Reactive Programming no Android

11
REACTIVE PROGRAMMING NO ANDROID
Guilherme Branco
Software Engineer
Guilherme Pereira Branco
@guipbranco

22
REACTIVE PROGRAMMING NO ANDROID
Guilherme Branco
Software Engineer
Guilherme Pereira Branco
@guipbranco

Reactive Programming
é do balacobaco!
Quem não usa está
por fora, meu!
Sou deveras
experiente em RxJava!

66
Reactive Programming | O Que é?
• Pull x Push: Ao invés de pedir algo e esperar, o desenvolvedor
simplesmente pede por algo e é notificado quando o resultado estiver
disponível.
• Paradigma baseado no conceito de fluxo de dados assíncrono.
• Mais flexível. O Desenvolvedor ignora se os dados chegam de forma
síncrona ou assíncrona. O código simplesmente funciona.
• Fontes de dados podem ser combinadas e não aninhadas, afastando o
desenvolvedor do “callback hell”

77
Observable Observer
Emite
item1
item2
item3
Manipula item 1
Manipula item 2
Manipula item 3
onNext(item1)
onNext(item2)
onNext(item3)
Itens acabaram onCompleted() completar
Ops! Erro… onError(error) Trata erro
Reactive Programming | Fluxo

99
Anatomia | Principal Construção
Observable.from(lectureService.getLectures()) 1. Observable
.subcribeOn(Schedulers.io()).observeOn(AndroidSchedulers.mainThread()) 3. Schedulers
.subscribe(getObserver()) 2. Observer

1010
public interface LectureService {
List<Lecture> getLectures();
}

1111

1212
Anatomia | Observer / Subscriber
private Observer<Lecture> getObserver(){
return new Observer<Lecture>() {
@Override
public void onCompleted() {
Log.e(TAG, "onCompleted");
}
@Override
public void onError(Throwable e) {
Log.e(TAG, "onError: " + e.getMessage());
}
@Override
public void onNext(Lecture lecture){
Log.e(TAG, "onNext");
}
});

1313
ObserverObservable
=
4. Subscription

1414
.subcribeOn(Schedulers.io()).observeOn(AndroidSchedulers.mainThread())
.subscribe(getObserver())
Observable<Lecture> observable = Observable.from(lectureService.getLectures()) ;
observableSubscription subscription =
1. subscription.unsubscribe()
2. CompositeSubscription compSubscription;
compSubscription.add(subscription);
3. compSubscription.unsubscribe()

1616
public interface LectureService {
List<Lecture> getLectures();
}
Exemplo | AsyncTask

1717
new LectureAsyncTask().execute();
private class LectureAsyncTask
extends AsyncTask<String, Void, List<Lecture>>{
@Override
protected void onPreExecute() {
showLoading();
}
@Override
protected List<Lecture> doInBackground(String... params){
return lectureService.getLectures();
}
@Override
protected void onPostExecute(List<Lecture> lectures){
hideLoading();
renderItems(lectures);
}
}
Anatomia | AsyncTask -> Reactive

1818
@Override
showLoading();
}
@Override
}
@Override
hideLoading();
}
}
Observable.from(lectureService.getLectures())
.doOnSubscribe(showLoading())
.subscribeOn(Schedulers.io())
.toList()

1919
.toList()

2020
@Override
showLoading();
}
@Override
}
@Override
hideLoading();
}
}
.subscribe(
new Subscriber<List<Lecture>>() {
@Override
hideLoading();
}
@Override
}
@Override
public void onNext(List<Lecture> lectures){
}
});
.toList()

2121
.subscribe(
@Override
hideLoading();
}
@Override
}
@Override
}
});

2222
@Override
showLoading();
}
@Override
}
@Override
hideLoading();
}
}
.subscribe(
@Override
hideLoading();
}
@Override
}
@Override
}
});
.toList()

2323
Exemplo | AsyncTask -> Reactive
android.view.ViewRootImpl$CalledFromWrongThreadException: Only the original thread that created a view hierarchy can touch its views.

2424
@Override
showLoading();
}
@Override
}
@Override
hideLoading();
}
}
.subscribe(
@Override
hideLoading();
}
@Override
}
@Override
}
});
.toList()

2525
.subscribe(
@Override
hideLoading();
}
@Override
}
@Override
}
});
.observeOn(AndroidSchedulers.mainThread())
.toList()

2626
Exemplo | RxJava
.subscribe(new Subscriber(){…});
.toList()

2828
.toList()
Exemplo | RxJava

2929
Operator | Filter
.filter(new Func1<Lecture, Boolean>() {
@Override
public Boolean call(Lecture lecture) {
return lecture.getDay().equalsIgnoreCase(day);
}
})
.toList()

3232
Observable<Lecture> observable = getLectures();
.map(new Func1<Lecture, String>() {
@Override
public String call(Lecture lecture) {
return lecture.getDay();
}
}) // Observable<String>
.cast(CharSequence.class) // Observable<CharSequence>
Operator | Map, Cast, Distinct…
.distinct() // Mesmo Observable sem dados repetidos
.toList() // Observable<List<CharSequence>>
observable

3333
Reactive Programming | Links
https://github.com/ReactiveX/RxJava
https://www.packtpub.com/application-development/rxjava-essentials
http://rxmarbles.com

34
http://github.com/gpbranco/rx-example-tdc

OBRIGADO.
Big Brains Wanted
Join our team! Go to arctouch.com/brjobs
Visit our booth to win an Apple Watch.

Reactive Programming no Android

Recommended

More Related Content

What's hot (18)

Viewers also liked (20)

Similar to Reactive Programming no Android (20)

Recently uploaded (20)

Reactive Programming no Android

Editor's Notes