RxJava - emit an observable every second

Question

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") })

Answer 1

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:

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.