myLocationEnabled - 在展开时出乎意料地发现了nil

时间:2016-02-06 12:23:43

标签: ios swift mkmapview cllocationmanager

我只是想使用GoogleMaps API在我的MapViewController中获取用户位置。 我到处都环顾四周,无法弄清楚为什么我会不断发生致命的错误:在这个特殊的地方,在展开和意外值时意外地发现了nil。

这是我的代码:

class MapViewController: UIViewController {

    let locationManager = CLLocationManager()
    @IBOutlet weak var mapView: GMSMapView!

    override func viewDidLoad() {
        super.viewDidLoad()

        locationManager.delegate = self
        locationManager.requestWhenInUseAuthorization()

        let camera = GMSCameraPosition.cameraWithLatitude(-34.9290, longitude:138.6010, zoom:10)
        let mapView = GMSMapView.mapWithFrame(CGRectZero, camera:camera)
        mapView.mapType = kGMSTypeNormal
        print("Calling addMarker")
        // addMarker()
        self.view = mapView
        }

extension MapViewController: CLLocationManagerDelegate {
    func locationManager(manager: CLLocationManager, didChangeAuthorizationStatus status: CLAuthorizationStatus) {
        if status == .AuthorizedWhenInUse {
            locationManager.startUpdatingLocation()
            mapView.myLocationEnabled = true
            mapView.settings.myLocationButton = true
        }
    }

    func locationManager(manager: CLLocationManager, didUpdateLocations locations: [CLLocation]) {
        if let location = locations.first {
            mapView.camera = GMSCameraPosition(target: location.coordinate, zoom: 15, bearing: 0, viewingAngle: 0)
            locationManager.stopUpdatingLocation()
        }
    }
}

这是我收到错误的地方:

!(http://imgur.com/qxxf0SV

我知道mapView.myLocationEnabled正在返回,但不知道为什么/如何。

1 个答案:

答案 0 :(得分:0)

很可能是mapView是nil,而不是mapView.myLocationEnabled。当你遇到崩溃时,请尝试以下lldb命令:

po mapView

这将完全告诉你。

didChangeAuthorizationStatus委托可能是从后台调用或在视图完成之前调用的。您应该将这些扩展移动到AppDelegate中。