Google's sample implementation of dividers displayed between the RecyclerView items

ItemDivider.java

@Override
    public void onDrawOver(Canvas c, RecyclerView parent,
                           RecyclerView.State state) {
        super.onDrawOver(c, parent, state);

        // calculate left/right x-coordinates for all dividers
        int left = parent.getPaddingLeft();
        int right = parent.getWidth() - parent.getPaddingRight();

        // for every item but the last, draw a line below it
        for (int i = 0; i < parent.getChildCount() - 1; ++i) {
            View item = parent.getChildAt(i); // get ith list item

            // calculate top/bottom y-coordinates for current divider
            int top = item.getBottom() + ((RecyclerView.LayoutParams)
                    item.getLayoutParams()).bottomMargin;
            int bottom = top + divider.getIntrinsicHeight();

            // draw the divider with the calculated bounds
            divider.setBounds(left, top, right, bottom);
            divider.draw(c);
        }
    }