在UIKit中使用Combine验证并提交表单

我正在使用 Storyboard(UIKit) 构建表单。我有 4 个输入字段，当它有效时，我会将数据提交到 UI 并在 UI 上显示响应。我创建了一个 ViewModel 并在其中添加了验证代码。以下是我的验证代码：

@Published public var firstName = ""
    @Published public var lastName = ""
    @Published public var phoneNumber = ""
    @Published public var emailAddress = ""    
var isFirstNameValidPublisher: AnyPublisher<Bool, Never> {
        $firstName
            .map { name in
                return name.count >= 3
            }
            .eraseToAnyPublisher()
    }
    
    var isLastNameValidPublisher: AnyPublisher<Bool, Never> {
        $lastName
            .map { name in
                return name.count >= 3
            }
            .eraseToAnyPublisher()
    }
    
    var isUserEmailValidPublisher: AnyPublisher<Bool, Never> {
          $emailAddress
              .map { email in
                  let emailPredicate = NSPredicate(format:"SELF MATCHES %@", "[A-Z0-9a-z._%+-]+@[A-Za-z0-9.-]+\\.[A-Za-z]{2,64}")
                  return emailPredicate.evaluate(with: email)
              }
              .eraseToAnyPublisher()
      }
      
      var isPhoneNumberValidPublisher: AnyPublisher<Bool, Never> {
          $phoneNumber
              .map { phoneNumber in
                  return phoneNumber.count >= 8
              }
              .eraseToAnyPublisher()
      }
    
    public func isValidForm(firstName: String, lastName: String, phoneNum: String, emailAddress: String, isConsent: Bool) -> AnyPublisher<Bool, Never> {
        self.firstName = firstName
        self.lastName = lastName
        self.phoneNumber = phoneNum
        self.emailAddress = emailAddress
        
        return Publishers.CombineLatest4(
          isFirstNameValidPublisher,
          isLastNameValidPublisher,
          isUserEmailValidPublisher,
          isPhoneNumberValidPublisher)
            .map { isFirstNameValid, isLastNameValid, isPhoneNumberValid, isEmailValid in
                return isFirstNameValid && isLastNameValid && isPhoneNumberValid && isEmailValid && isConsent
            }
            .eraseToAnyPublisher()
    }

我试图在我的 ViewController 中单击提交按钮时使用它，如下所示：

cancellable = dependencies.leadConsumptionUseCase.isValidForm(firstName: firstNameTextView.text, lastName: lastNameTextView.text, phoneNum: phoneNumberTextView.text, emailAddress: emailTextView.text, isConsent: true).collect().sink(receiveCompletion: { completion in
        print("completed")
        print(completion)
    }, receiveValue: { res in
        print("result")
        print(res)
    })

我能够验证 ViewModel 中的字段，但不知怎的，我在 ViewController 中没有得到任何响应。 另外我不知道应该如何以及在哪里添加 api 调用。我已经创建了另一个服务类，其中有一个 api 调用，它将返回作为 AnyCancellable 的响应。 大多数相关示例都使用 SwiftUI，但我没有使用 SwiftUI。

Edit:从 isValidForm 函数调用中删除收集后，我能够获得响应，但现在它会出现多次。因此，我的 api 调用会执行多次。

下面有一个如何使用此代码的工作示例。

isValidForm()现在只返回发布者，它不接受值。您尝试验证的值通过您构建的四个流传入。

正如我所建议的，我已经包括了.print运算符，以便您可以在调试输出中看到每个流如何参与验证。

在操场的主体中，我一次将一个值发送到四个流中。当发送每个值时，isValidForm()发布者发出false值，直到所有字段都已发送。然后它会发出一个true让您知道所有四个字段都有有效值。

import UIKit
import Combine

class Form : ObservableObject {
    @Published public var firstName = ""
    @Published public var lastName = ""
    @Published public var phoneNumber = ""
    @Published public var emailAddress = ""

    var isFirstNameValidPublisher: AnyPublisher<Bool, Never> {
            $firstName
                .map { name in
                    return name.count >= 3
                }
                .eraseToAnyPublisher()
        }
        
        var isLastNameValidPublisher: AnyPublisher<Bool, Never> {
            $lastName
                .map { name in
                    return name.count >= 3
                }
                .eraseToAnyPublisher()
        }
        
        var isUserEmailValidPublisher: AnyPublisher<Bool, Never> {
              $emailAddress
                  .map { email in
                      let emailPredicate = NSPredicate(format:"SELF MATCHES %@", "[A-Z0-9a-z._%+-]+@[A-Za-z0-9.-]+\\.[A-Za-z]{2,64}")
                      return emailPredicate.evaluate(with: email)
                  }
                  .eraseToAnyPublisher()
          }
          
          var isPhoneNumberValidPublisher: AnyPublisher<Bool, Never> {
              $phoneNumber
                  .map { phoneNumber in
                      return phoneNumber.count >= 8
                  }
                  .eraseToAnyPublisher()
          }
        
        public func isValidForm() -> AnyPublisher<Bool, Never> {
            return Publishers.CombineLatest4(
                isFirstNameValidPublisher.print("first name"),
              isLastNameValidPublisher.print("last name"),
              isUserEmailValidPublisher.print("email"),
              isPhoneNumberValidPublisher.print("phone"))
                .map { isFirstNameValid, isLastNameValid, isPhoneNumberValid, isEmailValid in
                    return isFirstNameValid && isLastNameValid && isPhoneNumberValid && isEmailValid
                }
                .print("isValidForm")
                .eraseToAnyPublisher()
        }
}

let form = Form()
let validWatcher = form.isValidForm().sink { isValid in
    print("Is the form valid?: \(isValid)")
}
form.firstName = "Scott"
form.lastName = "Thompson"
form.phoneNumber = "(123) 555-1234}"
form.emailAddress = "[email protected] /cdn-cgi/l/email-protection"