swift - MapBox IOS SDK swift : how to show the user annotations from specific zoomLevel without delete and add again?

Question

正如您在这里看到的，每次缩放级别发生变化时，我都会删除和添加注释，但问题是速度太慢并且应用程序卡住了。我搜索了所有 MapBox 文档，但没有找到实现它的更好方法。

isFull 、 isMedium 和 isEmpty 只是我需要的缩放级别的标志。

感谢帮助者:)

内部函数 mapView(mapView: MGLMapView, regionDidChangeAnimated animated: Bool) { 如果 (mapView.zoomLevel > 14) {

        isFull = true
        isMedium = false
        isEmpty = false
        if (gotMyHistory)
        {
            if (mapView.annotations?.count > 0){mapView.removeAnnotations(mapView.annotations!)}
        LoadAnnotation()
        }
    }else if (mapView.zoomLevel <= 14 && mapView.zoomLevel >= 8 && !isMedium )
    {

        isFull = false
        isMedium = true
        isEmpty = false
        if (gotMyHistory )
        {
            if (mapView.annotations?.count > 0){mapView.removeAnnotations(mapView.annotations!)}
            LoadAnnotation()
        }
    }else if (mapView.zoomLevel < 8 && !isEmpty)
    {
        isFull = false
        isMedium = false
        isEmpty = true
        if (gotMyHistory)
        {
            if (mapView.annotations?.count > 0){mapView.removeAnnotations(mapView.annotations!)}
        }
    }

Answer 1

我意识到这可能与原始发帖人无关，因为已经过去了很多时间，但希望对其他人有所帮助。 我遇到了同样的问题，经过 3 种不同的实现(首先是像您一样使用注释)，我发现创建自己的 map 层是最流畅的选择。

  // Wait until the style is loaded before modifying the map style
func mapView(_ mapView: MGLMapView, didFinishLoading style: MGLStyle) {

    //Bicycle Parking Annotations Layer
    let bicycleParkingSource = MGLShapeSource(identifier: "bicycleParking", features: [], options: nil)
    self.bicycleParkingSource = bicycleParkingSource

    style.setImage(UIImage(named: "bicycleParking")!, forName: "bicycleParking") // referenced by an MGLSymbolStyleLayer’s iconImage

    let bicycleParkingSymbols = MGLSymbolStyleLayer(identifier: "bicycleParking", source: bicycleParkingSource)
    bicycleParkingSymbols.iconImageName = MGLStyleValue(rawValue: "bicycleParking")
    bicycleParkingSymbols.minimumZoomLevel = 12.0

    style.addSource(bicycleParkingSource)
    style.addLayer(bicycleParkingSymbols)
}

我实际上发现 Mapbox 在完成后有一个很好的教程，它有助于改进我的代码。 https://www.mapbox.com/ios-sdk/examples/runtime-multiple-annotations/ 如您所见，您可以为图层设置最大可见缩放级别。希望这可以帮助!