How can I recheck every 1 second using RxJava?

Question

Is there any method in RxJava to recheck if the variable is null or not, For example, Recheck every 1 second or when the value is given to the variable?

String x;

Completable.create(emitter -> {
    if (x != null)
        emitter.onComplete();
}).timeout(10, TimeUnit.SECONDS).subscribe();

Answer 1

Yes, start an interval and read the value of the variable in some other operator. Note though that you'll need a volatile variable to be safe:

volatile String x;

Observable.interval(1, TimeUnit.SECONDS)
.takeUntil(t -> x != null)
.ignoreElements()
.subscribe(() -> System.out.println("Done!"));

Observable.timer(3500, TimeUnit.MILLISECONDS)
.subscribe(t -> { x = "value"; });