iOS RXSwift 5.4

connect

通知 ConnectableObservable 可以开始发出元素了

ConnectableObservable 和普通的 Observable 十分相似，不过在被订阅后不会发出元素，直到 connect 操作符被应用为止。这样一来你可以等所有观察者全部订阅完成后，才发出元素。

演示

let intSequence = Observable<Int>.interval(1, scheduler: MainScheduler.instance)

    .publish()

_ = intSequence

    .subscribe(onNext: { print("Subscription 1:, Event: \($0)") })

DispatchQueue.main.asyncAfter(deadline: .now() + 2) {
_ = intSequence.connect()

}

DispatchQueue.main.asyncAfter(deadline: .now() + 4) {
_ = intSequence

      .subscribe(onNext: { print("Subscription 2:, Event: \($0)") })

}

DispatchQueue.main.asyncAfter(deadline: .now() + 6) {
_ = intSequence

      .subscribe(onNext: { print("Subscription 3:, Event: \($0)") })

}

输出结果：

Subscription 1:, Event: 0
Subscription 1:, Event: 1
Subscription 2:, Event: 1
Subscription 1:, Event: 2
Subscription 2:, Event: 2
Subscription 1:, Event: 3
Subscription 2:, Event: 3
Subscription 3:, Event: 3
Subscription 1:, Event: 4
Subscription 2:, Event: 4
Subscription 3:, Event: 4
Subscription 1:, Event: 5
Subscription 2:, Event: 5
Subscription 3:, Event: 5
Subscription 1:, Event: 6
Subscription 2:, Event: 6
Subscription 3:, Event: 6

...

create

通过一个构建函数完整的创建一个 Observable

create 操作符将创建一个 Observable，你需要提供一个构建函数，在构建函数里面描述事件（next，error，completed）的产生过程。

通常情况下一个有限的序列，只会调用一次观察者的 onCompleted 或者 onError 方法。并且在调用它们后，不会再去调用观察者的其他方法。

演示

创建一个 [0, 1, ... 8, 9] 的序列：

let id = Observable<Int>.create { observer in

    observer.onNext(0)

    observer.onNext(1)

    observer.onNext(2)

    observer.onNext(3)

    observer.onNext(4)

    observer.onNext(5)

    observer.onNext(6)

    observer.onNext(7)

    observer.onNext(8)

    observer.onNext(9)

    observer.onCompleted()
return Disposables.create()

}