对成员“buildBlock()”的引用不明确（最大子视图限制？）

Question

我一直在尝试使用 Swift UI 为 iOS 13 制作一个应用程序，但我不断收到这个奇怪的错误：“对成员‘buildBlock()’的引用不明确”。

无论我做什么，错误都不会消失。

我尝试一次对部分代码进行注释，以查看哪一部分可能导致了问题，但唯一有效的方法是注释掉整个视图。

我尝试清理构建文件夹并删除派生数据。我也尝试多次重新启动我的电脑和 Xcode，但没有任何解决办法。

我很确定这只是一个 Xcode 错误，但一定有办法解决它，如果有人能告诉我那是什么，我将非常感激。

var body: some View {
    GeometryReader { geometry in {
        VStack {
            Button (action: self.editProfilePicture) {
                    Image(ImageNames.AccountIconImageName, bundle: Bundle.main)
                        .resizable()
                        .frame(width: geometry.size.width / SizeConstants.AccountIconSizeDiviser, height: geometry.size.width / SizeConstants.AccountIconSizeDiviser)
                        .padding()
                        .background(ColorConstants.VeryLightGrayColor)
                        .clipShape(Circle())
                }
                .accentColor(.white)
                .padding(.bottom, LargePadding)
                
                ScrollView (showsVerticalIndicator: false) {
                    
                    let const: Length? = geometry.size.width - SizeConstants.FullNameTextFieldWidthReduction
                    
                    TextBox(textBinding: self.$fullName, placeHolder: Text(Strings.FullNameString), editChanged: self.fullNameChanged)/*.padding(.bottom, SmallPadding)*/.frame(width: const)
                    TextBox(textBinding: self.$username, placeHolder: Text(Strings.UsernameString), editChanged: self.usernameChanged)//.padding(.bottom)

                    Text(verbatim: Strings.ChooseIdType).font(.footnote).color(.gray)

                    TextBox(textBinding: self.$phoneNumber, placeHolder: Text(Strings.PhoneNumberString), editChanged: self.phoneNumberChanged)//.padding(.bottom, SmallPadding)
                    TextBox(textBinding: self.$emailAddress, placeHolder: Text(Strings.EmailAddressString), editChanged: self.emailAddressChanged)//.padding(.bottom)

                    Spacer(minLength: PaddingConstants.FirstSignupSpacerMinSize)

                    TextBox(textBinding: self.$password, placeHolder: Text(Strings.PasswordFieldPlaceHolder), editChanged: self.signupPasswordChanged)//.padding(.bottom, SmallPadding)
                    TextBox(textBinding: self.$confirmPassword, placeHolder: Text(Strings.ConfirmPasswordString), editChanged: self.confirmPasswordChanged)//.padding(.bottom)

                    Spacer(minLength: PaddingConstants.SecondSignupSpacerMinSize)

                    Button (action: self.signup) {
                        Text(Strings.CreateAccountString).color(.white).font(Font.system(size: SizeConstants.LoginButtonFontSize))
                    }
                    .padding(EdgeInsets(top: PaddingConstants.CreatAccountButtonVerticalPadding,
                                        leading: PaddingConstants.CreateAccountButtonSidePadding,
                                        bottom: PaddingConstants.CreatAccountButtonVerticalPadding,
                                        trailing: PaddingConstants.CreateAccountButtonSidePadding))
                    .background(LeznoBlue)
                    .clipShape(RoundedRectangle(cornerRadius: SmallCornerRadius))
                    
                    Spacer(minLength: PaddingConstants.ThirdSignupSpacerMinSize)
                    
                    Text(Strings.AgreementString)
                    
                    HStack {
                        Button (action: {}) {
                            Text(Strings.TermsString)
                        }
                        Text(Strings.AndString)
                        Button (action: {}) {
                            Text(Strings.PrivacyString)
                        }
                    }
                    
                }
        }
        .padding()
    }
}

编辑：

事实证明，我忘记了在视图生成器闭包中最多只能有 10 个视图，而我的视图不止于此。只需将它们分组以减少观看次数即可解决该错误。

事实证明，Xcode 显示的错误非常具有误导性。

感谢哈米什指出这一点

Answer 1

正如 @Hamish 最初在评论中提到的，ViewBuilder 不能超过 10 个子视图！因此，您应该将项目分成较小的部分，并尝试按组添加它们。

所以不要这样：（这是一个基于您的原始代码的工作示例，不完全相同）

struct ContentView : View {
    
    @State var firstName: String = ""
    @State var lastName: String = ""
    
    @State var phoneNumber: String = ""
    @State var emailAddress: String = ""
    
    @State var password: String = ""
    @State var confirmPassword: String = ""
    
    var body: some View {
        
        ScrollView (showsVerticalIndicator: false) {
            
            TextField($firstName, placeholder: Text("First Name"))
            TextField($lastName, placeholder: Text("Last Name"))

            Spacer()
            
            TextField($phoneNumber, placeholder: Text("Phone Number"))
            TextField($emailAddress, placeholder: Text("Email Address"))
            
            Spacer()
            
            TextField($password, placeholder: Text("Password"))
            TextField($confirmPassword, placeholder: Text("Confirm Password"))
            
            // ...
            
        }
        .padding()
    }
    
}

考虑将其分成有意义的小组，如下所示：

struct NameSectionView : View {
    
    @State var firstName: String
    @State var lastName: String
    
    var body: some View {
        Group {
            TextField($firstName, placeholder: Text("First Name"))
            TextField($lastName, placeholder: Text("Last Name"))
        }
    }
    
}

struct ContactSectionView : View {
    
    @State var phoneNumber: String
    @State var emailAddress: String
    
    var body: some View {
        Group {
            TextField($phoneNumber, placeholder: Text("Phone Number"))
            TextField($emailAddress, placeholder: Text("Email Address"))
        }
    }
    
}

struct PasswordSectionView : View {
    
    @State var password: String
    @State var confirmPassword: String
    
    var body: some View {
        Group {
            TextField($password, placeholder: Text("Password"))
            TextField($confirmPassword, placeholder: Text("Confirm Password"))
        }
    }
    
}

并像这样使用它们：

struct ContentView : View {
    
    @State var firstName: String = ""
    @State var lastName: String = ""
    
    @State var phoneNumber: String = ""
    @State var emailAddress: String = ""
    
    @State var password: String = ""
    @State var confirmPassword: String = ""
    
    var body: some View {
        
        ScrollView (showsVerticalIndicator: false) {
            
            NameSectionView(firstName: firstName, lastName: lastName)

            Spacer()
            
            ContactSectionView(phoneNumber: phoneNumber, emailAddress: emailAddress)
            
            Spacer()
            
            PasswordSectionView(password: password, confirmPassword: confirmPassword)
            
            // ...
            
        }
        .padding()
    }
    
}

此外，如果您想在其他地方使用其中任何一个，这也更可重用。