@Override
public void onLayoutChildren(RecyclerView.Recycler recycler, RecyclerView.State state) {
super.onLayoutChildren(recycler, state);
cacheHeaderPositions();
positioner.reset(getOrientation(), findFirstVisibleItemPosition());
positioner.updateHeaderState(
findFirstVisibleItemPosition(), getVisibleHeaders(), viewRetriever.setRecycler(recycler));
}
@Override
public int scrollVerticallyBy(int dy, RecyclerView.Recycler recycler, RecyclerView.State state) {
int scroll = super.scrollVerticallyBy(dy, recycler, state);
if (Math.abs(scroll) > 0) {
positioner.updateHeaderState(
findFirstVisibleItemPosition(), getVisibleHeaders(), viewRetriever.setRecycler(recycler));
}
return scroll;
}