swift - 从 @Binding var 修改 @State var 不会刷新 SwiftUI 中的 View

Question

所以我有一个包含 FilterBar 和 List 的 ParentView。它看起来像这样:

struct ParentView: View {
    @State var listCellModels: [ListCellModel]

    // Both these vars are passed to the FilterBar and adjusted by the FilterBar
    @State var isEditing: Bool = false
    @State var selectedType: FilterType = .none

    // When selected type is changed, I need to reload the models in the list with the new filter
    private var filteredModels: [ListCellModel] {
        return listCellModels.filter{
            (selectedType.rawValue == 0 || $0.approved.rawValue == selectedType.rawValue)
        }
    }

    var body: some View {
        VStack {
            FilterBar(isEditing: $isEditing, selectedType: $selectedType)

            // All the items in the list are buttons that display a custom view I had
            // this works fine, and when isEditing is changed the view DOES update
            List(filteredModels) { model in
                Button(action: {
                    // Does a thing
                }, label: {
                    ListViewCell(model: model, isEditing: self.$isEditing)
                })
            }
        }
    }
}

我的过滤器栏只是一个简单的 HStack，带有几个修改变量的按钮

struct FilterBar: View {
    @Binding var isEditing: Bool
    @Binding var selectedType: FilterType

    var body: some View {
        HStack(alignment: .center) {
            Button(action: {
                self.selectedType = FilterType.init(rawValue: (self.selectedType.rawValue + 1) % 4)!
            }, label: {
                Text("Filter: \(selectedType.name)")
            }).padding(.top).padding(.leading)

            Spacer()

            Button(action: {
                self.isEditing = !self.isEditing
            }, label: {
                Text(!isEditing ? "Edit" : "Done")
            }).padding(.top).padding(.trailing)
        }
    }
}

当我点击更改 isEditing 的按钮时，列表中的所有单元格都会更新以显示它们的“编辑”状态，但是当我点击按钮更改 selectedType 时，父 View 中的变量确实会更新，正如我所观察到的在调试器中 - 但是 View 不会重新加载。所以看起来好像仍然在应用旧的过滤器。

是否有任何原因更新此 @State var 不会重新加载 View ？

有什么解决方法吗？

Answer 1

嗯，这就像......解决方法......但是为了测试，尝试

FilterBar(isEditing: $isEditing, selectedType: $selectedType)
if selectedType != .none {
   EmptyView()
}

一般来说，将 View 模型引入为 ObservableObject 是正确的。并有 filteredModels在它作为 @Published ，所以您的 FilterBar更改了该属性，这将自动刷新 ParentView .