Using StickyList.builder inside a NestedScrollView causes problems

[ndemari]

The issue is that the wrong number of items get built. The headers scroll up at the wrong time. And then i get an out of range exception. I changed the StickyList to a standard Listview and the problems went away.

The StickyList.builder is in a StreamBuilder and this is in a TabBarView. The TabBarView is apart of a NestedScrollView. Here is an example of my code...

Widget build(BuildContext context) {
  this.context = context;
  return Container(
    child: DefaultTabController(
      length: 3,
      child: NestedScrollView(
          headerSliverBuilder: (BuildContext context, bool innerBoxIsScrolled) {
            innerBoxIsScrolled = false;
            return <Widget>[
              SliverAppBar(
                expandedHeight: 125.0,
                floating: false,
                pinned: true,
                flexibleSpace: FlexibleSpaceBar(
                  centerTitle: true,
                  title: Text("${widget.locationName} Schedule",
                      style: TextStyle(
                        color: Colors.white,
                        fontSize: 16.0,
                      )),
                  background: Image.asset(
                    "assets/member-benefits.jpg",
                    fit: BoxFit.cover,
                    color: Color(0xff3e4b60),
                    colorBlendMode: BlendMode.hardLight,
                  ),
                ),
              ),
              SliverPersistentHeader(
                delegate: _SliverAppBarDelegate(
                  TabBar(
                    indicatorColor: Colors.black,
                    labelColor: Colors.white,
                    unselectedLabelColor: Colors.white30,
                    tabs: [
                      Tab(text: "BY DATE"),
                      Tab(text: "BY INSTRUCTOR"),
                      Tab(text: "BY CLASS"),
                    ],
                  ),
                ),
                pinned: true,
              )
            ];
          },
          body: TabBarView(
            children: <Widget>[
              StreamBuilder<QuerySnapshot>(
                stream: Firestore.instance
                    .collection("schedule")
                    .document(widget.locationName.toLowerCase())
                    .collection("by_date")
                    .orderBy("day")
                    .orderBy("time")
                    .snapshots(),
                builder: (BuildContext context, AsyncSnapshot<QuerySnapshot> snapshot) {
                  if (!snapshot.hasData) return Center(child: CircularProgressIndicator(),);

                  final int documentCount = snapshot.data.documents.length;
                  return Material(
                    child: StickyList.builder(
                      builder: (BuildContext context, int index) {
                        print(index);
                        final DocumentSnapshot doc = snapshot.data.documents[index];
                        final ListItem item = !doc.data.containsKey("className") ?
                        HeadingItem.fromSnapshot(doc) :
                        ScheduleItem.fromSnapshot(doc);

                        if (item is HeadingItem) {
                          HeaderRow header = HeaderRow(
                              child: Container(
                                  color: Colors.blue,
                                  child: Padding(
                                    padding: const EdgeInsets.all(10.0),
                                    child: Text(
                                      item.day.toString(),
                                      style: TextStyle(color: Colors.white, fontSize: 18.0),
                                    ),
                                  )
                              ),
                              height: 40.0
                          );
                          return header;
                        } else if (item is ScheduleItem) {
                          RegularRow row = RegularRow(
                              height: 20.0,
                              child: ListTile(
                                  leading: new CircleAvatar(
                                    child: new Text(item.time.toString()),
                                    radius: 27.0,
                                  ),
                                  title: new Text(item.className),
                                  subtitle: Text(item.leadBy)));
                          return row;
                        }
                      },
                      itemCount: documentCount,
                    ),
                  );
                },
              ),
              Material(child: buildByDateTab()),
              Material(child: buildByDateTab())
            ],
          )),
    ),
  );
}

[ndemari]

I think i've boiled it down to it now working at all (using the builder or the constructor) inside a StreamBuilder