locationManager.location 返回 nil

Question

我正在使用swift4.2并且Xcode 10我正在尝试使iOS应用程序使用位置服务，但它给了我一个例外：
Fatal error: Unexpectedly found nil while unwrapping an Optional value

所以我试图检查位置是否返回 nil 所以我复制我的代码并打印位置并返回null，我Xcode从产品>方案>编辑方案>默认位置和调试区域中的检查位置模拟位置，并模拟到位置我选择任何一个知道问题所在吗？

import CoreLocation

class LocationVC: UIViewController,CLLocationManagerDelegate {

    let locationManager = CLLocationManager()
    var currentlocation:CLLocation!

    override func viewDidLoad() {
        super.viewDidLoad()
        locationManager.delegate = self
        locationManager.desiredAccuracy = kCLLocationAccuracyBest
        locationManager.requestWhenInUseAuthorization()
        locationManager.startMonitoringSignificantLocationChanges()
   }

    override func viewDidAppear(_ animated: Bool) {
        super.viewDidAppear(animated)
        authorizelocationstates()
    }

    func authorizelocationstates(){
        if CLLocationManager.authorizationStatus() == .authorizedWhenInUse {
            currentlocation = locationManager.location
            print(currentlocation)
        }
        else{
            locationManager.requestWhenInUseAuthorization()
            authorizelocationstates()
        }
        }

Answer 1

我已经运行了您的代码，我刚刚在文件中添加了缺少的密钥Privacy - Location When In Use Usage Descriptioninfo.plist。

我对您的代码进行了一些更改并获得了nil价值，因为方法被多次调用，并且当用户授予权限并再次调用方法并打印位置详细信息时，但事实仍然是locationManager可变的，还没有用户位置数据。

在locationManager委托didUpdateLocations调用时获取位置详细信息

我对您的代码进行了一些更改：

import UIKit
import CoreLocation
class ViewController: UIViewController,CLLocationManagerDelegate {
    var locationManager = CLLocationManager()
    var currentlocation:CLLocation!



    override func viewDidAppear(_ animated: Bool) {
        super.viewDidAppear(animated)
     //   authorizelocationstates()
    }

    func authorizelocationstates(){
        if CLLocationManager.authorizationStatus() == .authorizedWhenInUse {
            currentlocation = locationManager.location
            print(currentlocation)
        }
        else{
            // Note : This function is overlap permission
            //  locationManager.requestWhenInUseAuthorization()
           //  authorizelocationstates()
        }
    }
    func locationManager(_ manager: CLLocationManager, didUpdateLocations locations: [CLLocation]) {
        locationManager = manager
        // Only called when variable have location data
        authorizelocationstates()
    }
    override func viewDidLoad() {
        super.viewDidLoad()

        locationManager.delegate = self
        locationManager.desiredAccuracy = kCLLocationAccuracyBest
        // Get Location Permission one time only
        locationManager.requestWhenInUseAuthorization()
        // Need to update location and get location data in locationManager object with delegate
        locationManager.startUpdatingLocation()
        locationManager.startMonitoringSignificantLocationChanges()

    }

}

希望它会帮助你。