在iOS 8中，无法在Google地图上显示我的位置

Question

我正在尝试在iOS 8 Swift项目中使用Google Maps for iOS。按照他们的文档说明，我添加了Objective-C桥接头文件并添加了Google Maps SDK。我尝试了这个示例，一切都运作良好。

我需要展示我的当前位置。我在iOS 8模拟器中为自定义位置设置了坐标，并按照这个 StackOverflow 答案中所示修改了代码。下面是它的Swift版本。

import UIKit
import Foundation

class MapViewController: UIViewController {

    @IBOutlet var mapView: GMSMapView!

    var firstLocationUpdate: Bool?

    override func viewDidLoad() {
        super.viewDidLoad()

        let camera = GMSCameraPosition.cameraWithLatitude(-33.86, longitude: 151.20, zoom: 12)
        mapView = GMSMapView.mapWithFrame(CGRectZero, camera: camera)
        mapView.settings.compassButton = true
        mapView.settings.myLocationButton = true

        mapView.addObserver(self, forKeyPath: "myLocation", options: .New, context: nil)

        dispatch_async(dispatch_get_main_queue(), { () -> Void in
            self.mapView.myLocationEnabled = true
        })
        println(mapView.myLocation)
        view = mapView

        let marker = GMSMarker()
        marker.position = CLLocationCoordinate2DMake(-33.86, 151.20)
        marker.title = "Sydney"
        marker.snippet = "Australia"
        marker.map = mapView
    }

    override func observeValueForKeyPath(keyPath: String!, ofObject object: AnyObject!, change: [NSObject : AnyObject]!, context: UnsafeMutablePointer<Void>) {
        firstLocationUpdate = true
        let location = change[NSKeyValueChangeNewKey] as CLLocation
        mapView.camera = GMSCameraPosition.cameraWithTarget(location.coordinate, zoom: 14)
    }
}

我运行了它，但它没有指向我分配的位置。当我用println(mapView.myLocation)打印出位置时，它返回nil。

我认为这是因为在iOS8中，我们必须明确要求用户允许我们获取他们的位置信息。请参见此处。

我已经将NSLocationWhenInUseUsageDescription键添加到我的info.plist中。我的问题是，由于我正在使用Google Maps SDK，如何请求CLLocationManager的权限。我只是添加了下面的代码来检查，但它没有弹出权限对话框。

let locationManager = CLLocationManager()
locationManager.requestWhenInUseAuthorization()

有没有解决办法？还是我们必须等待谷歌更新其SDK？

谢谢。

- Isuru

---

你在异步调度中执行 self.mapView.myLocationEnabled = true 是做什么的？ - Paulw11

Answer 1

您需要保留CLLocationManager，否则它会在呈现授权对话框之前被释放。

注意：请勿删除HTML标签。

class MapViewController: UIViewController {

@IBOutlet var mapView: GMSMapView!

var firstLocationUpdate: Bool?
let locationManager=CLLocationManager()

override func viewDidLoad() {
    super.viewDidLoad()

    self.locationManager.requestWhenInUseAuthorization()

    let camera = GMSCameraPosition.cameraWithLatitude(-33.86, longitude: 151.20, zoom: 12)
    mapView = GMSMapView.mapWithFrame(CGRectZero, camera: camera)
    mapView.settings.compassButton = true
    mapView.settings.myLocationButton = true

    mapView.addObserver(self, forKeyPath: "myLocation", options: .New, context: nil)

    dispatch_async(dispatch_get_main_queue(), { () -> Void in
        self.mapView.myLocationEnabled = true
    })
    println(mapView.myLocation)
    view = mapView

    let marker = GMSMarker()
    marker.position = CLLocationCoordinate2DMake(-33.86, 151.20)
    marker.title = "Sydney"
    marker.snippet = "Australia"
    marker.map = mapView
}

- Paulw11