RxJava and Realm request make app skip frame

Question

I'm using RxJava and Realm database in an android project. But sometimes pressing a button is unresponsive and you have to do that many times for it to work sometime, and android log is saying xxx frame skipped. I know it has something to do with misusing UI thread. Here's some of my request, can someone tell me what's wrong with them? Realm wants me to perform IO request on the same thread I'm using the response(not too sure though).

public Flowable<List<ClothingItem>> getClothingItemsLocal() {
    return Flowable.just(dbProvider.getClothingItems(mSortType));
}

public Flowable<List<ClothingItem>> getClothingItemsRemote() {
    return clothingService.getAll("Bearer " + preferencesManager.getToken())
            .map(response -> response.items)
            .subscribeOn(Schedulers.io())
            .observeOn(AndroidSchedulers.mainThread())
            .doOnSuccess(clothingItems -> {
                dbProvider.clearClothingItems();
                dbProvider.saveOrUpdateClothingItems(clothingItems);
            })
            .toFlowable()
            .map(remoteItems -> dbProvider.getClothingItems(mSortType));
}

public Flowable<ClothingItem> getClothingItem(@NonNull final String id) {
    return getClothingItemRemote(id)
            .startWith(dbProvider.getClothingItem(id))
            .onErrorReturn(throwable -> dbProvider.getClothingItem(id));
}

getAll method with retrofit.

@GET(BuildConfig.BASE_API_PATH + "clothing_items")
Single<GetClothingItemsResponseModel> getAll(@Header("Authorization") String token);

Realm provider methods:

public void saveOrUpdateEvents(List<Event> data) {
    realmInstance.executeTransaction(realm -> {
        for (Event event : data) {
            if (!TextUtils.isEmpty(event.date)) {
                Date date = DateUtils.getFullDate(event.date);
                Timber.d("date %s", date.toString());
                event.timestamp = date;
            }
            Event cashedEvent = getEvent(event.id);
            if (cashedEvent.id != null) {
                event.eventClothingItems = cashedEvent.eventClothingItems;
                event.tags = cashedEvent.tags;
                event.location = cashedEvent.location;
            }
        }
        realm.delete(Event.class);
        realm.insertOrUpdate(data);
    });
}



public void clearClothingItems() {
    realmInstance.executeTransaction(realm -> {
        realm.delete(ClothingItem.class);
    });
}

IMHO I'd recommend you `.subscribeOn(Schedulers.io())` and `.observeOn(Schedulers.io())` before the `.map`. — grrigore, Mar 09 '20 at 13:50
I'd say before both of them, I am not an expert, but you could try that. — grrigore, Mar 09 '20 at 13:59
This is because your `dbProvider` does not take into account that Realm instances are thread-local, and so you are bound to the UI thread. But I'd have to modify the code in `dbProvider` to fix this issue. — EpicPandaForce, Mar 09 '20 at 15:41
Add the code for dbProvider.clearClothingItems(); dbProvider.saveOrUpdateClothingItems(clothingItems); and I'll tell you — EpicPandaForce, Mar 09 '20 at 18:42
What's wrong with these two methods please? dbProvider.clearClothingItems(); dbProvider.saveOrUpdateClothingItems(clothingItems); — Dr4ke the b4dass, Mar 10 '20 at 13:57

grrigore · Answer 1 · 2020-03-09T15:42:27.280

0

Try this:

public Flowable<List<ClothingItem>> getClothingItemsRemote() {
    return clothingService.getAll("Bearer " + preferencesManager.getToken())         
            .subscribeOn(Schedulers.io())   
            .map(response -> response.items) 
            .observeOn(AndroidSchedulers.mainThread())
            .doOnSuccess(clothingItems -> {
                dbProvider.clearClothingItems();
                dbProvider.saveOrUpdateClothingItems(clothingItems);
            })     
            .observeOn(Schedulers.computation())
            .toFlowable()
            .map(remoteItems -> dbProvider.getClothingItems(mSortType));
}

edited Mar 09 '20 at 15:42

answered Mar 09 '20 at 14:05

grrigore

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I'm having this error: `java.lang.IllegalStateException: Realm access from incorrect thread. Realm objects can only be accessed on the thread they were created.` – Dr4ke the b4dass Mar 09 '20 at 15:25
@Dr4ketheb4dass I've edited the answer, also can you add the code for `getAll()` method? – grrigore Mar 09 '20 at 15:28
I added the getAll() method, and made the changes, but I still have the same error – Dr4ke the b4dass Mar 09 '20 at 15:32
Where exactly do you get that error? Any line? Can you also share the realm related code? – grrigore Mar 09 '20 at 15:33
Realm objects can only be accessed on the thread they were created" – Dr4ke the b4dass Mar 09 '20 at 15:34
1

You need to open the Realm on the background thread to use it on the background thread (and then you must also strictly ensure that it is properly closed once you are done) – EpicPandaForce Mar 09 '20 at 15:41

RxJava and Realm request make app skip frame

1 Answers1