movefunction.kt

   override fun onMove(recyclerView: RecyclerView,
                                viewHolder: RecyclerView.ViewHolder,
                                target: RecyclerView.ViewHolder): Boolean {
                val adapter = recyclerView.adapter as MoviesAdapter
                val from = viewHolder.adapterPosition
                val to = target.adapterPosition
                adapter.moveItemInRecyclerViewList(from, to)
                adapter.notifyItemMoved(from, to)

                return true
            } 

fun moveItemInRecyclerViewList(from: Int, to: Int) {

        val list = differ.currentList.toMutableList()
        val fromLocation = list[from]
        list.removeAt(from)
        if (to < from) {
          //+1 because it start from 0 on the upside. otherwise it will not change the locations accordingly
            list.add(to + 1 , fromLocation)
        } else {
           //-1 because it start from length + 1 on the down side. otherwise it will not change the locations accordingly
           list.add(to - 1, fromLocation)
        }
        differ.submitList(list)
    }