SpacesItemDecoration.kt

class SpacesItemDecoration(val outerOffset: Int,
                           val innerOffset: Int,
                           val orientationType: OrientationType = VERTICAL) : RecyclerView.ItemDecoration() {

    enum class OrientationType {
        VERTICAL, HORIZON
    }

    override fun getItemOffsets(outRect: Rect, view: View, parent: RecyclerView,
                                state: RecyclerView.State) {
        if (orientationType == VERTICAL) {
            if (parent.childCount == 1) {
                outRect.top = outerOffset
                outRect.bottom = innerOffset
            } else if (parent.getChildAdapterPosition(view) == state.itemCount - 1) {
                outRect.top = 0
                outRect.bottom = outerOffset
            } else if (parent.getChildAdapterPosition(view) == 0) {
                outRect.top = outerOffset
                outRect.bottom = innerOffset
            } else {
                outRect.bottom = innerOffset
            }
        } else {
            if (parent.childCount == 1) {
                outRect.left = outerOffset
                outRect.right = innerOffset
            } else if (parent.getChildAdapterPosition(view) == state.itemCount - 1) {
                outRect.right = outerOffset
                outRect.left = 0
            } else if (parent.getChildAdapterPosition(view) == 0) {
                outRect.left = outerOffset
                outRect.right = innerOffset
            } else {
                outRect.right = innerOffset
            }
        }
    }
}