绑定变量的 SwiftUI 动态数组崩溃

时间:2021-05-15 11:56:00

标签: data-binding swiftui swiftui-list

我正在尝试使用 @Binding var items: [String] 在数组中动态添加/删除可编辑字符串。添加和编辑工作正常。使用 .onDelete() 调用 fatal error: Index out of range 会崩溃。我怀疑这是与视图生命周期相关的竞争条件,但我不知道如何防止这种情况(其他 StackOverflow 答案也无济于事)。

感谢您的帮助!

为了您的方便,此文件在预览中运行。

import SwiftUI

struct EditableList: View {
    @Binding var items: [String]

    var body: some View {
        Form {
            ForEach(items.indices, id: \.self) { index in
                TextEditor(text: $items[index])
            }
            .onDelete(perform: removeRows)
            Button(action: {
                items.append("")
                print(items.enumerated(), items.indices)
            }) {
                Text("Add")
            }.disabled(isAddButtonDisabled)
        }
        .navigationTitle("Items")
        .navigationBarItems(trailing: EditButton())
    }
    
    private var isAddButtonDisabled: Bool {
        var shouldDisable = false
        if let lastItem = items.last {
            shouldDisable = shouldDisable || lastItem.isEmpty
        }
        return shouldDisable
    }
    
    private func removeRows(at offsets: IndexSet) {
        items.remove(atOffsets: offsets)
    }
}

struct CreateInstructions_Previews: PreviewProvider {
    struct PreviewWrapper: View {
        @State var myItems: [String] = ["First", "Second", ""]

        var body: some View {
            EditableList(items: $myItems)
        }
    }
    
    static var previews: some View {
        Group {
            NavigationView {
                PreviewWrapper()
            }
            NavigationView {
                PreviewWrapper()
            }
            .preferredColorScheme(.dark)
        }
    }
}

0 个答案:

没有答案