如何快速将地图集中在用户的位置上？

Question

我正在编写一个应用程序，并且我有一个嵌入式地图视图来显示用户的位置。到目前为止，这是我的代码：

class YourCurrentLocation: UIViewController, CLLocationManagerDelegate {

    @IBOutlet weak var mapView: MKMapView!

    var locationManager = CLLocationManager()
    let regionRadius: CLLocationDistance = 1000

    func checkLocationAuthorizationStatus() {
        if CLLocationManager.authorizationStatus() == .AuthorizedWhenInUse {
            mapView.showsUserLocation = true
            centerMapOnLocation(locationManager.location!, map: mapView, radius: regionRadius)
        } else {
            locationManager.requestAlwaysAuthorization() //requestWhenInUseAuthorization()
        }
    }



    func centerMapOnLocation(location: CLLocation, map: MKMapView, radius: CLLocationDistance) {
        let coordinateRegion = MKCoordinateRegionMakeWithDistance(location.coordinate,
            radius * 2.0, radius * 2.0)
        map.setRegion(coordinateRegion, animated: true)
    }


    override func viewDidLoad() {
        super.viewDidLoad()

       // mapView.delegate = self


        if CLLocationManager.locationServicesEnabled()
        {
            //locationManager = CLLocationManager()
            locationManager.delegate = self
            locationManager.requestAlwaysAuthorization()
            locationManager.desiredAccuracy = kCLLocationAccuracyBest
            locationManager.startUpdatingLocation()
            print("location enabled")
            checkLocationAuthorizationStatus()            
        }
        else
        {
            print("Location service disabled");
        }


        // Do any additional setup after loading the view.
    }

}

我还将这两个条目添加到我的 plist 中：

NSLocationAlwaysUsageDescription
NSLocationWhenInUseUsageDescription

在我的 xcode 中，我已经设置模拟英国伦敦的 GPS 数据。

当我运行应用程序时 - 我看到了地图，但没有标记伦敦。我做错了什么？

顺便说一句，我不得不注释掉这一行：

//mapView.delegate = self

在viewDidLoad()，否则我有错误：

Cannot assign value of type YourCurrentLocation to type MKMapViewDelegate

我不确定这是否是问题的一部分。

我想实现当我向用户显示地图以及在该地图上标有他的位置的点时的效果。你能帮我解决这个问题吗？

Answer 1

您的代码的问题在于，当用户授予位置权限时，您试图将地图指向用户的位置，而不是等待CoreLocation 为您提供实际的用户位置。 您需要使用CLLocationManagerDelegate 方法locationManager(_:didUpdateLocations:) 来通知您何时获得用户的实际位置，并且那里您可以将地图设置为指向用户的位置。

class ViewController: UIViewController, CLLocationManagerDelegate {

    @IBOutlet var mapView: MKMapView!
    var locationManager: CLLocationManager?

    override func viewDidLoad() {
        super.viewDidLoad()

        locationManager = CLLocationManager()
        locationManager!.delegate = self

        if CLLocationManager.authorizationStatus() == .AuthorizedWhenInUse {
            locationManager!.startUpdatingLocation()
        } else {
            locationManager!.requestWhenInUseAuthorization()
        }
    }

    func locationManager(manager: CLLocationManager, didChangeAuthorizationStatus status: CLAuthorizationStatus) {


        switch status {
        case .NotDetermined:
            print("NotDetermined")
        case .Restricted:
            print("Restricted")
        case .Denied:
            print("Denied")
        case .AuthorizedAlways:
            print("AuthorizedAlways")
        case .AuthorizedWhenInUse:
            print("AuthorizedWhenInUse")
            locationManager!.startUpdatingLocation()
        }
    }

    func locationManager(manager: CLLocationManager, didUpdateLocations locations: [CLLocation]) {

        let location = locations.first!
        let coordinateRegion = MKCoordinateRegionMakeWithDistance(location.coordinate, 500, 500)
        mapView.setRegion(coordinateRegion, animated: true)
        locationManager?.stopUpdatingLocation()
        locationManager = nil
    }

    func locationManager(manager: CLLocationManager, didFailWithError error: NSError) {
        print("Failed to initialize GPS: ", error.description)
    }
}