UIButton 上的 RxSwift 和 isSelected 属性

Question

我有三个按钮，我希望一次只选择一个：

和：

等...

我的做法是这样的：

class MyController: UIViewController {

    @IBOutlet var buttonOne: UIButton!
    @IBOutlet var buttonTwo: UIButton!
    @IBOutlet var buttonThree: UIButton!

    var buttonOneIsSelected = Variable(true)
    var buttonTwoIsSelected = Variable(false)
    var buttonThreeIsSelected = Variable(false)


    override func viewDidLoad() {
        super.viewDidLoad()

        buttonOne.isSelected = true

        buttonOneIsSelected.asDriver()
            .drive(buttonOne.rx.isSelected)
            .disposed(by: disposeBag)
        buttonTwoIsSelected.asDriver()
            .drive(buttonTwo.rx.isSelected)
            .disposed(by: disposeBag)
        buttonThreeIsSelected.asDriver()
            .drive(buttonThree.rx.isSelected)
            .disposed(by: disposeBag)

        buttonOne.rx.tap.asObservable().map { (_) -> Bool in
            return !self.buttonOne.isSelected
        }
        .do(onNext: { (isSelected) in
            self.buttonTwoIsSelected.value = !isSelected
            self.buttonThreeIsSelected.value = !isSelected
        })
        .bindTo(buttonOne.rx.isSelected)
        .disposed(by: disposeBag)

        buttonTwo.rx.tap.asObservable().map { (_) -> Bool in
            return !self.buttonTwo.isSelected
            }
            .do(onNext: { (isSelected) in
                self.buttonOneIsSelected.value = !isSelected
                self.buttonThreeIsSelected.value = !isSelected
            })
            .bindTo(buttonTwo.rx.isSelected)
            .disposed(by: disposeBag)

        buttonThree.rx.tap.asObservable().map { (_) -> Bool in
            return !self.buttonThree.isSelected
            }
            .do(onNext: { (isSelected) in
                self.buttonOneIsSelected.value = !isSelected
                self.buttonTwoIsSelected.value = !isSelected
            })
            .bindTo(buttonThree.rx.isSelected)
            .disposed(by: disposeBag)
}

有没有更好的方法？它有效，但是有没有更好的 'reactive' 方法通过使用 RxSwift 来做到这一点？

Answer 1

Subject 和扩展 Variable 大多数时候仅在从命令式世界过渡到反应式世界时有用。在这里，你可以没有它们。

.do(onNext:) 也是一种执行副作用的方法，这是您在反应式代码中通常不希望看到的。

// force unwrap to avoid having to deal with optionals later on
let buttons = [button1, button2, button3].map { [=10=]! }

// create an observable that will emit the last tapped button (which is
// the one we want selected)
let selectedButton = Observable.from(
  buttons.map { button in button.rx.tap.map { button } }
).merge()

// for each button, create a subscription that will set its `isSelected`
// state on or off if it is the one emmited by selectedButton
buttons.reduce(Disposables.create()) { disposable, button in
    let subscription = selectedButton.map { [=10=] == button }
      .bindTo(button.rx.isSelected)

    // combine two disposable together so that we can simply call
    // .dispose() and the result of reduce if we want to stop all
    // subscriptions
    return Disposables.create(disposable, subscription)
}
.addDisposableTo(disposeBag)

UIButton 上的 RxSwift 和 isSelected 属性

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