如何使用MapKit和Swift绘制多边形覆盖层

Question

我正在尝试在地图上绘制一个多边形，但是出现了问题，代码似乎无法工作。我在这里做错了什么？

import UIKit
import MapKit

class ViewController: UIViewController {

    @IBOutlet weak var mapView: MKMapView!
    override func viewDidLoad() {
        super.viewDidLoad()
        let initialLocation = CLLocation(latitude: 49.140838, longitude: -123.127886)
        centerMapOnLocation(initialLocation)
        addBoundry()
    }


    func addBoundry()
    {
        var points=[CLLocationCoordinate2DMake(49.142677,  -123.135139),CLLocationCoordinate2DMake(49.142730, -123.125794),CLLocationCoordinate2DMake(49.140874, -123.125805),CLLocationCoordinate2DMake(49.140885, -123.135214)]

        let polygon = MKPolygon(coordinates: &points, count: points.count)

        mapView.addOverlay(polygon)
    }


    let regionRadius: CLLocationDistance = 1000
    func centerMapOnLocation(location: CLLocation) {
        let coordinateRegion = MKCoordinateRegionMakeWithDistance(location.coordinate,
            regionRadius * 2.0, regionRadius * 2.0)
        mapView.setRegion(coordinateRegion, animated: true)
    }


}


func mapView(mapView: MKMapView!, rendererForOverlay overlay: MKOverlay!) -> MKOverlayRenderer! {
        if overlay is MKPolygon {
        let polygonView = MKPolygonRenderer(overlay: overlay)
        polygonView.strokeColor = UIColor.magentaColor()

        return polygonView
    }

    return nil
}

- Sicong Liu

Answer 1

您似乎已经实现了mapView(_:renderFor:)（以前称为rendererForOverlay）作为全局函数。该方法必须在ViewController类定义内部，或者更好的方法是将其放在MKMapViewDelegate扩展内部，以保持我们的代码整洁有序：

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

此外，请确保您已将视图控制器定义为地图视图的delegate。最简单的方法可能是在IB中执行此操作，但您也可以在viewDidLoad中执行：

mapView.delegate = self

- Rob