Reactive

Programming

a = b + c

The learning curve

Reactive

Programming

Reactive

Programming

"Programar con flujos asincronos de datos"

Data

Stream

Iterables

for (Cat cat : cats) {
    Log.i(TAG, cat.getName());
}

Data

Stream

Iterables

for (Iterator<Cats> iterator = cats.iterator(); 
                    iterator.hasNext();) {
    Cat cat = iterator.next();
    Log.i(TAG, cat.getName());
}

Data

Stream

Observables

"La llave está en el acceso a los datos"

Observables

Request

Request

Request

Request

Request

729

86

163

84

114

Story

Story

Story

Story

Story

storyObservable

Observers

729

86

163

84

114

¿Y ahora como accedo a esos datos?

storyObserver.subscribe(new Observer<Story>() {

    @Override
    public void onCompleted() {}

    @Override
    public void onNext(Story story) {
        Log.i(TAG, story.getTitle());
    }

    @Override
    public void onError(Throwable e) {
        e.printStackTrace();
    }

});

Creación de observable

729

163

Observable.create(new Observable.OnSubscribe<Story>() { //1
    @Override
    public void call(Subscriber<? super Story> subscriber) {
        if (!subscriber.isUnsubscribed()) { //2
            try {
                Story topStory = hackerNewsRestAdapter
                                    .getTopStory(); //3

                subscriber.onNext(topStory); //4
                
                Story newestStory = hackerNewsRestAdapter
                                    .getNewestStory();
                
                subscriber.onNext(newestStory);
                subscriber.onCompleted(); //5
            } catch (JsonParseException e) {
                subscriber.onError(e); //6
            }
        }
    }
});

topStory

newestStory

Subscriber implements Observer<Story>

Schedulers

¿Y dónde quedo lo asincrono?

Observable.create(new Observable.OnSubscribe<Story>() {
    //...
})
.subscribeOn(Schedulers.io())
.observeOn(AndroidSchedulers.mainThread());

729

163

topStory

newestStory

729

163

topStory

newestStory

Operators

Convirtiendo datos

changeColor(circle,Color.RED)

Operators

Convirtiendo datos

729

86

163

84

114

Story

Story

Story

Story

Story

Map

Author

Author

Author

Author

Author

Observable.create(new Observable.OnSubscribe<Story>() {
    //Emitting story objects...
})
.map(new Func1<Story, Author>() { 
    @Override 
    public Author call(Story story) {
        return story.getAuthor();
    }
})

Operators

Convirtiendo datos

729

86

163

84

114

Story

Story

Story

Story

Story

flatMap

Observable.create(new Observable.OnSubscribe<Story>() {
    //Emitting story objects...
})
.flatMap(new Func1<Story, Observable<Comment>>() { 
    @Override 
    public Observable<Comment> call(Story story) {
        return Observable.from(story.getComments());
    }
})

Operators

729

86

163

84

114

Story

Story

Story

Story

Story

Map

Author

Author

Author

Author

Author

Observable.create(new Observable.OnSubscribe<Story>() {
    //Emitting story objects...
})
.map(new Func1<Story, Author>() { 
    @Override 
    public Author call(Story story) {
        return story.getAuthor();
    }
})
.filter(new Func1<Author, Boolean>() {
        @Override
        public Boolean call(Author author) {
            return author.isCage();
        }
})

Filter

Android 
Examples

Retrolambda

 Observable.just(1,2,3,4)
            .first()
            .subscribe(new Action1<Integer>() {
                @Override
                public void call(Integer integer) {
                    System.out.print(integer);
                }
            });

Observable.just(1,2,3,4)
            .first()
            .subscribe(integer -> {
                System.out.print(integer);
            });

Observable.just(1,2,3,4)
                .first()
                .subscribe(System.out::print);

Android 
Examples

RxBinding

RxView.clicks(submitButton)
      .subscribe(o -> log("submit button clicked!"));

RxTextView.textChangeEvents(editText)
   .subscribe(e -> log(e.text().toString()));

emailChangeObservable = RxTextView.textChangeEvents(email);
    passwordChangeObservable = RxTextView.textChangeEvents(password);

    // force-disable the button
    submitButton.setEnabled(false);

    Observable.combineLatest(emailChangeObservable, passwordChangeObservable, 
    (emailObservable,passwordObservable) -> {
        boolean emailCheck = emailObservable.text().length() >= 3;
        boolean passwordCheck = passwordObservable.text().length() >= 3;
        return emailCheck && passwordCheck;
    }).subscribe(aBoolean -> {
        submitButton.setEnabled(aBoolean);
    });

Android 
Examples

Retrofit

@GET(SpotifyApiConstants.ARTIST_SEARCH_URL)
Observable<ArtistSearchResponse> searchArtist(
          @Query(SpotifyApiConstants.QUERY_TO_SEARCH) String query);

Android 
Examples

Retrofit

@GET(SpotifyApiConstants.ARTIST_SEARCH_URL)
Observable<ArtistSearchResponse> searchArtist(
          @Query(SpotifyApiConstants.QUERY_TO_SEARCH) String query);

myObservable.subscribe(onNextAction, onErrorAction, onCompleteAction);

Android 
Examples

Retrofit

@GET(SpotifyApiConstants.ARTIST_SEARCH_URL)
Observable<ArtistSearchResponse> searchArtist(
          @Query(SpotifyApiConstants.QUERY_TO_SEARCH) String query);

apiService.searchArtist(query)
        .observeOn(AndroidSchedulers.mainThread())
        .subscribe(new Action1<ArtistSearchResponse>() {
            @Override
            public void call(ArtistSearchResponse artistSearchResponse) {
                artistSearchResponse.getArtists();
            }
        }, new Action1<Throwable>() {
            @Override
            public void call(Throwable throwable) {
                throwable.printStackTrace();
            }
        });

myObservable.subscribe(onNextAction, onErrorAction, onCompleteAction);

Android 
Examples

Retrofit

@GET(SpotifyApiConstants.ARTIST_SEARCH_URL)
Observable<ArtistSearchResponse> searchArtist(
          @Query(SpotifyApiConstants.QUERY_TO_SEARCH) String query);

apiService.searchArtist(query)
                .observeOn(AndroidSchedulers.mainThread())
                .subscribe(
                        ArtistSearchResponse::getArtists,
                        Throwable::printStackTrace);

myObservable.subscribe(onNextAction, onErrorAction, onCompleteAction);

Android 
Examples

Retrofit

apiService.searchArtist(query)
    .observeOn(AndroidSchedulers.mainThread())
    .flatMap(artistSearchResponse -> 
            Observable.from(artistSearchResponse.getArtists()))
    .map(artist -> 
            apiService.getArtistBio(artist.getName()))
    .subscribe(bio -> bio.getAutor());

Android 
Examples

 

Observable.just(geocoder.getFromLocation(latLng.latitude, latLng.longitude))
        .observeOn(AndroidSchedulers.mainThread())
        .subscribeOn(Schedulers.newThread())
        .filter(addresses -> !addresses.isEmpty())
        .flatMap(Observable::from)
        .first()
        .subscribe(address -> {
            callback.addressFound(address);
        })