The [DividerItemDecoration](<https://developer.android.com/reference/android/support/v7/widget/DividerItemDecoration.html>) is a RecyclerView.ItemDecoration that can be used as a divider between items.

DividerItemDecoration mDividerItemDecoration = new DividerItemDecoration(context,
             mLayoutManager.getOrientation());
recyclerView.addItemDecoration(mDividerItemDecoration);

It supports both orientation using DividerItemDecoration.VERTICAL and DividerItemDecoration.HORIZONTAL.