationManager: LocationManager?

    func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplication.LaunchOptionsKey: Any]?) -> Bool {

        // Checking this because if the app is started for location updates,
        // no need to setup app for UI
        if let _ = launchOptions?[.location] {
            locationManager = LocationManager()
            locationManager?.delegate = self
            locationManager?.getCurrentLocation()
            return true
        }

        attemptToRegisterForNotifications(application: application)

        if #available(iOS 13, *) { } else {
            app.start()
        }

        return true
    }

    // MARK: UISceneSession Lifecycle
    @available(iOS 13.0, *)
    func application(_ application: UIApplication, configurationForConnecting connectingSceneSession: UISceneSession, options: UIScene.ConnectionOptions) -> UISceneConfiguration {
        // Called when a new scene session is being created.
        // Use this method to select a configuration to create the new scene with.
        return UISceneConfiguration(name: "Default Configuration", sessionRole: connectingSceneSession.role)
    }

    @available(iOS 13.0, *)
    func application(_ application: UIApplication, didDiscardSceneSessions sceneSessions: Set<UISceneSession>) {
        // Called when the user discards a scene session.
        // If any sessions were discarded while the application was not running, this will be called shortly after application:didFinishLaunchingWithOptions.
        // Use this method to release any resources that were specific to the discarded scenes, as they will not return.
    }

    func applicationDidBecomeActive(_ application: UIApplication) {
        UNUserNotificationCenter.current().removeAllDeliveredNotifications()
    }
}

extension AppDelegate: LocatableOutputProtocol {
    func didGetCurrentLocation(latitude: Double, longitude: Double) {
        UNUserNotificationCenter.current().getNotificationSettings(completionHandler: { (settings) in
            if settings.authorizationStatus == .authorized {
                let content = UNMutableNotificationContent()
                content.title = "\(Date().timeIntervalSince1970)"

                let trigger = UNTimeIntervalNotificationTrigger(timeInterval: 5, repeats: false)

                let request = UNNotificationRequest(identifier: "\(Date().timeIntervalSince1970)", content: content, trigger: trigger)

                UNUserNotificationCenter.current().add(request) { _ in

                }
            }
        })
    }

    func failedGetCurrentLocation(error: Error) {
        print(error)
    }
}

extension AppDelegate: UNUserNotificationCenterDelegate {

    private func attemptToRegisterForNotifications(application: UIApplication) {
        UNUserNotificationCenter.current().delegate = self

        let authOptions: UNAuthorizationOptions = [.alert, .badge, .sound]
        UNUserNotificationCenter.current().requestAuthorization(options: authOptions, completionHandler: { granted, error in
            if let error = error {
                print("failed to get auth", error)
                return
            }
            if granted {
                DispatchQueue.main.async {
                    application.registerForRemoteNotifications()
                }
            } else {
                print("NO AVAIL FOR NOTIFS")
            }
        })
    }

    func userNotificationCenter(_ center: UNUserNotificationCenter, willPresent notification: UNNotification, withCompletionHandler completionHandler: @escaping (UNNotificationPresentationOptions) -> Void) {
        completionHandler(.alert)
    }
}

我也有一个习惯 LocationManager class:

import CoreLocation

final class LocationManager: NSObject, Locatable {
    weak var delegate: LocatableOutputProtocol?

    var locationManager: CLLocationManager

    override init() {
        locationManager = CLLocationManager()
        super.init()

        let authStatus = CLLocationManager.authorizationStatus()
        if CLLocationManager.locationServicesEnabled() {
            if (authStatus == .authorizedAlways || authStatus == .authorizedWhenInUse) {
                locationManager.delegate = self
                locationManager.startUpdatingLocation()
                locationManager.startMonitoringSignificantLocationChanges()
                locationManager.allowsBackgroundLocationUpdates = true
                locationManager.desiredAccuracy = kCLLocationAccuracyBest
            } else {
                locationManager.requestAlwaysAuthorization()
                print("we dont have permission")
            }
        } else {

        }
    }

    func getCurrentLocation() {
        locationManager.startUpdatingLocation()
    }
}

extension LocationManager: CLLocationManagerDelegate {
    func locationManager(_ manager: CLLocationManager, didUpdateLocations locations: [CLLocation]) {
        if let coordinates = locations.first?.coordinate {
            locationManager.stopUpdatingLocation()
            self.delegate?.didGetCurrentLocation(latitude: coordinates.latitude, longitude: coordinates.longitude)
        }
    }

    func locationManager(_ manager: CLLocationManager, didFailWithError error: Error) {
        self.delegate?.failedGetCurrentLocation(error: error)
    }

    func locationManager(_ manager: CLLocationManager, didChangeAuthorization status: CLAuthorizationStatus) {
        print("status changed")
        if (status == .authorizedAlways || status == .authorizedWhenInUse) {
            print("we got permission")
        } else {
            print("nope")
        }
    }
}

我正在尝试通过在 Xcode 上使用 Wait for executable to be launched 创建新模式并在模拟器的调试菜单上使用高速公路行驶来调试它。也用真机测试过。

我错过了什么？

Answer 1

@onurgenes 您需要在位置管理器初始化部分使用 NotificationCenter，如下所示，

import CoreLocation

    final class LocationManager: NSObject, Locatable {
        weak var delegate: LocatableOutputProtocol?

        var locationManager: CLLocationManager

        override init() {

            NotificationCenter.default.addObserver(self, selector: #selector(applicationDidEnterBackgroundActive(_:)), name: UIApplication.didEnterBackgroundNotification, object: nil)

            NotificationCenter.default.addObserver(self, selector: #selector(applicationWillEnterForegroundActive(_:)), name: UIApplication.willEnterForegroundNotification, object: nil)

            locationManager = CLLocationManager()
            super.init()

            let authStatus = CLLocationManager.authorizationStatus()
            if CLLocationManager.locationServicesEnabled() {
                if (authStatus == .authorizedAlways || authStatus == .authorizedWhenInUse) {
                    locationManager.delegate = self
                    locationManager.startUpdatingLocation()
                    locationManager.startMonitoringSignificantLocationChanges()
                    locationManager.allowsBackgroundLocationUpdates = true
                    locationManager.desiredAccuracy = kCLLocationAccuracyBest
                } else {
                    locationManager.requestAlwaysAuthorization()
                    print("we dont have permission")
                }
            } else {

            }
        }

        func getCurrentLocation() {
            locationManager.startUpdatingLocation()
        }
    }

    extension LocationManager: CLLocationManagerDelegate {
        func locationManager(_ manager: CLLocationManager, didUpdateLocations locations: [CLLocation]) {
            if let coordinates = locations.first?.coordinate {
                locationManager.stopUpdatingLocation()
                self.delegate?.didGetCurrentLocation(latitude: coordinates.latitude, longitude: coordinates.longitude)
            }
        }

        func locationManager(_ manager: CLLocationManager, didFailWithError error: Error) {
            self.delegate?.failedGetCurrentLocation(error: error)
            self.locationManager.stopMonitoringSignificantLocationChanges()
        }

        func locationManager(_ manager: CLLocationManager, didChangeAuthorization status: CLAuthorizationStatus) {
            print("status changed")
            if (status == .authorizedAlways || status == .authorizedWhenInUse) {
                print("we got permission")
            self.locationManager.startMonitoringSignificantLocationChanges()
            } else {
                print("nope")
            }
        }
    }


        @objc private func applicationDidEnterBackgroundActive (_ notification: Notification) {
                self.locationManager.startMonitoringSignificantLocationChanges()
        }

        @objc private func applicationWillEnterForegroundActive (_ notification: Notification) {
            self.locationManager.startUpdatingLocation()
        }

您需要在 AppDelegate class 上使用此 LocationManager class 以进行初始化。我希望它能帮助您实现所需的输出。

Answer 2

@onurgenes，如果你从你的项目中添加一个真实的代码，首先，你如何从这里开始任何位置更新？

    if let _ = launchOptions?[.location] {
        locationManager = LocationManager()
        locationManager?.delegate = self
        locationManager?.getCurrentLocation()
        return true
    }

当应用程序第一次启动时 launchOptions 将是 nil，而你的 LocationManager() 甚至还没有启动，所以你的任何位置监控和更新将不起作用（也许你在 app.start() 有一些代码，但现在它看起来像一个错误）。

第二件事 - 在您的示例中，您使用的是定位监控：

    locationManager.startUpdatingLocation()
    locationManager.startMonitoringSignificantLocationChanges()

所以这里您的位置管理器只处理 significantLocationChanges()。如果您想同时使用它们 - 您应该切换它（在 didBecomeActiveNotification 和 didEnterBackgroundNotification 处）或按照 Apple 的建议创建位置管理器的不同实例。

第三个——你的问题。让我们更详细地寻找这部分：

locationManager = LocationManager()
locationManager?.delegate = self
locationManager?.getCurrentLocation()

正如我提到的 - 在 LocationManager() 你开始监控位置：

locationManager.startUpdatingLocation()
locationManager.startMonitoringSignificantLocationChanges()

这就是您所需要的 - 显着的位置变化。但是在你用 locationManager.startUpdatingLocation() 调用 getCurrentLocation() 之后，你 'rewrite' 你的监控，这就是你没有从它那里得到任何更新的原因。

此外，请记住：

重要位置仅在出现设备位置的重大变化，（实验性的建立500米以上）
重要位置非常不准确（对我来说有时高达 900 米）。通常重要的位置仅用于唤醒应用程序并重新启动定位服务。
在您的应用从位置更改中唤醒后通知，你有少量的时间（大约 10 秒），所以如果您需要更多时间将位置发送到服务器你应该要求更多的时间 beginBackgroundTask(withName:expirationHandler:)

希望我的回答对您有所帮助。编码愉快！

后台位置更新

Background Location Updates

core-location

cllocationmanager

ios

swift

ios13