RxJava and Retrofit - first steps with Rx

Question

With RxJava (without Retrolambda), I would like to do some API calls and complete my data with it. My incomplete object is a 'TvShow' with a list of object 'Season'. This 'Season' is empty and I need to complete it with episodes.

Observable<TvShow> getDataTVShow(long idTvShow)
//get TvShow with empty seasons (except season number)

Observable<Season> getDataSeason(long idTvShow, int seasonNumber); 
//get one complete season with episodes

So I want to:

Get my 'TvShow' object (OK)
Iterate over seasons (List <\Season>) from my 'TvShow' object and do for each season an API call to get my season fully completed and update my 'old' season in the list.
Then once we have all we need, persist data into the database (subscriber part)

Until now, I only have :

Observable<TvShow> = apiService.getDataTvShow(idTvShow)

I need now to iterate over seasons, I tried to use operator 'map' to switch from 'TvShow' object to my list of seasons (tvShow.getSeasons()) but I'm not sure to be in the good way. Beside that, I know 'doOnNext' will be used to update my 'old' season, that's it.

I tried to work with this good example: Handling lists with RxJava and Retrofit in android but I'm still stuck :(

If you can help me solve this problem, it would be great :)

zella zella · Accepted Answer · 2015-09-24T12:47:20

For example you have two observables:

Observable<Season> getSeason(int id)
Observable<TvShow> getTvShow(String id)

How load TvShow then load each Season and fill TvShow:

  Observable<TvShow> getFilledTvShow = getTvShow("123")
      .flatMap(tvShow ->
              //make stream observable from seasons
              Observable.from(tvShow.seasons)
                  //load each season from network
                  .flatMap(season -> getSeason(season.id))
                      //then collect all results to ArrayList
                  .collect(() -> new ArrayList<Season>(),
                      (seasons, filledSeason) -> seasons.add(filledSeason))
                      //finally fill tvShow and return it
                  .map(filledSeasons_ -> {
                     tvShow.seasons = filledSeasons_;
                     return tvShow;
                  })
      );

RxJava and Retrofit - first steps with Rx

1 Answers