MKPolygon初始化错误“在调用中参数'interiorPolygons'缺少参数” /“呼叫中的额外参数” [英] MKPolygon initialization error "Missing argument for parameter 'interiorPolygons' in call" / "Extra argument in call"

问题描述

我正在尝试转换 MKPolygon 引用中的Objective-C代码预发行/ ios /文档/ UserExperience / Conceptual / LocationAwarenessPG / AnnotatingMaps / AnnotatingMaps.html＃// apple_ref / doc / uid / TP40009497-CH6-SW1rel =nofollow>清单6-9 进入Swift。

I'm trying to convert the Objective-C code in the MapKit MKPolygon reference in Listing 6-9 into Swift.

当我使用

 init(coordinates:count:)

初始化函数，我收到错误：

init function, I get the error:

在调用中缺少参数'interiorPolygons'的参数

Missing argument for parameter 'interiorPolygons' in call

当我调用函数时interiorPolygons参数，我收到错误：

When I call the function with the interiorPolygons argument, I get the error:

调用中的额外参数

Extra argument in call

这是我正在使用的代码。

Here is the code that I am using.

 var points: [CLLocationCoordinate2D] = [CLLocationCoordinate2D]()

 points[0] = CLLocationCoordinate2DMake(41.000512, -109.050116)
 points[1] = CLLocationCoordinate2DMake(41.002371, -102.052066)
 points[2] = CLLocationCoordinate2DMake(36.993076, -102.041981)
 points[3] = CLLocationCoordinate2DMake(36.99892, -109.045267)

 var poly: MKPolygon = MKPolygon(points, 4)

 poly.title = "Colorado"
 theMapView.addOverlay(poly)

更新：

 points.withUnsafePointerToElements() { (cArray: UnsafePointer<CLLocationCoordinate2D>) -> () in
            poly = MKPolygon(coordinates: cArray, count: 4)
        }

似乎摆脱了编译器错误，但仍然没有添加叠加层。

seems to get rid of the compiler error, but still doesn't add an overlay.

推荐答案

以下问题：

var poly: MKPolygon = MKPolygon(points, 4)

它不给初始化程序的参数标签，并且它没有将 points 作为指针传递。

are that it doesn't give the argument labels for the initializer and it's not passing points as a pointer.

将行更改为：

var poly: MKPolygon = MKPolygon(coordinates: &points, count: 4)

（更新中的 points.withUnsafePointerToElements ... 版本也会有效。）

另请注意 var points：[CLLocationCoordinate2D] = [CLLocationCoordinate2D]（）创建一个空数组。执行 points [0] = ... 应该会导致运行时错误，因为数组没有元素可以开始。而是使用 points.append（）将坐标添加到数组中：

Also note that var points: [CLLocationCoordinate2D] = [CLLocationCoordinate2D]() creates an empty array. Doing points[0] = ... should cause a run-time error since the array has no elements to begin with. Instead, add the coordinates to the array using points.append():

points.append(CLLocationCoordinate2DMake(41.000512, -109.050116))
points.append(CLLocationCoordinate2DMake(41.002371, -102.052066))
points.append(CLLocationCoordinate2DMake(36.993076, -102.041981))
points.append(CLLocationCoordinate2DMake(36.99892, -109.045267))

或者只是一起声明和初始化：

or just declare and initialize together:

var points = [CLLocationCoordinate2DMake(41.000512, -109.050116),
              CLLocationCoordinate2DMake(41.002371, -102.052066),
              CLLocationCoordinate2DMake(36.993076, -102.041981),
              CLLocationCoordinate2DMake(36.99892, -109.045267)]

< br>
如果仍然没有看到叠加层，请确保已实现 rendererForOverlay 委托方法（并设置或连接地图视图的委托 property）：

If you still don't see the overlay, make sure you've implemented the rendererForOverlay delegate method (and set or connected the map view's delegate property):

func mapView(mapView: MKMapView!, rendererForOverlay overlay: MKOverlay!) -> MKOverlayRenderer! {
    if overlay is MKPolygon {
        var polygonRenderer = MKPolygonRenderer(overlay: overlay)
        polygonRenderer.fillColor = UIColor.cyanColor().colorWithAlphaComponent(0.2)
        polygonRenderer.strokeColor = UIColor.blueColor().colorWithAlphaComponent(0.7)
        polygonRenderer.lineWidth = 3
        return polygonRenderer
    }

    return nil
}

不相关：而不是调用数组 points ， coordinates 可能更好，因为 points 意味着数组可能包含 MKMapPoint 结构，这是（points：count：）初始值设定项作为第一个参数。

Unrelated: Rather than calling the array points, coordinates might be better because points implies the array might contain MKMapPoint structs which is what the (points:count:) initializer takes as the first argument.

这篇关于MKPolygon初始化错误“在调用中参数'interiorPolygons'缺少参数” /“呼叫中的额外参数”的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！