How to remain at a scroll position in RecyclerView after adding items at its first index and call notifydatasetchange

Question

I am using a RecyclerView, I add items before the first item, the scroll position moves up to the newly first item added. How can I maintain my scroll position after adding new items at its first index and call notifydatasetchange() ?

this is what i do in my adapter

    mCurrentFragment.items.addAll(0, createLineItems(dataArrayList));

    notifyDataSetChanged();

Any suggestions ?

Ison

you can calculate it from the ammount of items you inserted and set scroll value manually – Prolocutor

Answer 1

There are two options:

1. Use the more sophisticated versions of notify

   List newData = createLineItems(dataArrayList);
   mCurrentFragment.items.addAll(0, newData);
   notifyItemRangeInserted(0, newData.size());
   

2. Use stable IDs. On your adapter override public long getItemId (int position) to make it return MEANINGFUL values and call setHasStableIds(true); on it.

Newmarket

@Newmarket What do you mean by MEANINGFUL? does it mean a unique id related to each item? – Calycle

@HamzehSoboh I meant exactly that. If your IDs are just the position (for example) it won't work. It must be (for example) the user ID, or the photo ID, so when the views position changes the ID remains bounded to the data – Newmarket

It worked on notifyItemRangeInserted but not setHasStableIds although getItemId was returning getTime() for that item's date, which is unique. – Calycle