ios - 无法在 Swift 2 中将类型 '__NSCFNumber' 的值转换为 'NSString'

Question

我正在使用 CLLocationmanager 从 app delegate 获取纬度和经度通过使用以下代码:

  class AppDelegate: UIResponder, UIApplicationDelegate, CLLocationManagerDelegate{


    var window: UIWindow?

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


    func application(application: UIApplication, didFinishLaunchingWithOptions launchOptions: [NSObject: AnyObject]?) -> Bool {
    initLocationManager();
        return true
    }

    func initLocationManager() {
        seenError = false
        locationFixAchieved = false
        locationManager = CLLocationManager()
        locationManager.delegate = self
        CLLocationManager.locationServicesEnabled()
        locationManager.desiredAccuracy = kCLLocationAccuracyBest

        locationManager.requestAlwaysAuthorization()
        locationManager.startUpdatingLocation()
    }

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

    func locationManager(manager: CLLocationManager, didUpdateLocations locations: [CLLocation]) {
        if (locationFixAchieved == false) {
            locationFixAchieved = true
            var locationArray = locations as NSArray
            var locationObj = locationArray.lastObject as! CLLocation
            var coord = locationObj.coordinate
            NSUserDefaults.standardUserDefaults().setObject(coord.latitude, forKey: "latitude")



            NSUserDefaults.standardUserDefaults().setObject(coord.longitude, forKey: "longitude")
            NSUserDefaults.standardUserDefaults().synchronize()
            print(coord.latitude)
            print(coord.longitude)
        }
    }

在使用代码在 map View 中使用来自 nsuserdefaults 的值时

   latitude = (NSUserDefaults.standardUserDefaults().objectForKey("latitude") as? NSString)! as String
        longitude = (NSUserDefaults.standardUserDefaults().objectForKey("longitude") as? NSString)! as String
        let latitude1 = (latitude as NSString).doubleValue
        let longitude1 = (longitude as NSString).doubleValue
        let location = CLLocationCoordinate2D(
            latitude: latitude1,
            longitude: longitude1
        )

我在 latitude = (NSUserDefaults.standardUserDefaults().objectForKey("latitude") as?NSString) 收到错误消息“无法将‘__NSCFNumber’ (0x1944fb9f8) 类型的值转换为‘NSString’”!作为字符串

Answer 1

在 AppDelegate 中使用此代码像这样在 NSUserDefaults 中保存纬度和经度

func locationManager(manager: CLLocationManager, didUpdateLocations locations: [CLLocation]) {
    if (locationFixAchieved == false) {
        locationFixAchieved = true
        let locationArray = locations as NSArray
        let locationObj = locationArray.lastObject as! CLLocation
        let coord = locationObj.coordinate
        NSUserDefaults.standardUserDefaults().setDouble(coord.latitude, forKey: "latitude")
        NSUserDefaults.standardUserDefaults().setDouble(coord.longitude, forKey: "longitude")
        NSUserDefaults.standardUserDefaults().synchronize()
        print(coord.latitude)
        print(coord.longitude)
    }
}

为了获取值，请在 View Controller 文件中使用此代码

 override func viewDidLoad() {
    super.viewDidLoad()

    // Do any additional setup after loading the view.
    let latitude2 = NSUserDefaults.standardUserDefaults().objectForKey("latitude")
    let longitude2 = NSUserDefaults.standardUserDefaults().objectForKey("longitude")
    let latitude1  = latitude2!.doubleValue
    let longitude1 = longitude2!.doubleValue
    let location = CLLocationCoordinate2D(
        latitude: latitude1,
        longitude: longitude1
    )


}