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我在 iOS/Swift ( RxSwift )中使用ReactiveX 。

假设我有一个可观察的：

let dataUpdates = ...

我订阅了：

dataUpdates.subscribeNext({ data in
    // update tableView with data
    // maybe move to a difference cell with an animation
})

如果我在制作动画时收到更新，我不想在动画完成之前收到下一次更新（我也不想丢失动画期间发生的更新）。

所以我只需要暂停那个dataUpdates可观察的发射。

我怎样才能做到这一点？

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1 回答 1

2

使用 BehaviorSubject 创建一个暂停和恢复更新的阀门。dataUpdates请注意，当阀门关闭时，您将需要一些背压支持（即缓冲）来获取更新。

所以在伪代码中（我不编码 switft，所以请原谅我的语法）

// create a BehaviorSubject with default value true. It will always emit
// the latest value when subscribed to, thus it is kind of a variable
let valve = BehaviorSubject(value: true)

// we are only interested to get one `true` value. When the latest value
// received by the valve is `true`, this will give a value immediately when
// subscribed to. When the latest value is `false`, this will not give
// any events until it is true.
let openValve = valve.filter{$0}.take(1)

// for each data update, pass it through if the valve is open and otherwise
// start waiting for it to turn true
let pauseableDataUpdates = dataUpdates.concatMap{update in openValve.map { _ in update}}

// now when you start rendering, you do
valve.on(.Next(false))

// and after animation is done, you do
valve.on(.Next(true))
于 2017-06-04T07:41:26.230 回答