subscribeOn Android UI thread

Question

I am new to RxJava and I think I am probably overlooking something very basic. So I have created an Observable that performs a long running I/O task like this. Now I want to make sure that subscriber receives its result on Android UI Thread:

Observable.create(new ObservableOnSubscribe<Device>() {
    @Override
    public void subscribe(@io.reactivex.annotations.NonNull final ObservableEmitter<Device> e) throws Exception {
        //Long running task
    }
}).subscribeOn(Schedulers.io())

As you can see, I have performed the long running task on Schedulers.io(). How do I switch back to Android UI thread?

I know about `observeOn`. Is there any other workaround aside from using another library? — Dhruv Jagetiya, Oct 06 '17 at 11:45
use the RxAndroid lib. It is only 1 or 2 methods, so not downsides to using it — Tim, Oct 06 '17 at 11:48
Of course, you have another solution - you can implement your own Scheduler with main thread looper. Look into RxAndroid for example =) But why you need to re-invent a bicycle, if you have the ability to load simple and light-weight library? — Pavel Strelchenko, Oct 06 '17 at 12:54

score 16 · Accepted Answer · answered Oct 06 '17 at 11:43

16

You have to perform observeOn(AndroidSchedulers.mainThread()).

answered Oct 06 '17 at 11:43

azizbekian

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There is no `AndroidSchedulers` class. – Dhruv Jagetiya Oct 06 '17 at 11:45
3

You have to import [`RxAndroid`](https://github.com/ReactiveX/RxAndroid) in gradle file: `compile 'io.reactivex.rxjava2:rxandroid:2.0.1'` – azizbekian Oct 06 '17 at 11:46
Fascinating. I was reluctant to include another library, but it seems like it's very lightweight. – Dhruv Jagetiya Oct 06 '17 at 11:49
If you don't want to import that lib (but I suggest you to do it) just pass a scheduler construct with the main looper – Mathieu Bertin Oct 06 '17 at 11:51
1

@MathieuBertin Then why use RxAndroid at all? – Dhruv Jagetiya Oct 06 '17 at 11:55
Because it's just sugar but it's really usefull and it's really light. Moreover you have to implement your proper version of scheduler and it could not work properly instead of the 'AndroidSchedulers'' – Mathieu Bertin Oct 06 '17 at 11:57

subscribeOn Android UI thread

1 Answers1