CODEWITHSUNDEEP
androidrx-javarx-java2
SRKS
SRKS

Reputation: 218

RxJava Android - replace list with map or flatmap

I am pretty new to RxJava

I have an Observable

  private static rx.Observable<List<item>> getList() {
        return rx.Observable.fromCallable(() -> {
            call some internal methods
            return list;
        });
    }

I have a caller method

public static void getListFromObservable() {
        getList().subscribeOn(Schedulers.io())
         .observeOn(AndroidSchedulers.mainThread())
         .subscribe( new Subscriber<List<item>>() {
                @Override
                public void onCompleted() {}

                @Override
                public void onError(Throwable error) {}

                @Override
                public void onNext(List<item> i) {
                    for (item each : i) {
                           getSubdetails(each)
                          .subscribeOn(Schedulers.io())
                          .observeOn(AndroidSchedulers.mainThread())
                          .subscribe(new Subscriber<Boolean>() {

                           @Override
                           public void onCompleted() {}
                           @Override
                           public void onError(Throwable error) {  }
                           @Override
                           public void onNext(Boolean aBoolean) {}
                   });
      }

This is another observable

private static rx.Observable<Boolean>> getSubdetails(item i) {
            return rx.Observable.fromCallable(() -> {
                call some internal methods
                return true;
            });
        }

I do not want to use foreach in the OnNext, but I want to use Map or FlatMaps. Can someone help me on how to do this?

Upvotes: 0

Views: 1764

Answers (2)

Dmitriy Mitroshin
Dmitriy Mitroshin

Reputation: 26

You can try something like this:

getListObservable()
    ...
    .flatMap( listOfItems ->
        return Observable.fromIterable(listOfItems)
                    .concatMap(item -> getDetailsObservable(item))
                    .toList()
                    .toObservable()
    )
    .doOnNext { detailedListOfItems ->
        // Do Something with your detailed items
    }

There is a good book for beginners in RxJava https://www.manning.com/books/rxjava-for-android-developers I am not shore about the architect in that book. Especially with ViewModel, but many cool operators are explained very intuitive and graphically.

Difference between map and flatMap i finally understand with this book.

Upvotes: 0

akarnokd
akarnokd

Reputation: 70017

For example:

getList()
    .subscribeOn(Schedulers.io())
    .flatMapIterable(list -> list)
    .flatMap(each -> getSubdetails(each))
    .observeOn(AndroidSchedulers.mainThread())
    .subscribe(/* ... */);

Upvotes: 2

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