DeliverLatestCache & RecyclerView Restoring State Question about nucleus HOT 6 CLOSED

Hi,

The idea is that data normally gets updated on some internal event (pull to refresh, synchronization, etc). So the data-to-view pipeline should be reusable and there should be no difference between sending data once, twice, on each resume, on each recreation, etc.

I may probably change this behaviour in next versions, but I see no reason for doing this. Saving a couple of ms during onResume will come at the cost of slightly increased complexity. When there is no clear advantage I prefer simpler solutions.

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About your use case. Why don't you want to update adapter on resume? Why do you need to recreate it?

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In that scenario, it was a non-paging list so it didn't matter if i recreated it. But I guess it is better practice to save a reference to the adapter rather than recreate it every time.

To follow up on the paging, I had a question regarding deliverReplay(). In you paging example, you use restartableReplay to spit back the fetched Items to the view. From you documentation it says that this "keeps all onNext values and emits them each time a new view gets attached." I just wanted to clarify on this. Does it emit all items only when a view is attached and otherwise just emits the most recently fetched?

EDIT: for those seeing this at a later date, the answer is yes, it emit all items only when a view is attached and otherwise just emits the most recently fetched.

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The idea is that data normally gets updated on some internal event (pull to refresh, synchronization, etc).

@konmik How would you go about implementing this (pull-to-refresh, etc.) for something like a Retrofit service Observable? I have approximately the following in my RxPresenter:

public void fetchData(String someInput) {
    final Observable<List<Thing>> getThings = service.getStuff(someInput);

    restartableLatestCache(RESTARTABLE_THINGS,
            () -> getThings
                    .subscribeOn(Schedulers.io())
                    .observeOn(AndroidSchedulers.mainThread()),
            ThingsActivity::onNewData,
            ThingsActivity::onError);

    start(RESTARTABLE_THINGS);
}

This is called manually by the user from the view (as it requires user input). As it stands, it works great and caches the data so it doesn't repeat network queries on configuration change, etc. as expected. But what if I wanted to add swipe-to-refresh? How would I "invalidate the cache" here?

Thanks!

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the only place where restartableLatestCache have meaning is onCreate

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Oh, I see - I misunderstood restartableLatestCache (and friends). Thanks.

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