Swift MKMapView 多边形叠加故障

使用Swift中的MKMapView时，如果我们想要在地图上叠加一个多边形，可能会遇到一些故障。今天我们将探讨这个问题，并提供解决方案。

import MapKit
class ViewController: UIViewController {
    @IBOutlet weak var mapView: MKMapView!
    override func viewDidLoad() {
        super.viewDidLoad()
        // 创建多边形坐标点
        let points = [
            CLLocationCoordinate2D(latitude: 37.785834, longitude: -122.406417),
            CLLocationCoordinate2D(latitude: 37.758056, longitude: -122.428611),
            CLLocationCoordinate2D(latitude: 37.775, longitude: -122.418333)
        ]
        // 将点转换为地图坐标系
        let mapPoints = points.map { self.mapView.convert($0, toCoordinateFrom: self.mapView) }
        // 创建多边形
        let polygon = MKPolygon(coordinates: mapPoints, count: mapPoints.count)
        // 将多边形添加到地图视图中
        self.mapView.addOverlay(polygon)
    }
}
extension ViewController: MKMapViewDelegate {
    func mapView(_ mapView: MKMapView, rendererFor overlay: MKOverlay) -> MKOverlayRenderer {
        if let polygon = overlay as? MKPolygon {
            let renderer = MKPolygonRenderer(polygon: polygon)
            renderer.fillColor = UIColor.red.withAlphaComponent(0.5)
            return renderer
        }
        return MKOverlayRenderer()
    }
}