How to use RxSwift Observable.interval?

Question

I'm trying to emit a sequence on a ”pulse” at a given time interval. Totally new to everything Rx, but thought this would do it:

import RxSwift
let db = DisposeBag()

_ = Observable<Int>.interval(1.0, scheduler: MainScheduler.instance)
    .debug("interval")
    .subscribe(onNext: {
        print($0)
    })
    .addDisposableTo(db)

But it only outputs:

2017-09-25 06:12:41.161: interval -> subscribed

And nothing more. What am I not understanding here?

What's a lifetime of your dispose bag - `db`? Try again without this line: `.addDisposableTo(db)` — Nikita Ermolenko, Sep 25 '17 at 04:23
Tried it now. With or without `.addDisposable` it stil doesn't seem to emit anything. I've added the complete code in my playground now. The dispose bag should be alive. — PEZ, Sep 25 '17 at 06:28
I think it is latest, I have this in my Podfile: `pod 'RxSwift', '~> 3.0'` — PEZ, Sep 25 '17 at 07:55
Thanks for confirming that the code should work! I was starting to pull off all my hair here. — PEZ, Sep 25 '17 at 07:57

score 14 · Accepted Answer · answered Sep 25 '17 at 17:24

14

There is nothing wrong with your code. The dispose bag is alive as it should be. However, the playground execution ends as soon as the last instruction is run, hence the problem.

In order to tell the playground to continue running after everything was executed, you have to import PlaygroundSupport and tell the page to continue running:

import RxSwift
import PlaygroundSupport

let db = DisposeBag()

Observable<Int>.interval(1.0, scheduler: MainScheduler.instance)
    .debug("interval")
    .subscribe(onNext: {
        print($0)
    })
    .addDisposableTo(db)

PlaygroundPage.current.needsIndefiniteExecution = true

answered Sep 25 '17 at 17:24

iska

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3

in RxSwift5: ```Observable.interval(.seconds(1.0), scheduler: ...``` – yonivav May 05 '19 at 12:33
3

How could stop this timer? – Hamed Sep 21 '19 at 12:00
You create an instance of `var timerDisposable: Disposable?` and return the output if `Observable.interval(.seconds(1.0), scheduler: ...` to `timerDisposable`. Finally you can stop the timer by calling `timerDisposable?.dispose()`. – Maschina Mar 20 '20 at 19:37

How to use RxSwift Observable.interval?

1 Answers1