ios - 定位服务作为 Swift 中的单例，卡在 "When In Use"上

Question

我正在编写一个需要“始终定位”的应用程序，并且我决定使用单例来保持跟踪事件，因为即使在后台，我大多数时间也需要定位服务。

当我在 iPhone 上运行该应用程序时，控制台显示位置服务处于“使用时”模式，并且我的协议(protocol)无法从 LocationManager 获取位置更新。

我的 Singleton 有什么问题(我是 Swift 新手，请清楚地回答。使用 Singleton 进行位置服务是个好主意吗？

LocationService.swift(已更新)

import Foundation
import CoreLocation

protocol LocationServiceDelegate {
    func onLocationUpdate(location: CLLocation)
    func onLocationDidFailWithError(error: Error)
}

class LocationService: NSObject, CLLocationManagerDelegate {

    public static let shared = LocationService()

    var delegate: LocationServiceDelegate?
    var locationManager: CLLocationManager!
    var currentLocation: CLLocation!

    private override init() {
        super.init()
        self.initializeLocationServices()
    }

    func initializeLocationServices() {
        self.locationManager = CLLocationManager()
        self.locationManager.desiredAccuracy = kCLLocationAccuracyBest
        self.locationManager.requestAlwaysAuthorization()
        self.locationManager.pausesLocationUpdatesAutomatically = false
        self.locationManager.delegate = self
        self.locationManager.startUpdatingLocation()
    }

    func locationManager(_ manager: CLLocationManager, didChangeAuthorization status: CLAuthorizationStatus) {
        switch status {
            case .restricted:
                print("Location access was restricted.")
            case .denied:
                print("User denied access to location.")
            case .notDetermined:
                self.locationManager.requestAlwaysAuthorization()
            case .authorizedAlways: fallthrough
            case .authorizedWhenInUse:
                print("User choosed locatiom when app is in use.")
            default:
                print("Unhandled error occured.")
        }
    }

    func locationManager(_ manager: CLLocationManager, didUpdateLocations locations: [CLLocation]) {
        self.currentLocation = locations.last!
        locationChanged(location: currentLocation)
    }

    private func locationChanged(location: CLLocation) {
        guard let delegate = self.delegate else {
            return
        }
        delegate.onLocationUpdate(location: location)
    }

    func locationManager(_ manager: CLLocationManager, didFailWithError error: Error) {
        self.locationManager.stopUpdatingLocation()
        locationFailed(error: error)
    }

    private func locationFailed(error: Error) {
        guard let delegate = self.delegate else {
            return
        }
        delegate.onLocationDidFailWithError(error: error)
    }
}

然后我初始化单例:

AppDelegate.swift

 let locationService = LocationService.shared

然后我的 View 符合我的协议(protocol):

ViewController.swift

 extension ViewController: LocationServiceDelegate {
    func onLocationUpdate(location: CLLocation) {
        print("Current Location : \(location)")
    }

    func onLocationDidFailWithError(error: Error) {
        print("Error while trying to update device location : \(error)")
    }
}

Answer 1

是的，您可以使用单例来达到您的目的。您可以在实现中检查几件事:

• locationManager.pausesLocationUpdatesAutomatically = false。
• 启用位置更新的后台模式。
• 当应用移至后台时切换到重要位置更新。