我想使用Swift获取位置的当前经度和纬度，并通过标签显示它们。我尝试执行此操作，但标签上没有任何显示。

import UIKit
import CoreLocation
class ViewController: UIViewController, CLLocationManagerDelegate{

    @IBOutlet weak var longitude: UILabel!
    @IBOutlet weak var latitude: UILabel!
    let locationManager = CLLocationManager()

    override func viewDidLoad() {
        super.viewDidLoad()
        if (CLLocationManager.locationServicesEnabled()) {
            locationManager.delegate = self
            locationManager.desiredAccuracy = kCLLocationAccuracyBest
            locationManager.requestWhenInUseAuthorization()
            locationManager.startUpdatingLocation()
        } else {
            println("Location services are not enabled");
        }
    }

    // MARK: - CoreLocation Delegate Methods

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

    func locationManager(manager: CLLocationManager!, didUpdateLocations locations: [AnyObject]!) {
        var locationArray = locations as NSArray
        var locationObj = locationArray.lastObject as CLLocation
        var coord = locationObj.coordinate
        longitude.text = coord.longitude
        latitude.text = coord.latitude
        longitude.text = "\(coord.longitude)"
        latitude.text = "\(coord.latitude)"
    }
}