Recycler view not scrolling to the top after adding new item at the top, as changes to the list adapter has not yet occurred

Question

I am getting the new list with new item at the start in my live data and then using its data to update the adapter

viewModel.myLiveData.observe { this, Observer { myList ->          adapter.submitList(myList)          recyclerView.scrollToPosition(0) } 

Answer 1

submitList does its work on a background thread, so there will always be race conditions that delays can't solve. Fortunately, we can use a RecyclerView.AdapterDataObserver callback to be informed when the list calculations are complete:

yourRecyclerViewAdapter.registerAdapterDataObserver(object: RecyclerView.AdapterDataObserver() {     override fun onChanged() {         recycler_view_list.scrollToPosition(0)     }     override fun onItemRangeRemoved(positionStart: Int, itemCount: Int) {         recycler_view_list.scrollToPosition(0)     }     override fun onItemRangeMoved(fromPosition: Int, toPosition: Int, itemCount: Int) {         recycler_view_list.scrollToPosition(0)     }     override fun onItemRangeInserted(positionStart: Int, itemCount: Int) {         recycler_view_list.scrollToPosition(0)     }     override fun onItemRangeChanged(positionStart: Int, itemCount: Int) {         recycler_view_list.scrollToPosition(0)     }     override fun onItemRangeChanged(positionStart: Int, itemCount: Int, payload: Any?) {         recycler_view_list.scrollToPosition(0)     } })  viewModel.myLiveData.observe { this, Observer { myList ->          adapter.submitList(myList)  }