RxJava - emit an observable every second

I am making a timer in Android using RxJava. I need to make a timer in RxJava to emit an observable every second. I have tried the following but with no luck. Any thoughts on what I am doing wrong?

Observable.interval(1000L, TimeUnit.MILLISECONDS)
.timeInterval()
.observeOn(AndroidSchedulers.mainThread())
.subscribe({Log.d(LOG_TAG, "&&&& on timer") })

In your `subscribe()` you don't consume the `longTimeInterval` object that's returned by the `timeInterval()` operator.

Correct version:

.subscribe(longTimeInterval -> {
Log.d(LOG_TAG, "&&&& on timer");
}

Also I think you don't need the `timeInterval()` operator at all. `Observable.interval()` will emit an observable every second in your case, which I guess is what you want. `timeInterval()` transforms that to an observable that holds the exact time difference between two events occur, I doubt you'll need that.

Your code seems not to be called. Check whether it is executed and when. As of working with `Observable`, it is completely correct.

For example, I put your snippet inside `onCreate(...)` of my `MainActivity`:

override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
Observable.interval(1000L, TimeUnit.MILLISECONDS)
.timeInterval()
.observeOn(AndroidSchedulers.mainThread())
.subscribe { Log.d("tag", "&&&& on timer") }
// ...
}
And it works:

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Also, probably you don't need `.timeInterval()` because `Observable.interval(...)` itself emits sequential numbers within the specified rate, and `.timeInterval()` just transforms it to emit the time intervals elapsed between the emissions.

[1]:

In Kotlin & RxJava 2.0.2 simply define an Observable Interval with an `initialDelay` 0 and `period` 1 which will emit list item each second.

val list = IntRange(0, 9).toList()
val disposable = Observable
.interval(0,1, TimeUnit.SECONDS)
.map { i -> list[i.toInt()] }
.take(list.size.toLong())
.subscribe {
println("item: $it")
}
Thread.sleep(11000)