相关疑难解决方法(0)

可以帮我制作MKPolyline带有附加参数颜色的自定义吗？

CustomPolyline.swift

import Foundation
import MapKit
class CustomPolyline : MKPolyline {
    let coordinates: UnsafeMutablePointer<CLLocationCoordinate2D>
    let count : Int = 0
    let color : String = "ff0000"
    init(coordinates: UnsafeMutablePointer<CLLocationCoordinate2D>, count: Int, color: String) {

        self.coordinates = coordinates
        self.count = count
        self.color = color
    }
}

在里面

Polyline = CustomPolyline(coordinates: &Path, count: Path.count, color: "ff0000")
self.mapView.addOverlay(Polyline)

func mapView(mapView: MKMapView!, rendererForOverlay overlay: MKOverlay!) -> MKOverlayRenderer! {      
        if (overlay is CustomPolyline) {
            var pr = MKPolylineRenderer(overlay: overlay);
            pr.strokeColor = UIColor.colorWithRGBHex(0xff0000).colorWithAlphaComponent(0.5);
            pr.lineWidth = …

我收到了这个错误

"Nil与返回类型'MKOverlayRenderer'不兼容".

这是我的代码:

func mapView(mapView: MKMapView, rendererForOverlay overlay: MKOverlay) -> MKOverlayRenderer {
    if overlay is MKCircle {
      let circleRenderer = MKCircleRenderer(overlay: overlay)
      circleRenderer.lineWidth = 1.0
      circleRenderer.strokeColor = UIColor.purpleColor()
      circleRenderer.fillColor = UIColor.purpleColor().colorWithAlphaComponent(0.4)
      return circleRenderer
    }
      return nil
  }

它为什么会发生？