Using Realm with RxJava

Using Realm with RxJava

Transcript

1. Using Realm with RxJava Wasabeef
2. About Me wasabeef CyberAgent, Inc.
3. Realm Latest v0.80.1 (2015.4.23)
4. Introduction
5. Realm
6. Realm.getInstance() Realm realm = Realm.getInstance(this);
7. RealmObject public class User extends RealmObject { /** Other fields… **/ }
8. RealmList<T> public class User extends RealmObject { private RealmList<Email> emails; /** Other fields… **/ }
9. RealmQuery<T> RealmQuery<User> query = realm.where(User.class); query.equalTo(“name”, “Wasabeef”);
10. RealmResults<T> RealmResults<User> result = query.findAll();
11. RxJava
12. Observable<T> String[] names = {“Wasabeef”, “Chip”}; ! Observable.from(names).subscribe(s -> { Log.d(“Hello ” + s); });
13. map, flatMap… etc. Observable.from(names) .subscribeOn(Schedulers.newThread()) .map(new Func1<String, String>() { @Override public String call(String name) { return name.toUpperCase(); } }) .observeOn(AndroidSchedulers.mainThread()) .subscribe(s -> { Log.d(“Hello ” + s); });
14. subscribe(onNext, onError..) Observable.from(names).subscribe( new Observer<String>() { @Override public void onCompleted() { } ! @Override public void onError(Throwable e) { } ! @Override public void onNext(String s) { } });
15. Wrapping Realm around RxJava Source: http://kboyarshinov.com/android/wrapping-realm-around-rxjava/
16. issues #865
17. issue #865 ! // Get observable of all users Realm.getInstance(context) .where(User.class) .findAll() .observable() .subscribe(users -> { // do stuff with users });
18. Defining Realm model public class RealmUser extends RealmObject { private String name; ! public String getName() { return name; } ! public void setName(String name) { this.name = name; } }
19. Defining Immutable POJO public class User { private String name; ! public User(String name) { this.name = name; } ! public String getName() { return name; } }
20. Observing Realm
21. public abstract class OnSubscribeRealm<T extends RealmObject> implements Observable.OnSubscribe<T> { ! /** constructor **/ ! @Override public void call(final Subscriber<? super T> subscriber) { Realm realm = Realm.getInstance(context); subscriber.add(Subscriptions.create(() -> { try { realm.close(); } catch (RealmException ex) { subscriber.onError(ex); } })); ! T object; realm.beginTransaction(); try { object = get(realm); realm.commitTransaction(); } catch (RuntimeException e) { realm.cancelTransaction(); subscriber.onError(new RealmException(Error during transaction., e)); return; } catch (Error e) { realm.cancelTransaction(); subscriber.onError(e); return; } if (object != null) { subscriber.onNext(object); } subscriber.onCompleted(); } ! public abstract T get(Realm realm); }
22. public final class RealmObservable { ! private RealmObservable() { } ! public static <T extends RealmObject> Observable<T> object( Context context, Func1<Realm, T> function) { ! return Observable.create(new OnSubscribeRealm<T>(context) { @Override public T get(Realm realm) { return function.call(realm); } }); } }
23. public class RealmDataService { private Context context; ! public RealmDataService(Context context) { this.context = context.getApplicationContext(); } ! public Observable<User> addUser(String userName) { return RealmObservable.object(context, new Func1<Realm, RealmUser>() { @Override public RealmUser call(Realm realm) { RealmUser realmUser = new RealmUser(); realmUser.setName(userName); return realm.copyToRealm(realmUser); } }).map(new Func1<RealmUser, User>() { @Override public User call(RealmUser realmUser) { // map to UI object return new User(realmUser.getName()); } }); } } Data Service
24. Usage private void addUser() { Subscription subscription = dataService.addUser(“Wasabeef”) .subscribeOn(Schedulers.io()) .observeOn(AndroidSchedulers.mainThread()) .subscribe( user -> /** use user data **/, throwable -> /** error! **/ ); if (compositeSubscription != null) { compositeSubscription.add(subscription); } }
25. Wasabeef
26. CyberAgent, Inc.
27. Thanks.