MapKit缩放到用户当前位置

Question

我试图简单地在地图上显示用户的位置,但是我需要在应用程序启动时,地图应该缩放到当前位置,但我不知道为什么地图根本不会缩放,它是这样的:

这是代码:

class MapViewController: UIViewController, CLLocationManagerDelegate, MKMapViewDelegate {

    @IBOutlet weak var mapView: MKMapView!
    var locationManager = CLLocationManager()

    override func viewDidLoad() {
        super.viewDidLoad()

        mapView.delegate = self
        mapView.showsUserLocation = true
        locationManager.desiredAccuracy = kCLLocationAccuracyBest
        locationManager.requestWhenInUseAuthorization()
        locationManager.delegate = self
        DispatchQueue.main.async {
            self.locationManager.startUpdatingLocation()
        }
    }

    func locationManager(manager: CLLocationManager!, didUpdateLocations locations: [AnyObject]!) {
        let location = locations.last as! CLLocation
        let center = CLLocationCoordinate2D(latitude: location.coordinate.latitude, longitude: location.coordinate.longitude)
        var region = MKCoordinateRegion(center: center, span: MKCoordinateSpan(latitudeDelta: 0.1, longitudeDelta: 0.1))
        region.center = mapView.userLocation.coordinate
        mapView.setRegion(region, animated: true)
    }

Answer 1

我遇到了类似的问题,浪费了4天思考什么是错的.最后通过在viewDidLoadMethod中创建这些代码行来解决:

    //Zoom to user location
    let noLocation = CLLocationCoordinate2D()
    let viewRegion = MKCoordinateRegionMakeWithDistance(noLocation, 200, 200)
    mapView.setRegion(viewRegion, animated: false)
    mapView.showsUserLocation = true

在ViewDidLoadMethod中添加以下新更改代码:

override func viewDidLoad() {

    super.viewDidLoad()

    let locationManager = CLLocationManager()
    locationManager.delegate = self
    locationManager.desiredAccuracy = kCLLocationAccuracyBest

    // Check for Location Services
    if (CLLocationManager.locationServicesEnabled()) {
        locationManager.requestAlwaysAuthorization()
        locationManager.requestWhenInUseAuthorization()
    }

    //Zoom to user location
    if let userLocation = locationManager.location?.coordinate {
        let viewRegion = MKCoordinateRegionMakeWithDistance(userLocation, 200, 200)
        mapView.setRegion(viewRegion, animated: false)
    }

    self.locationManager = locationManager

    DispatchQueue.main.async {
        self.locationManager.startUpdatingLocation()
    }

}

希望这有助于解决您的问题.如果有任何进一步的问题,请随时发表评论.谢谢

Answer 2

这是Swift 3的另一种方法,XCode 8.2.首先,写出一个辅助函数:

let homeLocation = CLLocation(latitude: 37.6213, longitude: -122.3790)
let regionRadius: CLLocationDistance = 200
func centerMapOnLocation(location: CLLocation)
{
    let coordinateRegion = MKCoordinateRegionMakeWithDistance(location.coordinate,
                                           regionRadius * 2.0, regionRadius * 2.0)
    mapView.setRegion(coordinateRegion, animated: true)
}

然后,打进来 viewDidLoad()

mapView.showsUserLocation = true
centerMapOnLocation(location: homeLocation)

这将启动应用程序,并在变量中指定的位置放大.

Answer 3

在Swift 4.2中，此代码进行了更改。现在是这样工作的：

import UIKit
import MapKit
import CoreLocation

class MapVC: UIViewController, CLLocationManagerDelegate, MKMapViewDelegate {

    @IBOutlet weak var mapView: MKMapView!
    var locationManager = CLLocationManager()
    let authorizationStatus = CLLocationManager.authorizationStatus()
    let regionRadius: Double = 1000

    override func viewDidLoad() {
        super.viewDidLoad()
        mapView.delegate = self
        locationManager.delegate = self
        configureLocationServices()
    }

    func centerMapOnUserLocation() {
        guard let coordinate = locationManager.location?.coordinate else {return}
        let coordinateRegion = MKCoordinateRegion(center: coordinate, latitudinalMeters: regionRadius, longitudinalMeters: regionRadius)
        mapView.setRegion(coordinateRegion, animated: true)
    }

    func configureLocationServices() {
        if authorizationStatus == .notDetermined {
            locationManager.requestAlwaysAuthorization()
        } else {
            return
        }
    }

    func locationManager(_ manager: CLLocationManager, didChangeAuthorization status: CLAuthorizationStatus) {
        centerMapOnUserLocation()
    }

}