Question

我一直在尝试使用Swift UI为iOS 13创建一个应用程序，但我一直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。

我尝试一次注释部分代码，以查看可能是引起该问题的部分，但唯一可行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。我还尝试过多次重启计算机和Xcode，但没有任何修复措施。

我很确定这只是一个Xcode错误，但是必须解决它，如果有人能告诉我那是什么，我将不胜感激。

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()
    }
}

Screenshot of the error

编辑：

因此，事实证明我忘记了在视图构建器关闭中最多只能有10个视图，而我拥有的更多。只需将它们分组以减少视图计数即可解决错误。

事实证明，Xcode显示的错误极具误导性。

感谢Hamish指出

Answer 1

正如@Hamish在评论中最初提到的，ViewBuilder的子视图限制不能超过10个！因此，您应该将项目分成较小的部分，并尝试按组逐个添加。

所以不是这样的：（这是一个基于原始代码的有效示例，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较小的小组，例如：

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()
    }

}

如果您想在其他任何地方使用这些工具中的任何一个，这也更可重用。

对成员'buildBlock（）'的含糊不清的引用

1 个答案: