相关疑难解决方法(0)

在Swift 1.2中我有这个:

class UVC: NSViewController, MKMapViewDelegate {
    // ...

    // **************************************
    // MARK: MapView Delegate
    // **************************************
    func mapView(mapView: MKMapView, rendererForOverlay overlay: MKOverlay) -> MKOverlayRenderer! {
        if overlay is OSGBTiles {
            return OSGBTilesRenderer(tileOverlay: overlay as! OSGBTiles)
        } else if overlay is ESRI {
            return ESRIRenderer(shapeFileOverlay: overlay as! ESRI)
        } else if overlay is MKTileOverlay {
            return MKTileOverlayRenderer(overlay: overlay)
        } else {
            print("Unknown overlay")
        }
        return nil
    }
}

Swift 2已经将定义更改 mapView:rendererForOverlay为现在返回MKOverlayRenderer而不是MKOverlayRenderer!,并且现在不允许我返回nil(不出所料),因为MKOverlayRenderer不是 …

这是我绘制第一条线的代码，对于另一条具有另一种颜色的线我该怎么办？

 func mapView(mapView : MKMapView! , rendererForOverlay overlay: MKOverlay!) ->MKOverlayRenderer! {

    if overlay is MKPolyline {

        var polyLineRenderer = MKPolylineRenderer(overlay: overlay)
        polyLineRenderer.strokeColor = UIColor.blackColor()
        polyLineRenderer.lineWidth = 10

        return polyLineRenderer
    }
    return nil
  }