Using RxJava to fetch object, transform a containing list, and use the list

Question

The high level problem I'm trying to solve is transforming a list of Foo objects contained in a fetched FooContainer (Observable) to a list of FooBar objects using RxJava.

My (confused) attempt:

fooContainerObservable
  .map(container -> container.getFooList())
  .flatMap(foo -> transformFooToFooBar(foo))
  .collect( /* What do I do here? Is collect the correct thing? Should I be using lift? */)
  .subscribe(fooBarList -> /* Display the list */);

My confusion (or at least one point of it) is the step moving the flattened list back to a list.

Note: I'm attempting to do this in an Android app.

Could you explain why you plan to use collect? If you want to collect all items to a List, just call toList. — zsxwing
– zsxwing, Commented Dec 9, 2014 at 2:38
@zsxwing because it seemed to makes sense that I was "collect"ing multiple items from the stream of events :). I wasn't aware that toList existed. If you answer suggesting that, I'll mark it as the solution! — loeschg
– loeschg, Commented Dec 9, 2014 at 16:14

zsxwing · Accepted Answer · 2014-12-10 01:27:14Z

17

toList can collect all items of an Observable into a List and emit it. toList can be implemented using collect, but it's much easier than collect. For your example, it will be:

fooContainerObservable
  .map(container -> container.getFooList())
  .flatMap(foo -> transformFooToFooBar(foo))
  .toList()
  .subscribe(fooBarList -> /* Display the list */);

answered Dec 10, 2014 at 1:27

zsxwing

21k4 gold badges41 silver badges62 bronze badges

Sign up to request clarification or add additional context in comments.

Collectives™ on Stack Overflow

Using RxJava to fetch object, transform a containing list, and use the list

1 Answer 1

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

Comments

Your Answer

Sign up or log in

Post as a guest

Related