在启动应用程序时尝试用Swift找到用户在Xcode中的位置，但是有可选的错误？

Question

我试图让应用程序找到用户的位置，一旦应用程序已经启动。但是，当我尝试使用viewDidLoad方法并接收到以下错误时，我不断地在requestWhenInUseAuthorization方法中发现一个错误：

    fatal error: unexpectedly found nil while unwrapping an Optional value (lldb)

如果有人能帮我找到解决这个问题的办法，我将非常感激。谢谢!

class ViewController: UIViewController, MKMapViewDelegate, CLLocationManagerDelegate {

@IBOutlet weak var mapView: MKMapView!

var lastLocation = CLLocation()
var locationAuthorizationStatus:CLAuthorizationStatus!
var window: UIWindow?

let locationManager: CLLocationManager!

var seenError : Bool = false
var locationFixAchieved : Bool = false
var locationStatus : NSString = "Not Started"

override func viewDidAppear(animated: Bool) {
    super.viewDidAppear(animated)


    self.initLocationManager()

}


override func viewDidLoad() {
    super.viewDidLoad()




    if (CLLocationManager.locationServicesEnabled()) {
        seenError = false
        locationFixAchieved = false

        locationManager = CLLocationManager()

        self.initLocationManager()

        locationManager.requestWhenInUseAuthorization()

        locationManager.delegate = self
        locationManager.desiredAccuracy = kCLLocationAccuracyBest
        locationManager.startUpdatingLocation()

    }



    mapView.showsUserLocation = true
    mapView.delegate = self
    self.mapView.setUserTrackingMode(MKUserTrackingMode.Follow, animated: true);

}

// Location Manager helper stuff
func initLocationManager() {


    locationManager.requestWhenInUseAuthorization()
}

// Location Manager Delegate stuff

func locationManager(manager: CLLocationManager!, didFailWithError error: NSError!) {
    locationManager.stopUpdatingLocation()
    if ((error) != nil) {
        if (seenError == false) {
            seenError = true
            print(error)
        }
    }
}



override func didReceiveMemoryWarning() {
    super.didReceiveMemoryWarning()
    // Dispose of any resources that can be recreated.
}

}

Answer 1

在didAppear方法之前调用的是didload方法。因此，您的位置管理器尚未初始化。因此，您需要在使用它之前初始化它。