adapter.kt

    private var ids = ArrayList<Long>()

    fun getIds(results : Any) : ArrayList<Long> {
        var ids = ArrayList<Long>()
        for (result in results) {
            ids.add(result.id)
        }
        return ids
    }

    init {
        hasStableIds();

        ids = getIds(results)
        results.onChange {

            val newIds = getIds(results)

            if (newIds.isEmpty()) {
                ids = newIds
                notifyDataSetChanged()
                return@onChange
            }

            val patch = DiffUtils.diff(ids, newIds)
            val deltas = patch.deltas
            ids = newIds

            if (!deltas.isEmpty()) {
                for (delta in deltas) {
                    if (delta.type == Delta.TYPE.INSERT) {
                        notifyItemRangeInserted(delta.revised.position, delta.revised.size())
                    } else if (delta.type == Delta.TYPE.DELETE) {
                        notifyItemRangeRemoved(delta.original.position, delta.original.size())
                    } else if (delta.type == Delta.TYPE.CHANGE) {
                        notifyItemRangeChanged(delta.revised.position, delta.revised.size())
                    } else {
                        notifyDataSetChanged()
                    }
                }
            }
        }
    }

    override fun getItemId(position : Int) : Long {
        return results[position].id
    }