Why PagedList adapter loading all data irrespective of pagesize?

Question

I have set the page size to 10, The page size in the observer is giving the right size, but all the items from the database(ROOM) is getting loaded to the view holder

The boundary call back onItemAtEndLoaded is getting called with the last item in the database.

Here is my configuration:

public LiveData<PagedList<Design>> getDesignList(List<String> types, String idCode){
    DataSource.Factory<Integer, Design> factory = mRepository.getDesigns(types, idCode);
    PagedList.Config pagedListConfig =
            (new PagedList.Config.Builder())
                    .setEnablePlaceholders(false)
                    .setInitialLoadSizeHint(10)
                    .setPageSize(10)
                    .build();
    return new LivePagedListBuilder<>(factory, pagedListConfig)
            .setBoundaryCallback(**boundCallBack**)
            .setFetchExecutor(mRepository.mIoExecutor)
            .build();
}

Repository(mRepository.getDesigns):

public DataSource.Factory<Integer, Design> getDesigns(List<String> types, String idCode) {
    return designDao.getDesigns(types,idCode);
}

Dao:(getDesigns)

@Query("SELECT * FROM Design WHERE design_type IN (:types) AND id=:idCode ORDER BY design_id ASC")
DataSource.Factory<Integer, Design> getDesigns(List<String> types, String idCode);

boundary callback(boundCallBack):

public class BoundCall extends PagedList.BoundaryCallback<Design> {
    public BoundCall() {
        super();
    }

    @Override
    public void onZeroItemsLoaded() {
        super.onZeroItemsLoaded();
        fetchFromNetwork(null);
        Log.e("load", "men-onZeroItemsLoaded");
    }

    @Override
    public void onItemAtFrontLoaded(@NonNull Design itemAtFront) {
        super.onItemAtFrontLoaded(itemAtFront);
        Log.e("load", "men-onItemAtFrontLoaded: " + itemAtFront.getDesignName());
    }

    @Override
    public void onItemAtEndLoaded(@NonNull Design itemAtEnd) {
        super.onItemAtEndLoaded(itemAtEnd);
        fetchFromNetwork(itemAtEnd);
        Log.e("load", "men-onItemAtEndLoaded: " + itemAtEnd.getDesignName());
    }
}

The observer:

designAdapter = new DesignAdapter(this);
    menClothRv.setAdapter(designAdapter);
    // Observer to the changed list in the
    obs = new Observer<PagedList<Design>>(){
        @Override
        public void onChanged(PagedList<Design> designs) { //the pagesize is 10 here, but all items are loaded
            if(!designs.isEmpty())
                designAdapter.submitList(designs);

        }
    };

Unable to figure it out: I even referred to this as well: pagedList loading

What the layout that your `RecyclerView` is included in? It sounds like your `RecyclerView` is within another scrolling view such as a `NestedScrollingView`, causing the `RecyclerView` to lay out all of its items. — ianhanniballake, Nov 07 '20 at 01:59
Yes, you are right. This got resolved by keeping recycler view out side the NestedScrollView. — Prafulla Nayak, Nov 07 '20 at 05:01

score 5 · Answer 1 · answered Nov 07 '20 at 05:39

It sounds like your RecyclerView is within another scrolling view such as a NestedScrollingView, causing the RecyclerView to lay out all of its items.

You should always avoid nesting containers that scroll in the same direction (i.e., both vertically) and instead separate the two, either using the header functionality built into Paging 3 or ConcatAdapter to build separate headers and footers that will scroll along with your other content.

Why PagedList adapter loading all data irrespective of pagesize?

1 Answers1