如何使用 mapkit 和 swift 在设定位置覆盖一个圆圈

Question

我无法弄清楚如何在与用户位置不同的所需位置显示透明圆形或矩形。 我是 mapkit 的初学者，所以提前致谢。

class FirstViewController: UIViewController, MKMapViewDelegate, CLLocationManagerDelegate
{

@IBOutlet weak var mapView: MKMapView!

let locationManager = CLLocationManager()

override func viewDidLoad()
{
    super.viewDidLoad()

    self.locationManager.delegate = self
    self.locationManager.desiredAccuracy = kCLLocationAccuracyBest
    self.locationManager.requestAlwaysAuthorization()
    self.locationManager.startUpdatingLocation()
    self.mapView.showsUserLocation = true

}

func locationManager(manager: CLLocationManager, didUpdateLocations locations: [CLLocation])
{
    let location = locations.last
    let center = CLLocationCoordinate2D(latitude: location!.coordinate.latitude, longitude: location!.coordinate.longitude)
    let region = MKCoordinateRegion(center: center, span: MKCoordinateSpan(latitudeDelta: 1, longitudeDelta: 1))
    self.mapView.setRegion(region, animated: true)
    self.locationManager.stopUpdatingLocation()//
}

func locationManager(manager: CLLocationManager, didFailWithError error: NSError)
{
    print("Errors: " + error.localizedDescription)
}

}

Answer 1

这已更新为支持 Swift 4.2。 提供了一些评论来解释我所做的几个选择。

import UIKit
import MapKit

class Map: UIViewController {
    var mapView = MKMapView()

    func setup() {
        // Assign delegate here. Can call the circle at startup,
        // or at a later point using the method below.
        // Includes <# #> syntax to simplify code completion.
        mapView.delegate = self
        showCircle(coordinate: <#CLLocationCoordinate2D#>,
                   radius: <#CLLocationDistance#>)
    }

    // Radius is measured in meters
    func showCircle(coordinate: CLLocationCoordinate2D,
                    radius: CLLocationDistance) {
        let circle = MKCircle(center: coordinate,
                              radius: radius)
        mapView.addOverlay(circle)
    }
}

extension Map: MKMapViewDelegate {
    func mapView(_ mapView: MKMapView,
                 rendererFor overlay: MKOverlay) -> MKOverlayRenderer {
        // If you want to include other shapes, then this check is needed.
        // If you only want circles, then remove it.
        if let circleOverlay = overlay as? MKCircle {
            let circleRenderer = MKCircleRenderer(overlay: circleOverlay)
            circleRenderer.fillColor = .black
            circleRenderer.alpha = 0.1

            return circleRenderer
        }

        // If other shapes are required, handle them here
        return <#Another overlay type#>
    }
}

Answer 2

我使用以下方法实现了以下目标

import UIKit
import MapKit


class MapVC: UIViewController,CLLocationManagerDelegate {
var locationManager = CLLocationManager()
@IBOutlet weak var mapView : MKMapView!
override func viewDidLoad() {
    super.viewDidLoad()


    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 = MKCoordinateRegion(center: userLocation, latitudinalMeters: 200, longitudinalMeters: 200)
        let region = CLCircularRegion(center: userLocation, radius: 5000, identifier: "geofence")
        mapView.addOverlay(MKCircle(center: userLocation, radius: 200))
        mapView.setRegion(viewRegion, animated: false)
    }

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

}

}

extension MapVC : MKMapViewDelegate{
func mapView(_ mapView: MKMapView, rendererFor overlay: MKOverlay) -> MKOverlayRenderer {

    var circleRenderer = MKCircleRenderer()
    if let overlay = overlay as? MKCircle {
        circleRenderer = MKCircleRenderer(circle: overlay)
        circleRenderer.fillColor = UIColor.green
        circleRenderer.strokeColor = .black
        circleRenderer.alpha = 0.5

    }
    return circleRenderer
}
}

我的输出：