iOS 8 SDK，Swift，MapKit绘制路线 [英] iOS 8 SDK, Swift, MapKit Drawing a Route

问题描述

我需要在两点之间绘制路线，并且出于目的使用MKDirectionsRequest.

I need to draw route between two points and I'm using MKDirectionsRequest for my purpose.

获取路线是可以的，但是我在绘制它时遇到了麻烦.

Getting a route is OK, but I have trouble with drawing it.

在iOS 8 SDK中没有功能

In iOS 8 SDK there's no function

- (MKOverlayView *)mapView:(MKMapView *)mapView viewForOverlay:(id <MKOverlay>)overlay 

只有一个:

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

由于某种原因，我不明白为什么未调用该方法.
设置了MapView的代理，并导入了MapKit.

And for some reason, I can't understand why that method isn't called.
Delegate for MapView is set and MapKit is imported.

这是实现的rendererForOverlay函数:

Here is the rendererForOverlay function that is implemented:

func rendererForOverlay(overlay: MKOverlay!) -> MKOverlayRenderer! {
    println("rendererForOverlay");

    var overlayRenderer : MKOverlayRenderer = MKOverlayRenderer(overlay: overlay);

    var overlayView : MKPolylineRenderer = MKPolylineRenderer(overlay: overlay);
    view.backgroundColor = UIColor.blueColor().colorWithAlphaComponent(0.5);

    return overlayView;
}

推荐答案

地图视图未调用您的rendererForOverlay方法，因为其名称不正确.

The map view isn't calling your rendererForOverlay method because it is not named correctly.

该方法必须准确命名:

mapView(mapView:rendererForOverlay)

但是在您的代码中它被命名为:

but in your code it's named:

rendererForOverlay(overlay:)

另外，您应该检查overlay参数的类型是否为MKPolyline并设置折线渲染器的strokeColor.

In addition, you should check that the type of the overlay argument is MKPolyline and set the strokeColor of the polyline renderer.

(现有代码中的view.backgroundColor实际上正在更改视图控制器view的背景颜色-而不是折线.)

(The view.backgroundColor in the existing code is actually changing the background color of the view controller's view -- not the polyline.)

示例:

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

    if (overlay is MKPolyline) {
        var pr = MKPolylineRenderer(overlay: overlay);
        pr.strokeColor = UIColor.blueColor().colorWithAlphaComponent(0.5);
        pr.lineWidth = 5;
        return pr;
    }

    return nil
}

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