如何在 notifyDataSetChanged 上禁用 recyclerview 滚动到顶部（第一项）

Question

I have fixed number of items in recycler view, but I update data every 10 seconds and calling notifyDataSetChanged();

When I scrolled to Nth item (EX:20th item) and on notifyDataSetChanged() called recycler view getting refreshed and auto-scroll back to 1st item. How can I stop scrolling and update the recycler view? Thanks in advance.

Answer 1

You can create a view type and holder for your first item then set setIsRecyclable

@Override
public void onBindViewHolder(final RecyclerView.ViewHolder holder, final int position) {
    if (holder instanceof HeaderViewHolder ) {
        ((HeaderViewHolder ) holder).setIsRecyclable(false);
        ((HeaderViewHolder ) holder).bind(mData.get(position));
    }
}

Answer 2

Using onSaveInstanceState you will save the state or current position of your recyclerview .Just like this.

Create veriable in your activity

Parcelable recylerViewList; //this will store the position

then create this method to fetch recyclerview state

void storeInstance() {
    AttachmentsActivity.recylerViewList=mRecyclerView?.layoutManager?.onSaveInstanceState()
}// call this method before notifyDataSetChanged()

Create method to restore the state

    void restore() //call this method after notifyDataSetChanged()
    {
     mRecyclerView?.layoutManager?.onRestoreInstanceState(recylerViewList)
    }

Make sure you have to call this methods in activity or through activity object .

Answer 3

You should find which items changed and use adapter.notifyItemChanged(itemChangedPosition) instead of notifyDatasetChanged()