This is an example of how it could have been done previously in the ListView class, using the divider and dividerHeight parame
You can add with programaticly easily.
If your Layout Manager is Linearlayout then you can use:
DividerItemDecoration is a RecyclerView.ItemDecoration that can be used as a divider between items of a LinearLayoutManager. It supports both HORIZONTAL and VERTICAL orientations.
mDividerItemDecoration = new DividerItemDecoration(recyclerView.getContext(),
mLayoutManager.getOrientation());
recyclerView.addItemDecoration(mDividerItemDecoration);
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