How to add dividers and spaces between items in RecyclerView?

Question

This is an example of how it could have been done previously in the ListView class, using the divider and dividerHeight parame

Answer 1

For those who are looking just for spaces between items in the RecyclerView see my approach where you get equal spaces between all items, except in first and last items where I gave a bigger padding. I only apply padding to left/right in horizontal LayoutManager and to top/bottom in vertical LayoutManager.

public class PaddingItemDecoration extends RecyclerView.ItemDecoration {

    private int mPaddingPx;
    private int mPaddingEdgesPx;

    public PaddingItemDecoration(Activity activity) {
        final Resources resources = activity.getResources();
        mPaddingPx = (int) resources.getDimension(R.dimen.paddingItemDecorationDefault);
        mPaddingEdgesPx = (int) resources.getDimension(R.dimen.paddingItemDecorationEdge);
    }

    @Override
    public void getItemOffsets(Rect outRect, View view, RecyclerView parent, RecyclerView.State state) {
        super.getItemOffsets(outRect, view, parent, state);

        final int itemPosition = parent.getChildAdapterPosition(view);
        if (itemPosition == RecyclerView.NO_POSITION) {
            return;
        }
        int orientation = getOrientation(parent);
        final int itemCount = state.getItemCount();

        int left = 0;
        int top = 0;
        int right = 0;
        int bottom = 0;

        /** HORIZONTAL */
        if (orientation == LinearLayoutManager.HORIZONTAL) {
            /** all positions */
            left = mPaddingPx;
            right = mPaddingPx;

            /** first position */
            if (itemPosition == 0) {
                left += mPaddingEdgesPx;
            }
            /** last position */
            else if (itemCount > 0 && itemPosition == itemCount - 1) {
                right += mPaddingEdgesPx;
            }
        }
        /** VERTICAL */
        else {
            /** all positions */
            top = mPaddingPx;
            bottom = mPaddingPx;

            /** first position */
            if (itemPosition == 0) {
                top += mPaddingEdgesPx;
            }
            /** last position */
            else if (itemCount > 0 && itemPosition == itemCount - 1) {
                bottom += mPaddingEdgesPx;
            }
        }

        if (!isReverseLayout(parent)) {
            outRect.set(left, top, right, bottom);
        } else {
            outRect.set(right, bottom, left, top);
        }
    }

    private boolean isReverseLayout(RecyclerView parent) {
        if (parent.getLayoutManager() instanceof LinearLayoutManager) {
            LinearLayoutManager layoutManager = (LinearLayoutManager) parent.getLayoutManager();
            return layoutManager.getReverseLayout();
        } else {
            throw new IllegalStateException("PaddingItemDecoration can only be used with a LinearLayoutManager.");
        }
    }

    private int getOrientation(RecyclerView parent) {
        if (parent.getLayoutManager() instanceof LinearLayoutManager) {
            LinearLayoutManager layoutManager = (LinearLayoutManager) parent.getLayoutManager();
            return layoutManager.getOrientation();
        } else {
            throw new IllegalStateException("PaddingItemDecoration can only be used with a LinearLayoutManager.");
        }
    }
}

dimens.xml

    10dp
    20dp