尝试将MKTileOverlay对象添加到MKMapView时出现错误"Expected a MKTileOverlay但got (null)“

Question

添加了MKMapView类并为其分配了委托：

let mapView: MKMapView = {

    let map = MKMapView()
    map.translatesAutoresizingMaskIntoConstraints = false
    return map
}()

override func viewDidLoad() {

self.view.addSubview(mapView)

    mapView.delegate = self

let center = mapView.centerCoordinate

    NSLayoutConstraint.activate([
        mapView.topAnchor.constraint(equalTo: self.view.safeAreaLayoutGuide.topAnchor, constant: 0),
        mapView.leftAnchor.constraint(equalTo: self.view.safeAreaLayoutGuide.leftAnchor, constant: 0),
        mapView.rightAnchor.constraint(equalTo: self.view.safeAreaLayoutGuide.rightAnchor, constant: 0),
        mapView.bottomAnchor.constraint(equalTo: self.view.safeAreaLayoutGuide.bottomAnchor, constant: 0)
    ])
}

然后为mapView分配center坐标，并设置跨度。zoomLevel设置为1

let span = MKCoordinateSpan(latitudeDelta: 0, longitudeDelta: 360 / pow(2, Double(zoomLevel)) * Double(mapView.frame.size.width) / 256)
        setRegion(MKCoordinateRegion(center: coordinate, span: span), animated: animated)

//我之所以这样写URL，是因为有人告诉我，MKTileOverlay类将处理z、x和y值。

let urlTemplate = "https://tile.openweathermap.org/map/temp_new/{z}/{x}/{y}.png?appid={my API ID}"

//在MKTileOverlay中添加urlTemplate

            let overlay = MKTileOverlay(urlTemplate: urlTemplate)

            overlay.canReplaceMapContent = true

//就在我要向mapView添加overlay的时候，应用程序崩溃了：

self.mapView.addOverlay(overlay)

//它将我带到AppDelegate.swift，然后显示以下消息：

Thread 1: Exception: "Expected a MKTileOverlay but got (null)"

所有内容都添加到了viewDidLoad()中。

我还添加了renderedFor委托函数。如下所示：

func mapView(_ mapView: MKMapView, rendererFor overlay: MKOverlay) -> MKOverlayRenderer {

    var renderer = MKTileOverlayRenderer()

    print("overlay rendered For: \(overlay)")

    if overlay is MKTileOverlay {
        renderer = MKTileOverlayRenderer(overlay:overlay)
        renderer.alpha = 0.8
    }

    return renderer
}

Answer 1

我也有同样的问题，导致我崩溃的原因是没有指定覆盖的MKTileOverlayRenderer()的初始化。

所以基本上，你在mapView(_:rendererFor:)委托方法中的代码应该是：

func mapView(_ mapView: MKMapView, rendererFor overlay: MKOverlay) -> MKOverlayRenderer {

    print("overlay rendered For: \(overlay)")

    if let overlay = overlay as? MKTileOverlay {
        renderer = MKTileOverlayRenderer(overlay: overlay)
        renderer.alpha = 0.8
        return renderer.alpha
    } else {
        return MKOverlayRenderer(overlay: overlay)
    }

}