Flutter ListView Jumps To Top

Question

I am creating a news feed for my app and as I scroll down data is fetched from Firestore. As soon as I scroll up the listview literally snaps to the very top skipping all the other items in between. The listview works fine if I load it with static data but when i pull data from Firestore, the issue reemerges. I am not sure what's causing this behaviour.

Video demonstrating the irregular scrolling behaviour

Here is my code

return StreamBuilder(
            stream: Firestore.instance.collection(Constants.NEWS_FEED_NODE)
                .document("m9yyOjsPxV06BrxUtHdp").
            collection(Constants.POSTS_NODE).orderBy("timestamp",descending: true).snapshots(),
            builder: (BuildContext context, AsyncSnapshot snapshot) {
              if (!snapshot.hasData)
                return Center(child: CircularProgressIndicator(),);

              if (snapshot.data.documents.length == 0)
                return Container();
              //after getting the post ids, we then make a call to FireStore again
              //to retrieve the details of the individual posts
              return ListView.builder(
                  itemCount: snapshot.data.documents.length,
                  itemBuilder: (_, int index) {
                    return FeedItem2(feed: Feed.fireStore(
                        snapshot: snapshot.data.documents[index]),);
                  });
            },
          );

Answer 1

Solution of this problem.

ListView, and ScrollViews in general, tend to dispose of the children that are not currently visible on the screen. When we try to scroll back to the child, the child is reinitialized from scratch. But in this case, our child is a FutureBuilder; re-initializing it creates a progress indicator again just for a part of a second, then creates the page once again. This confuses the scrolling mechanism, throwing us around in non-deterministic ways.