Question

我在项目中使用RxSwift和RxCocoa。

我有一个UITextField名为“ lastNameTF”，还有一个UILabel名为“ lastNameTitle”。

我想知道是否有任何方法可以使用isHidden将lastNameTitle的isHidden值设置为等于lastNameTF的RxSwift值。

Answer 1

我相信您可以按照此处所述使用KVO- https://github.com/ReactiveX/RxSwift/blob/master/Documentation/GettingStarted.md#kvo

Answer 2

使用KVO非常容易。 Here is an example完全是您要尝试做的事情，而无需使用RxSwift（不知道那是什么...）

这是要点

class ViewController: UIViewController {
    private var lastNameTextFieldHiddenContext = 0
    private var lastNameObservingView:UIView? = nil
    @IBOutlet weak var lastNameLabel: UILabel!
    @IBOutlet weak var lastNameTextField: UITextField!

    override func viewDidLoad() {
        super.viewDidLoad()
        // add the observer
        lastNameTextField.addObserver(
            self,
            forKeyPath: "hidden",
            options: [.new],
            context: &self.lastNameTextFieldHiddenContext
        )
    }

    /// function will be called whenever an added observer is triggered
    override func observeValue(
        forKeyPath keyPath: String?,
        of object: Any?,
        change: [NSKeyValueChangeKey : Any]?,
        context: UnsafeMutableRawPointer?
    ) {
        // make sure it is our text field isHidden observer
        if context == &self.lastNameTextFieldHiddenContext {
            // get the new value that was set
            if let newValue = change?[NSKeyValueChangeKey.newKey] as? Bool {
                // do what needs to be done when the observer is triggered
                self.lastNameLabel.isHidden = newValue
            }
        }
    }

    deinit {
        // remove the observer
        if let view = self.lastNameObservingView {
            view.removeObserver(self, forKeyPath: "hidden")
            self.lastNameObservingView = nil
        }
    }

    @IBAction func showHideButtonAction(_ sender: Any) {
        self.lastNameTextField.isHidden = !self.lastNameTextField.isHidden
    }
}

Answer 3

如果您仍然需要简单的RxSwift方法，请尝试以下操作：

// Controls are visible by default (isHidden = false)
let isControlHidden = BehaviorRelay<Bool>(value: false)

override func viewDidLoad() {
  super.viewDidLoad()

  let isHiddenDriver = self.isControlHidden.asDriver()

  isHiddenDriver
    .drive(self.lastNameTitle.rx.isHidden)
    .disposed(by: disposeBag)

  isHiddenDriver
    .drive(self.lastNameTF.rx.isHidden)
    .disposed(by: disposeBag)
}

由于两个控件的可视性都需要彼此绑定，因此可以使用“主题”或“中继”来实现，在这种情况下为“ ControlHidden”。因此，如果您想显示/隐藏它，则只需发出一个新信号：

@IBAction func hide(_ sender: Any) {
  self.isControlHidden.accept(true)
}

@IBAction func show(_ sender: Any) {
  self.isControlHidden.accept(false)
}

RxSwift-使一个UI元素根据其他元素隐藏/不隐藏

3 个答案: