如何在swift中將地圖置於用戶位置的中心？

Question

我正在編寫一個應用程序，我有一個嵌入式mapview來顯示用戶的位置。 到目前為止這是我的代碼：

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.
    }

}

我還在我的plist中添加了兩個條目：

NSLocationAlwaysUsageDescription
NSLocationWhenInUseUsageDescription

而且在我的xcode中，我已經開始在英國倫敦模擬GPS數據。

當我運行應用程序時 - 我看到地圖，但倫敦沒有標記。 我究竟做錯了什么？

順便說一句，我不得不評論這一行：

//mapView.delegate = self

在viewDidLoad() ，否則我有錯誤：

Cannot assign value of type YourCurrentLocation to type MKMapViewDelegate

而且我不確定這是否是問題的一部分。

我希望在顯示到用戶地圖和該地圖上標有其位置的點時實現效果。 你能幫幫我嗎？

Answer 1

代碼的問題在於，當用戶提供位置權限時，您試圖將地圖指向用戶的位置，而不是等待CoreLocation為您提供實際的用戶位置。 您需要使用CLLocationManagerDelegate方法locationManager(_:didUpdateLocations:)當你得到了用戶的實際位置通知的，在那里你可以設置映射指向用戶的位置。

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)
    }
}