How to prevent auto scroll in RecyclerView after notifyDataSetChanged?

问题

I have a RecyclerView with several items types. It looks like this:

07/21/2017
Message 1
Message 2
Message 3
07/22/2017
Message 4
New messages header
Message 5
Message 6

When new messages arrived I sort it by date and call notifyDataSetChanged(). It works well, but it automatically scroll my RecyclerView on new item(s) height. In this case I cannot use notifyItemInserted() because I don't know item position after sorting.

How to force RecyclerView do not scroll after notifyDataSetChanged() without call notifyItemInserted()?

回答1:

There are 4 ways you can try. Because I don't know what is the height of your view, so I can't sure if it really works. But let give it a try

I. You don't which specific item could be changed. But you know the range of that change

mAdapter.notifyItemInserted(position);                 
mAdapter.notifyItemRangeChanged(0, list.size());

II. Clear list before call notifyDataSetChanged()

yourList.clear();
mAdapter.notifyDataSetChanged();

III. Save/Reset state of ReyclerView before/after adding new item

    // Save state
    private Parcelable recyclerViewState;
    recyclerViewState = recyclerView.getLayoutManager().onSaveInstanceState();

    // Restore state
    recyclerView.getLayoutManager().onRestoreInstanceState(recyclerViewState);

IV. Use this function

mAdapter.notifyItemRangeChanged(0, list.size());

回答2:

Have you played with myRecView.getLayoutManager().setStackFromEnd(boolean) ?

If you can determine if the new item has been inserted after sorting above or below the visible part and in function of this call setStackFromEnd () with true or false maybe you can avoid the scroll.

I do not know if it will really work ....

回答3:

You can know where the new item has been inserted using list.indexOf(yourItem) on your list of items. Then you can call notifyItemInserted()

来源：https://stackoverflow.com/questions/45325621/how-to-prevent-auto-scroll-in-recyclerview-after-notifydatasetchanged

标签

android

android-recyclerview