Reputation: 2395
I am using RxJava 2 in my Android application, and am integrating Realm. As far as I can tell, Realm only supports RxJava 1 by default, and allows an Observable
to be returned when querying for RealmResults<?>
, like so:
Realm.getDefaultInstance()
.where(VideoBundle.class)
.findAll()
.asObservable()
.first()
The Observable returned is from RxJava 1. How can I use Realm and RxJava 2 together? I have come across 2 relevant issues, found here and here, but no succinct answer was found. Additionally, the documentation (found here: https://realm.io/docs/java/latest/#rxjava) mentions creating a custom RxObservableFactory
, but provides no resources on how to do so.
How can Realm be used with a project already using RxJava 2?
Upvotes: 2
Views: 4973
Reputation: 81588
The solution is to wrap RealmResults with Flowable, with LATEST backpressure strategy.
private io.reactivex.Flowable<RealmResults<_>> getSomeItems() {
return io.reactivex.Flowable.create(new FlowableOnSubscribe<RealmResults<__>>() {
@Override
public void subscribe(FlowableEmitter<RealmResults<__>> emitter)
throws Exception {
Realm realm = Realm.getDefaultInstance();
RealmResults<__> results = realm.where(__.class).findAllSortedAsync("__");
final RealmChangeListener<RealmResults<__>> listener = _realm -> {
if(!emitter.isUnsubscribed() && results.isLoaded()) {
emitter.onNext(results);
}
};
emitter.setDisposable(Disposables.fromRunnable(() -> {
results.removeChangeListener(listener);
realm.close();
}));
results.addChangeListener(listener);
}
}, BackpressureStrategy.LATEST)
.subscribeOn(AndroidSchedulers.mainThread())
.unsubscribeOn(AndroidSchedulers.mainThread());
From Realm 4.0.0-RC1 and above, this behavior I showed above is baked in using realmResults.asFlowable()
.
Disposable subscription = realm.where(__.class)
.findAllSortedAsync("__")
.asFlowable()
.filter(RealmResults::isLoaded)
.subscribe(...);
Upvotes: 3