Swift CCLocation一直返回nil。使用单例

出于某种奇怪的原因，当我第一次尝试运行程序时，它会崩溃，但如果我在模拟器仍在运行时再次运行它，它会正常工作。下面是一些给出问题的代码

class CityList : NSObject, CLLocationManagerDelegate {

// stored properties
var cities: [City]
var currentLocation: CLLocation? = nil
static let sharedInstance = CityList()
static let firstNotif = Notification.Name(rawValue: "test")
static let secondNotif = Notification.Name(rawValue: "test2")
let locationManager = CLLocationManager()

// initializers
override init () {
    cities = [
        City(name: "Medford", state: "Oregon", latitude: 42.3266667, longitude: -122.8744444),
        City(name: "Seattle", state: "Washington", latitude: 47.6063889, longitude: -122.3308333),
        City(name: "Grants, Pass", state: "Oregon", latitude: 42.4391667, longitude: -123.3272222),
        City(name: "Applegate", state: "Oregon", latitude: 42.2570662, longitude: -123.1683833),
        City(name: "San Francisco", state: "California", latitude: 37.775, longitude: -122.4183333)
    ]
    super.init()
    locationManager.delegate = self
    locationManager.requestWhenInUseAuthorization()// request user authorization
    locationManager.requestAlwaysAuthorization()
    locationManager.startUpdatingLocation()
    currentLocation = locationManager.location
    cities.append(City(name: "test", state: "test", location: currentLocation!))
}

---

您必须实现

locationManager（\manager:CLLocationManager，didUpdateLocations locations:[CLLocation]）

以便

CLLocationManagerDelegate

工作，如下所示

import CoreLocation

public class Location: NSObject, CLLocationManagerDelegate {
  private let manager = CLLocationManager()

  override convenience public init() {
    self.init()
    manager.desiredAccuracy = kCLLocationAccuracyThreeKilometers
    manager.delegate = self
    manager.requestWhenInUseAuthorization()
    manager.requestAlwaysAuthorization()
    manager.startUpdatingLocation()
  }

  public func locationManager(_ manager: CLLocationManager, didFailWithError error: Error) {
    print("Error", error)
  }

  public func locationManager(_ manager: CLLocationManager, didUpdateLocations locations: [CLLocation]) {
    guard let location = locations.first else {
      return
    }

    print(location.coordinate.longitude)
    print(location.coordinate.latitude)
  }
}

---

这是一个异步方法。您需要实现

func locationManager（manager:CLLocationManager，didUpdateLocations locations:[CLLocation]）

并检查那里的位置。我已将此函数包含在init下面的模型中。你介意再向我解释一下这个函数的功能吗？它是在接收到位置时调用的，或者如果它发生了变化，那么如果你只需要在使用CLLocation实例方法

requestLocation（）后获取位置，就可以调用它

它避免了不必要的电池使用。我感谢您的意见，但我仍然对新方法有同样的问题。第一次是零，第二次不是