Weird scrolling behaviour when use ScrollController + FutureBuilder + Provider + ListView.builder - flutter

Question

I created a list view based on a Future Provider. It works as expected.
Now I want to add a ScrollController in order to create a animated FloatingActionButton like Gmail "Compose" button.
I put controller attribute on listView.builder.
And here I have weird behaviour : I can't scroll. As soon as I scroll down or up listview is rebuilding and I can't perform any scroll.
Here my code :
ScrollController _scrollController = ScrollController();
bool isFAB = false;
#override
void initState() {
_scrollController.addListener(() {
if (_scrollController.offset > 50) {
setState(() {
isFAB = true;
});
} else {
setState(() {
isFAB = false;
});
}
});
super.initState();
}
#override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(
title: Text(AppLocalizations.of(context)!.toolListTitle),
),
body: FutureBuilder(
future:
Provider.of<MyTools>(context, listen: false).fetchAndSetTools(),
builder: (ctx, snapshot) => snapshot.connectionState ==
ConnectionState.waiting
? const Center(
child: CircularProgressIndicator(),
)
: Consumer<MyTools>(
child: Center(
child: Text(AppLocalizations.of(context)!.noToolYet),
),
builder: (ctx, myTools, ch) => myTools.items.isEmpty
? Center(
child: Text(AppLocalizations.of(context)!.noToolYet),
)
: ListView.builder(
controller: _scrollController,
scrollDirection: Axis.vertical,
itemCount: myTools.items.length,
itemBuilder: (ctx, i) => ToolWidget(
id: myTools.items[i].id,
name: myTools.items[i].name,
createdAt: myTools.items[i].createdAt,
description: myTools.items[i].description,
),
),
),
),
floatingActionButton: isFAB
? FloatingActionButton(
onPressed: () =>
Navigator.of(context).pushNamed(AddToolScreen.routeName),
child: Icon(
Icons.add_sharp,
color: Theme.of(context).primaryColor,
),
backgroundColor: Colors.black,
)
: FloatingActionButton.extended(
onPressed: () =>
Navigator.of(context).pushNamed(AddToolScreen.routeName),
icon: Icon(
Icons.add_sharp,
color: Theme.of(context).primaryColor,
),
backgroundColor: Colors.black,
label: Text(
"Add Tool",
style: TextStyle(
color: Theme.of(context).primaryColor,
),
),
));
}
}
Can you help me ?
Thanks

Answer 1

I think the
setState(() {
isFAB = true;
});
in your _scrollController.addListener function is resetting the scroll position to the top again.