如何使用Google Maps SDK for Swift查找用户的位置?

所以我正在尝试获取它,所以我打开应用程序,它从用户的位置开始。问题是我在输出框中得到“用户位置未知”。如下面的代码所示,我启用了位置功能,所以我想知道是否是其他原因导致了这个问题。谢谢你的帮助。

import UIKit
import GoogleMaps

class ViewController: UIViewController {

    override func viewDidLoad() {
        super.viewDidLoad()
        // Do any additional setup after loading the view, typically from a nib.

        let camera = GMSCameraPosition.cameraWithLatitude(-33.86,
                                                          longitude: 151.20, zoom: 6)
        let mapView = GMSMapView.mapWithFrame(CGRectZero, camera: camera)
        mapView.accessibilityElementsHidden = false
        mapView.myLocationEnabled = true
        self.view = mapView

        if let mylocation = mapView.myLocation {
            print("User's location: \(mylocation)")
        } else {
            print("User's location is unknown")
        }
        let marker = GMSMarker()
        marker.position = CLLocationCoordinate2DMake(-33.86, 151.20)
        marker.title = "Sydney"
        marker.snippet = "Australia"
        marker.map = mapView

    }

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


}