Question

我在iOS / Swift（ReactiveX）中使用RxSwift。

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，我不希望在动画结束前收到下一次更新（我不想放弃动画期间发生的更新）。

所以我需要的是暂停dataUpdates可观察的发光。

我怎样才能做到这一点？

Answer 1

使用BehaviorSubject创建一个暂停和恢复更新的阀门。请注意，您需要在dataUpdates中为阀门关闭时到达的更新提供一些背压支持（即缓冲）。

所以在伪代码中（我没有代码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))

ReactiveX如何暂停observable

1 个答案: