有没有办法在mapbox视图上显示标签的thousends时提高性能？

Question

只是看起来像这样：

显示超过2k个标签。当我加载该控制器时，完成显示需要10秒以上。为什么？ 如何加快速度？

这就是我在地图集上显示它们的方法：

private func setupMapBox() {

    let url = URL(string: "mapbox://styles/kunass2/cjcubgbvq1uuq2smt3nup7nzf")
    mapView = MGLMapView(frame: .zero, styleURL: url)
    mapView.delegate = self
    mapContainerView.addSubview(mapView)

    mapView.snp.makeConstraints { make in
        make.edges.equalToSuperview()
    }
}

private func setupFetchedResultsController() {

    let context = NSManagedObjectContext.mr_default()
    let fetchRequest = NSFetchRequest<Label>(entityName: "Label")
    let nameDescriptor = NSSortDescriptor(key: "text", ascending: true, selector: #selector(NSString.caseInsensitiveCompare(_:)))

    fetchRequest.predicate = NSPredicate(format: "territory.identifier = %@", territory.identifier)
    fetchRequest.sortDescriptors = [nameDescriptor]

    fetchedResultsController = NSFetchedResultsController(fetchRequest: fetchRequest, managedObjectContext: context, sectionNameKeyPath: nil, cacheName: nil)
    fetchedResultsController.delegate = self
    try! fetchedResultsController.performFetch()
    reloadAnnotations()
}

private func reloadAnnotations() {
    mapView.removeAnnotations(mapView.annotations ?? [])
    mapView.addAnnotations(fetchedResultsController.fetchedObjects!)
}

以下是我的代表：

//MARK: - NSFetchedResultsControllerDelegate

func controller(_ controller: NSFetchedResultsController<NSFetchRequestResult>, didChange anObject: Any, at indexPath: IndexPath?, for type: NSFetchedResultsChangeType, newIndexPath: IndexPath?) {

    if let label = anObject as? Label {
        switch type {
        case .insert:
            mapView.addAnnotation(label)
        case .delete:
            mapView.removeAnnotation(label)
        case .update:
            fallthrough
        case .move:
            mapView.removeAnnotation(label)
            mapView.addAnnotation(label)
        }
    }
}

//MARK: - MGLMapViewDelegate

func mapView(_ mapView: MGLMapView, didFinishLoading style: MGLStyle) {
    setupFetchedResultsController()
}

func mapView(_ mapView: MGLMapView, viewFor annotation: MGLAnnotation) -> MGLAnnotationView? {

    guard let label = annotation as? Label else {
        return nil
    }
    return LabelAnnotationView(label: label)
}

在viewDidLoad中的

我只是致电：

setupMapBox()

Answer 1

MGLSymbolStyleLayer应该更高效。 This example包含使用文本的符号图层。因为符号图层直接在GL中渲染，所以它们更轻量级。

注释使用本机UIViews，因此在使用多个时效果较差。有关向地图添加点的不同方法的优缺点的详细信息，请参阅this guide。