SwiftUI：随机 "Extra argument in call" 错误

Question

所以我正在尝试学习 SwiftUI 和 Combine。我通常通过制作一个简单的小费计算器来开始新技术。

我似乎在编码时遇到随机 "Extra argument in call." 错误这是我的 SwiftUI 文件

import SwiftUI

internal enum ReceiptRowType {
    case subtotal
    case tax
    case total
    case tip
    case grandTotal
}

struct TipView: View {
    @ObservedObject internal var adBannerView: BannerAdView = BannerAdView()
    @ObservedObject internal var receiptViewModel: ReceiptViewModel

    private let percentageFormatter: NumberFormatter = {
        let f = NumberFormatter()
        f.numberStyle = .percent
        return f
    }()

    var body: some View {
        ZStack {
            Color.white
                .scaledToFit()

            VStack {
                if adBannerView.adHasLoaded {
                    adBannerView
                        .frame(maxHeight: adBannerView.adHeight)
                        .animation(.easeInOut(duration: 2.0))
                }

                BorderView()

                Text(ARCHLocalizedStrings.receipt)
                    .foregroundColor(Color.gray)

                BorderView()

                HStack {
                    Spacer()

                    Button(action: {
                        self.receiptViewModel.addNewReceiptItem()
                    }) {
                        Text(ARCHLocalizedStrings.buttonTitleAddItem)
                    }
                }

                BorderView()

                ScrollView {
                    ForEach(receiptViewModel.receiptItems) { receiptItem in
                        ItemView(receiptItem: receiptItem)

                        if receiptItem != self.receiptViewModel.receiptItems.last {
                            Divider()
                        }
                    }
                }

                BorderView()

                BottomOfReceiptRow(receiptViewModel: receiptViewModel,
                                   type: ReceiptRowType.subtotal,
                                   title: ARCHLocalizedStrings.subtotal)

                BottomOfReceiptRow(receiptViewModel: receiptViewModel,
                                   type: ReceiptRowType.tax,
                                   title: ARCHLocalizedStrings.tax)
            }
            .padding(.horizontal, ARCHSwiftUILayoutConstants.defaultPaddingAndSpacing)
        }
    }
}

struct BorderView: View {
    var body: some View {
        Text("================================")
            .lineLimit(1)
            .foregroundColor(Color.gray)
            .minimumScaleFactor(0.5)
    }
}

struct ItemView: View {
    @ObservedObject var receiptItem: ReceiptItemViewModel

    var body: some View {
        HStack {
            TextField(receiptItem.name, text: $receiptItem.name)
                .textFieldStyle(RoundedBorderTextFieldStyle())
                .foregroundColor(Color.gray)
                .multilineTextAlignment(TextAlignment.leading)

            TextField("Price", value: $receiptItem.price, formatter: ARCHUtilities.currencyFormatter)
                .textFieldStyle(RoundedBorderTextFieldStyle())
                .foregroundColor(Color.gray)
                .multilineTextAlignment(TextAlignment.trailing)
                .minimumScaleFactor(0.5)
                .frame(width: ARCHSwiftUILayoutConstants.widthForCurrency)
        }
    }
}

struct BottomOfReceiptRow: View {
    @ObservedObject internal var receiptViewModel: ReceiptViewModel

    internal var type: ReceiptRowType
    internal var title: String

    var body: some View {
        HStack {
            Spacer()

            Text(title)
                .foregroundColor(Color.gray)

            if type == ReceiptRowType.subtotal {
                Text("\(receiptViewModel.subtotal)")
                    .foregroundColor(Color.gray)
                    .frame(width: ARCHSwiftUILayoutConstants.widthForCurrency)
            } else if type == ReceiptRowType.tax {
                Text("\(receiptViewModel.taxRate)")
                    .foregroundColor(Color.gray)
                    .frame(width: ARCHSwiftUILayoutConstants.widthForCurrency)
            } else if type == ReceiptRowType.total {
                Text("\(receiptViewModel.total)")
                    .foregroundColor(Color.gray)
                    .frame(width: ARCHSwiftUILayoutConstants.widthForCurrency)
            } else if type == ReceiptRowType.tip {

            } else if type == ReceiptRowType.grandTotal {
                Text("\(receiptViewModel.grandTotal)")
                    .foregroundColor(Color.gray)
                    .frame(width: ARCHSwiftUILayoutConstants.widthForCurrency)
            }
        }
    }
}

struct TipView_Previews: PreviewProvider {
    static var previews: some View {
        TipView(receiptViewModel: ReceiptViewModel())
    }
}

但是，如果我在 TipView 正文（任何视图）上添加另一个视图，我似乎会收到 "Extra argument in call" 错误。

Picture of error here

有人知道这是怎么回事吗？

Answer 1

SwiftUI 中的@ViewBuilder 系统在任何给定的视图容器中限制为 10 个视图。第 11 个视图没有参数，所以你得到了那个错误。

基本解决方案：

这里的问题是您的 VStack 已达到最大容量，但是您可以将这些现有视图包装在其他容器中。作为一个非常基本的示例，您可以显示 10 BottomReceiptRow 个视图：

    var body: some View {
    ZStack {
        Color.white
            .scaledToFit()

// Modifications start here

        VStack {
            if adBannerView.adHasLoaded {
                adBannerView
                    .frame(maxHeight: adBannerView.adHeight)
                    .animation(.easeInOut(duration: 2.0))
            }

            BorderView()

            Text(ARCHLocalizedStrings.receipt)
                .foregroundColor(Color.gray)

            BorderView()

            HStack {
                Spacer()

                Button(action: {
                    self.receiptViewModel.addNewReceiptItem()
                }) {
                    Text(ARCHLocalizedStrings.buttonTitleAddItem)
                }
            }

            BorderView()

            ScrollView {
                ForEach(receiptViewModel.receiptItems) { receiptItem in
                    ItemView(receiptItem: receiptItem)

                    if receiptItem != self.receiptViewModel.receiptItems.last {
                        Divider()
                    }
                }
            }

            BorderView()

            Group {
                BottomOfReceiptRow(receiptViewModel: receiptViewModel,
                                   type: ReceiptRowType.subtotal,
                                   title: ARCHLocalizedStrings.subtotal)

                BottomOfReceiptRow(receiptViewModel: receiptViewModel,
                                   type: ReceiptRowType.tax,
                                   title: ARCHLocalizedStrings.tax)

                BottomOfReceiptRow(receiptViewModel: receiptViewModel,
                                   type: ReceiptRowType.someValue,
                                   title: ARCHLocalizedStrings.someValue)

                BottomOfReceiptRow(receiptViewModel: receiptViewModel,
                                   type: ReceiptRowType.someValue2,
                                   title: ARCHLocalizedStrings.someValue2)

                BottomOfReceiptRow(receiptViewModel: receiptViewModel,
                                   type: ReceiptRowType.someValue3,
                                   title: ARCHLocalizedStrings.someValue3)

                BottomOfReceiptRow(receiptViewModel: receiptViewModel,
                                   type: ReceiptRowType.someValue4,
                                   title: ARCHLocalizedStrings.someValue4)

                BottomOfReceiptRow(receiptViewModel: receiptViewModel,
                                   type: ReceiptRowType.someValue5,
                                   title: ARCHLocalizedStrings.someValue5)
            }
// Modifications end here

        }
        .padding(.horizontal, ARCHSwiftUILayoutConstants.defaultPaddingAndSpacing)
    }
}

或者：

您可能更愿意将这些部分完全重构为它们自己的部分 View，因为组合使代码更易于阅读。不过这里并不是绝对必要的。

如果您确实想这样做，您可以考虑一个示例，其中这些收据行都在它们自己的视图中，例如：

    var body: some View {
    ZStack {
        Color.white
            .scaledToFit()

        VStack {
            if adBannerView.adHasLoaded {
                adBannerView
                    .frame(maxHeight: adBannerView.adHeight)
                    .animation(.easeInOut(duration: 2.0))
            }

            BorderView()

            Text(ARCHLocalizedStrings.receipt)
                .foregroundColor(Color.gray)

            BorderView()

            HStack {
                Spacer()

                Button(action: {
                    self.receiptViewModel.addNewReceiptItem()
                }) {
                    Text(ARCHLocalizedStrings.buttonTitleAddItem)
                }
            }

            BorderView()

            ScrollView {
                ForEach(receiptViewModel.receiptItems) { receiptItem in
                    ItemView(receiptItem: receiptItem)

                    if receiptItem != self.receiptViewModel.receiptItems.last {
                        Divider()
                    }
                }
            }

            BorderView()

            bottomRow
        }
        .padding(.horizontal, ARCHSwiftUILayoutConstants.defaultPaddingAndSpacing)
    }
}

// Additional computed property in TipView
var bottomRow: some View {
    Group {
        BottomOfReceiptRow(receiptViewModel: receiptViewModel,
                           type: ReceiptRowType.subtotal,
                           title: ARCHLocalizedStrings.subtotal)

        BottomOfReceiptRow(receiptViewModel: receiptViewModel,
                           type: ReceiptRowType.tax,
                           title: ARCHLocalizedStrings.tax)

        BottomOfReceiptRow(receiptViewModel: receiptViewModel,
                           type: ReceiptRowType.someValue,
                           title: ARCHLocalizedStrings.someValue)

        BottomOfReceiptRow(receiptViewModel: receiptViewModel,
                           type: ReceiptRowType.someValue2,
                           title: ARCHLocalizedStrings.someValue2)

        BottomOfReceiptRow(receiptViewModel: receiptViewModel,
                           type: ReceiptRowType.someValue3,
                           title: ARCHLocalizedStrings.someValue3)

        BottomOfReceiptRow(receiptViewModel: receiptViewModel,
                           type: ReceiptRowType.someValue4,
                           title: ARCHLocalizedStrings.someValue4)

        BottomOfReceiptRow(receiptViewModel: receiptViewModel,
                           type: ReceiptRowType.someValue5,
                           title: ARCHLocalizedStrings.someValue5)
    }
} // end bottomRow

Answer 2

尝试围绕您的观点创建一个群组 { }。 Swiftui 中只允许 10 个...有了组，您可以添加更多。或使用子视图...（代码也会更清晰）

SwiftUI：随机 "Extra argument in call" 错误

SwiftUI: Random "Extra argument in call" error

swiftui

combine

基本解决方案：

或者：