Ios 致命错误：在展开可选值（lldb）时意外发现nil

我正在尝试添加标记在谷歌地图与长触摸在swift！！！！！ 当我添加下面的代码时，会出现一些错误

class ViewController: UIViewController, CLLocationManagerDelegate, UIGestureRecognizerDelegate {

    var mapView: GMSMapView?
    var locationManager = CLLocationManager()
    var locationMarker: GMSMarker!

    override func viewDidLoad() {
        super.viewDidLoad()

        let longPressRecognizer = UILongPressGestureRecognizer(target: self, action: #selector(ViewController.handleLongPress(_:)))
        self.mapView!.addGestureRecognizer(longPressRecognizer)

        GMSServices.provideAPIKey("AIzaSyBw95wEhcSiSBmPWuYkiK0_IBnZQK-Lm7I")


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

    func locationManager(manager: CLLocationManager, didFailWithError error: NSError) {
        print("Error" + error.description)
    }

    func locationManager(manager: CLLocationManager, didUpdateLocations locations: [CLLocation]) {
        let userLocation = locations.last
        let center = CLLocationCoordinate2D(latitude: userLocation!.coordinate.latitude, longitude: userLocation!.coordinate.longitude)

        let camera = GMSCameraPosition.cameraWithLatitude(userLocation!.coordinate.latitude,
                                                          longitude: userLocation!.coordinate.longitude, zoom: 16)
        let mapView = GMSMapView.mapWithFrame(CGRectZero, camera: camera)
        mapView.myLocationEnabled = true
        mapView.settings.myLocationButton = true
        view = mapView

 // marker with optional position
       let  position = CLLocationCoordinate2DMake(10, 10)
        let marker = GMSMarker(position: position)


        marker.opacity = 0.6
        marker.position = center
        marker.title = "Current Location"
        marker.snippet = ""
        marker.map = mapView
        //mapView.clear()
        //locationManager.stopUpdatingLocation()

        }
    func handleLongPress(recognizer: UILongPressGestureRecognizer)
    {
        if (recognizer.state == UIGestureRecognizerState.Began)
        {
            let longPressPoint = recognizer.locationInView(self.mapView);
            let coordinate = mapView!.projection.coordinateForPoint(longPressPoint )
            //Now you have Coordinate of map add marker on that location

        }}


    }

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在didUpdateLocations方法中会出现错误，因为有时我们似乎无法获取位置，所以在那里传递nil

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因此，您可以使用try-catch-block或使用If-let语法来避免此问题。

问题在于，您使用的地图视图没有初始化

var mapView: GMSMapView?

在viewDidLoad中

    self.mapView!.addGestureRecognizer(longPressRecognizer)

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您可以在viewDidLoad和didUpdateLocations处添加断点，以确切了解nil可选项存在的位置。如果在didUpdateLocations委托方法中，userlocation为nil或NoteError位于view中，则在加载（）时，您正在包装mapView并在其上添加UILongPressGestureRecognitor。您正在didUpdateLocations中初始化mapView。这是你的问题，你会犯错误。使用以下代码：self.view.addgestureRecognitizer（LongPressRecognitizer）didUpdateLocations不会被调用，除非它有位置并且永远不能为零。我应该更改什么？！self.view.addgesturecognizer（longPressRecognizer）var position=坐标var marker=GMSMarker（position:position）marker.title=“Test marker”marker.map=mapview请将此答案标记为true并尝试以下操作：：var tempMapSubView=self.views[0]为！GMSMapView marker.map=类型为“ViewController”的tempMapSubViewValue没有成员“视图”