ios - ReactiveCocoa 5 动画

Question

在通过 ReactiveSwift Signal Producer 向 View 的 alpha 属性发送一些值后，我尝试对 View 的 alpha 属性进行动画。

以下是我目前在没有动画的情况下的做法。

// Somewhere in View Model (for all code below)
let shouldShowShutter = MutableProperty<Bool>(false)

// In my View
self.shutterButton.reactive.alpha <~ self.viewModel.shouldShowShutter.map({ (show) -> CGFloat in
        return show ? 1:0.0
    })

我可以通过以下方式不优雅地为 View 设置动画:

self.viewModel.shouldShowShutter.producer.startWithSignal { (observer, disposable) in
            observer.map({ (show) -> CGFloat in
                return show ? 1:0.0
            }).observeValues({ [unowned self] (alpha) in
                UIView.animate(withDuration: 0.5, animations: { 
                    self.shutterButton.alpha = alpha
                })
            })
        }

但我应该能够使用 ReactiveAnimation 为 View 添加动画:

self.shutterButton.reactive.alpha <~ self.viewModel.shouldShowShutter.map({ (show) -> CGFloat in
        return show ? 1:0.0
    }).animateEach(duration: 0.2).join(.Concat)

问题:在我提出问题时，ReactiveCocoaLayout 和 ReactiveAnimation 似乎都不再工作了，至少在 Swift 3 或 ReactiveCocoa 5，因为它们很大程度上依赖于遗留的 RACSignals。

是否有更优雅的方式使用 ReactiveCocoa 5 将信号流动画化到 ReactiveCocoa 组件？

Answer 1

我以前不知道 ReactiveAnimation，但我真的很喜欢这种方法。

所以我将其更新为 RAC 5.0/Swift 3.2，看看 my fork 。我还将创建一个拉取请求，让我们看看是否能让项目恢复生机。

我包含了一个小型 iOS 演示项目来演示其用法:

label.reactive.center <~ SignalProducer.timer(interval: .seconds(1), on: QueueScheduler.main)
  .map { _ in return self.randomPoint() }
  // In order to demonstrate different flatten strategies,
  // the animation duration is larger than the animation interval,
  // thus a new animation begins before the running animation is finished
  .animateEach(duration: 1.5, curve: .EaseInOut)
  // With the .concat flatten strategy, each animations are concatenated.
  // Each animation finisheds, before the next one starts.
  // This also means, that animations are queued
  .flatten(.concat)
  // With the .merge flatten strategy, each animation is performed immediately
  // If an animation is currently running, it is cancelled and the next animation starts from the current animation state
  //.flatten(.merge)