iOS 14上的SwiftUI / UIKit自省

如何解决iOS 14上的SwiftUI / UIKit自省

我有一个使用UIViewRepresentable并查看自省以在SwiftUI应用程序中为ScrollView创建提拉刷新功能的应用程序，该应用程序可在iOS 13中使用。但是，iOS 14破坏了它，并且我不知道该如何解决。这是实现：

import SwiftUI
import Introspect

private struct PullToRefresh: UIViewRepresentable {
    
    @Binding var isShowing: Bool
    let onRefresh: () -> Void
    
    public init(
        isShowing: Binding<Bool>,onRefresh: @escaping () -> Void
    ) {
        _isShowing = isShowing
        self.onRefresh = onRefresh
    }
    
    public class Coordinator {
        let onRefresh: () -> Void
        let isShowing: Binding<Bool>
        
        init(
            onRefresh: @escaping () -> Void,isShowing: Binding<Bool>
        ) {
            self.onRefresh = onRefresh
            self.isShowing = isShowing
        }
        
        @objc
        func onValueChanged() {
            isShowing.wrappedValue = true
            onRefresh()
        }
    }
    
    public func makeUIView(context: UIViewRepresentableContext<PullToRefresh>) -> UIView {
        let view = UIView(frame: .zero)
        view.isHidden = true
        view.isUserInteractionEnabled = false
        return view
    }
    
    private func tableView(entry: UIView) -> UIScrollView? {
        
        // Search in ancestors - FAILS HERE
        if let tableView = Introspect.findAncestor(ofType: UIScrollView.self,from: entry) {
            return tableView
        }

        guard let viewHost = Introspect.findViewHost(from: entry) else {
            return nil
        }

        // Search in siblings - FAILS HERE
        return Introspect.previousSibling(containing: UIScrollView.self,from: viewHost)
    }

    public func updateUIView(_ uiView: UIView,context: UIViewRepresentableContext<PullToRefresh>) {
        
        DispatchQueue.main.asyncAfter(deadline: .now()) {
            
            guard let tableView = self.tableView(entry: uiView) else {
                return
            }
            
            if let refreshControl = tableView.refreshControl {
                if self.isShowing {
                    refreshControl.beginRefreshing()
                } else {
                    refreshControl.endRefreshing()
                }
                return
            }
            
            let refreshControl = UIRefreshControl()
            refreshControl.addTarget(context.coordinator,action: #selector(Coordinator.onValueChanged),for: .valueChanged)
            tableView.refreshControl = refreshControl
        }
    }
    
    public func makeCoordinator() -> Coordinator {
        return Coordinator(onRefresh: onRefresh,isShowing: $isShowing)
    }
}

extension View {
    public func pullToRefresh(isShowing: Binding<Bool>,onRefresh: @escaping () -> Void) -> some View {
        return overlay(
            PullToRefresh(isShowing: isShowing,onRefresh: onRefresh)
                .frame(width: 0,height: 0),alignment: .center)
    }
}

此代码与this repository略有修改。

这是用法的粗略版本：

NavigationView {
            VStack(alignment: .center) {
                ...
                GeometryReader { geometry in
                    ScrollView(.vertical) {
                        ...
                    }
                    .pullToRefresh(isShowing: self.$refreshingEvents,onRefresh: refreshEvents)
                }
            }.navigationBarTitle("Events",displayMode: .inline)
        }

使用此功能时，ScrollView没有附加刷新指示器。将pullToRefresh移动到ScrollView的子视图不会改变任何内容。这是自省的结果：

PlatformViewHost<PlatformViewRepresentableAdaptor<PullToRefresh>>
_UIHostingView<ModifiedContent<Element,StyleContextWriter<SidebarStyleContext>>>
UIViewControllerWrapperView
UINavigationTransitionView
UILayoutContainerView
_UIPanelControllerContentView
_UISplitViewControllerPanelImplView
PlatformViewHost<PlatformViewControllerRepresentableAdaptor<MulticolumnSplitViewRepresentable<Element,Never,_UnaryViewAdaptor<EmptyView>>>>
_UIHostingView<_ViewList_View>
UIViewControllerWrapperView
UITransitionView
UILayoutContainerView
PlatformViewHost<PlatformViewControllerRepresentableAdaptor<UIKitTabView>>
_UIHostingView<ModifiedContent<MainView,_EnvironmentKeyWritingModifier<Optional<UserData>>>>
UIDropShadowView
UITransitionView
UIWindow

那里应该有一个UIScrollView，但是在iOS 14上没有。{p1}有没有办法我可以修复当前代码或使用保留相同功能的替代方法对其进行更新？ >