How to implement Endless scrolling using StaggeredLayoutManager

Question

I already tried to implement the endless scrolling for LinearLayoutManager and it is successful and tried to copy the LinearLayoutManager implementation to StaggeredGridLayoutManager but it doesn't work.

I just want to get the firstVisibleItem.

in LinearLayoutManager :

int firstVisibleItem = linearLayoutManager.findFirstVisibleItemPosition(int);

but in StaggeredGridLayoutManager is :

int firstVisibleItem = staggeredGridLayoutManager.findFirstVisibleItemPositions(int[])

How to get the firstVisibleItem using (int) not (int[])?

Is there any good approach/implementation about this?

Thanks in advance.

Answer 1

I got it working:

You can use one of two methods in the StaggeredGridLayoutManager:

1. findFirstVisibleItemPositions(int[])
2. findFirstCompletelyVisibleItemPositions(int[])

Pass an empty int array that will get initialized with the positions and use the one that makes sense for you.

private boolean loading = true;
private int pastVisibleItems, visibleItemCount, totalItemCount;

mRecyclerView.setOnScrollListener(new RecyclerView.OnScrollListener({
        @Override
        public void onScrolled(RecyclerView recyclerView, int dx, int dy) {

        visibleItemCount = mLayoutManager.getChildCount();
        totalItemCount = mLayoutManager.getItemCount();
        int[] firstVisibleItems = null;
        firstVisibleItems = mLayoutManager.findFirstVisibleItemPositions(firstVisibleItems);
        if(firstVisibleItems != null && firstVisibleItems.length > 0) {
            pastVisibleItems = firstVisibleItems[0];
        }

        if (loading) {
            if ((visibleItemCount + pastVisibleItems) >= totalItemCount) {
                loading = false;
                Log.d("tag", "LOAD NEXT ITEM");
            }
        }
    }
});