swift - 反应可可中的表单验证

Question

我正在尝试验证具有多个文本字段的表单。但我只能在编辑两个文本字段时观察......

let validUserNameSignal =
    self.nameTextField
        .reactive
        .continuousTextValues
        .skipNil()
        .map({ $0.characters.count > 3 })

let pwdPasswordFieldSignal = 
    self.lastnameTextField.reactive
        .continuousTextValues
        .skipNil()
        .map({$0.characters.count > 3})

let formValidation =  validUserNameSignal.combineLatest(with: pwdPasswordFieldSignal)

formValidation.observeValues { (userNameResult,pwdResult) in
    print(userNameResult)
    print(pwdResult)
}

我做的方式好吗还是有其他方式？

Answer 1

这是一个基本 ViewController 的示例实现，我整理了一些我认为可以做得更好的事情。

class ViewController: UIViewController {
    @IBOutlet weak var nameTextField: UITextField!
    @IBOutlet weak var passwordTextField: UITextField!

    func nameValidation(for field: UITextField) -> Signal<Bool, NoError> {
        return field
            .reactive
            .continuousTextValues
            .skipNil()
            .map { $0.characters.count > 3 }
    }

    override func viewDidLoad() {
        super.viewDidLoad()

        let validUserNameSignal = nameValidation(for: nameTextField)
        let lastNameFieldSignal = nameValidation(for: lastNameTextField)
        let formValidation =
            SignalProducer(signal: validUserNameSignal.combineLatest(with: lastNameFieldSignal))
                .map { $0 && $1 }
                .prefix(value: false)

        formValidation.startWithValues {
            print($0)
        }
    }
}

Answer 2

continuousTextValues是 a Signal，它具有热语义。这意味着它只发出观察后发生的变化。

您可能希望将您的formValidation信号转换为生产者，并为默认值添加前缀。

SignalProducer(signal: formValidation)
    .map { $0 && $1 }
    .prefix(value: false)
    .startWithValues { ... }