SwiftUI 列表在任何视图更改时重置滚动

如何解决SwiftUI 列表在任何视图更改时重置滚动

I have a very simple List with some Sections,in the same view I have also one button which will become enabled when any of list items are selected,this is controlled with a State variable,when this is happening,if list is向下滚动，状态变量将更改（以启用按钮）并且所有视图都将刷新，导致我的列表滚动到顶部。如何避免这种滚动重置，我应该提到如果元素被删除或添加到列表中也会发生同样的情况，但是，我试图尽可能地简化问题，这是简化的代码片段。

import SwiftUI

enum FavoritesListActiveSheet: Identifiable {
    case moveToSheet
    
    var id: Int { hashValue }
}

struct Category: Identifiable {
    var id: UUID = UUID()
    var name: String
}

extension Category {
    static var categories: [Category] {
        [
            Category(name: "category 1"),Category(name: "category 2")
        ]
    }
}

struct FavoriteItem: Identifiable {
    var id: UUID = UUID()
    var name: String
    var category: String
    var selected: Bool
}

extension FavoriteItem {
    static var favoriteItems: [FavoriteItem] {
        [
            FavoriteItem(name: "Item 1",category: "category 1",selected: false),FavoriteItem(name: "Item 2",FavoriteItem(name: "Item 3",FavoriteItem(name: "Item 4",category: "category 2",FavoriteItem(name: "Item 5",FavoriteItem(name: "Item 6",FavoriteItem(name: "Item 7",FavoriteItem(name: "Item 8",FavoriteItem(name: "Item 9",FavoriteItem(name: "Item 10",FavoriteItem(name: "Item 11",FavoriteItem(name: "Item 12",FavoriteItem(name: "Item 13",FavoriteItem(name: "Item 14",FavoriteItem(name: "Item 15",FavoriteItem(name: "Item 16",FavoriteItem(name: "Item 17",FavoriteItem(name: "Item 18",]
    }
}

struct FavoritesRaw: View {

    @Binding var item: FavoriteItem
    @State var refreshView: Bool = false

    let onItemToggle: () -> ()

    var body: some View {
        HStack {
            if (item.selected) {
                Image(systemName: "checkmark.circle")
            } else {
                Image(systemName: "circle")
            }

            Text (item.name)
        }
        .simultaneousGesture(TapGesture().onEnded {

            self.item.selected.toggle()

            refreshView.toggle()
            onItemToggle()
        })
        .contentShape(Rectangle())
    }
}

class FavoritesViewModel: ObservableObject {
    var favorite_items: [FavoriteItem] = FavoriteItem.favoriteItems
}

struct FavoritesListView: View {
    @StateObject var viewModel: FavoritesViewModel = FavoritesViewModel()

    @State var addtoButtonDisabled: Bool = true
    @State var sheetDisplayed: FavoritesListActiveSheet?

    var body: some View {
        NavigationView {
            VStack {
                List {
                    ForEach (Category.categories) { category in
                        Section (header: Text(category.name))
                        {
                            ForEach (self.viewModel.favorite_items.filter({$0.category == category.name})) { item in
                                FavoritesRaw(item: binding(for: item),onItemToggle: {
                                    addtoButtonDisabled = (self.viewModel.favorite_items.filter({$0.selected == true}).count == 0)
                                })
                            }
                        }
                        .textCase(nil)
                        
                    }
                }
                .listStyle(PlainListStyle())
                .id(UUID()) // no animation
            }
            .navigationBarTitle("Favorites",displayMode: .inline)
            .toolbar {
                ToolbarItemGroup(placement: .navigationBarTrailing) {

                    Button(action: {
                        sheetDisplayed = .moveToSheet
                    }) {
                        Text("Add to...")
                    }.disabled(addtoButtonDisabled)
                }
            }
            .sheet(item: $sheetDisplayed) { item in
                // [Show a sheet then disable back the button]
            }
        }
        .onAppear
        {
            addtoButtonDisabled = (self.viewModel.favorite_items.filter({$0.selected == true}).count == 0)
        }
    }

    private func binding(for item: FavoriteItem) -> Binding<FavoriteItem> {
        guard let item_index = self.viewModel.favorite_items.firstIndex(where: { $0.id == item.id }) else {
             fatalError("Can't find item in array")
         }
        return $viewModel.favorite_items[item_index]
     }
}

解决方法

好像删除

.id(UUID()) // 没有动画

正在解决我的问题。但是，我添加了这个以摆脱丑陋的动画，SwiftUI 提供了元素删除功能。