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Swift:谷歌 Map 代码抛出零例外

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我有以下代码,它应该基本上检测位置(如果位置服务打开),然后返回上一页并显示坐标(单击按钮时) .

@IBOutlet var mapView:GMSMapView!//在Storyboard上添加Google Map检查var locationManager:CLLocationManager! var viewController:ViewController! //保存前一个控制器的对象以返回该位置

override func viewDidLoad() {
    super.viewDidLoad()
    // Do any additional setup after loading the view.
    locationManager = CLLocationManager() // Intialize the location manager
    locationManager.delegate = self

}


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

//Methos to change the MApType
@IBAction func changeMaptoEarthView()
{
    self.mapView.mapType = kGMSTypeSatellite
}

@IBAction func changeMaptoMapView()
{
    self.mapView.mapType = kGMSTypeNormal
}
//Method to get UserLocation
@IBAction func sendLocationtoPreviousView()
{
    viewController.locationRecieved(locationManager.location)
    self.performSegueWithIdentifier("backSegue", sender: nil)
}

@IBAction func addUserLocation() //Detect location click event
{
    if(CLLocationManager.authorizationStatus() == .AuthorizedWhenInUse) // If already have location access
    {
        locationManager.startUpdatingLocation()
    }
    else if (CLLocationManager.authorizationStatus() == .Denied)// If location access is denied in setting
    {
        UIAlertView(title: "Permission", message: "Please allow location services in setting", delegate: nil, cancelButtonTitle: "ok").show()
    }
    else
    {
        locationManager.requestWhenInUseAuthorization() // Ask user permission if permission not given
    }
}

//CLLocation Manager Delegate methoda
func locationManager(manager: CLLocationManager!, didChangeAuthorizationStatus status: CLAuthorizationStatus) {

    if status == .AuthorizedWhenInUse {

        locationManager.startUpdatingLocation()

    }
}


func locationManager(manager: CLLocationManager!, didUpdateLocations locations: [AnyObject]!) {
    if let location = locations.first as? CLLocation {

        self.mapView.clear() // clear all overlay on Map
        self.mapView.camera = GMSCameraPosition(target: location.coordinate, zoom: 15, bearing: 0, viewingAngle: 0)
        // Adding pin on Current location
        var marker = GMSMarker()
        marker.position = location.coordinate
        marker.snippet = "My Location"
        marker.appearAnimation = kGMSMarkerAnimationPop
        marker.map = mapView

        locationManager.stopUpdatingLocation()
    }
}

该应用程序在模拟器中工作,直到我说回去,然后它在此行抛出零错误消息:

viewController.locationRecieved(locationManager.location)

可能是什么原因?我可以看到 Map 上的图钉虽然 Map 没有显示任何图形,除了下面的谷歌徽标

2 回答

  • 2

    CLLocationManager 上的 location 属性是可选的 - 意味着它可以是nil . 根据文档,如果没有检索到位置数据,那将是零 .

    您没有显示如何定义 viewController.locationRecieved ,但我的猜测是您已将 CLLocation 参数配置为隐式展开的可选项(即,使用"!") . 将nil传递给这样的参数会导致崩溃 .

  • 0

    如果您在视图(GMSMapView的子类)中没有看到 Map 图形,这是因为Google Map API密钥,可能您尚未在应用委托中设置它或未正确设置!

    确保您已使用Google应用套件ID和您的帐户设置了正确的Google API密钥 . 你必须在app app中设置下面的代码,做didFinishLaunchingWithOptions函数:

    import GoogleMaps
    
    func application(application: UIApplication, didFinishLaunchingWithOptions launchOptions: [NSObject: AnyObject]?) -> Bool {
              GMSServices.provideAPIKey("your API Key")
    }
    

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