RxJava - Combining multiple/different web service calls

Question

I\'m working with the Basecamp api to return and display to do lists. Here\'s a sample of what I\'m doing at the moment:

bcxClient
  .fetchToDoLists()
  .subscri         


        

Answer 1

You should not "break the chain" in your RxJava calls, hence you will need flatMap to chain them. Also Observable.from() lets you split List of elements into separate Observables. Next, you can use toList to get elements back into list. Here's an example :

bcxClient
        .fetchToDoLists()
        .flatMap(new Func1<List<BcxToDoList>, Observable<BcxToDoList>>() {
            @Override
            public Observable<BcxToDoList> call(List<BcxToDoList> bcxToDoLists) {
                return Observable.from(bcxToDoLists);
            }
        })
        .flatMap(new Func1<BcxToDoList, Observable<List<BcxToDo>>>() {
            @Override
            public Observable<List<BcxToDo>> call(BcxToDoList bcxToDoList) {
                return bcxClient
                        .fetchToDos(bcxToDoList.bucket.id);
                        .map(new Func1<List<BcxToDo>, BcxToDoList>() {
                            @Override
                            public BcxToDoList call(List<BcxToDo> bcxToDos) {
                                bcxToDoList.toDos.addAll(bcxToDos);
                                return bcxToDoList;
                            }
                        });
            }
        })
        .toList()
        .subscribe(...);