Current scroll offset inside a Flutter ListView, SliverList,etc

Question

How do I get the current scroll offset inside a Flutter ListView, GridView, SliverList`, etc?

Answer 1

• If you're inside the scroll view use Scrollable.of(context).position.pixels.
• If you're outside, you probably want to hand a ScrollController in as the controller argument of the scroll view, then you can read controller.offset.
• Alternatively, use scroll notifications with NotificationListener.

This was asked on Flutter Gitter, and answered: https://gitter.im/flutter/flutter?at=591243f18a05641b1167be0e

Answer 2

For someone else, looking for code implementation, you can use ScrollController like this:

• Using NotificationListener:

  NotificationListener<ScrollNotification>(
    onNotification: (scrollNotification) {
      print(scrollNotification.metrics.pixels); // <-- This is it.
      return false;
    },
    child: ListView.builder(
      itemCount: 200,
      itemBuilder: (c, i) => Text('Item $i'),
    ),
  )
  

• Using ScrollController.offset

  final ScrollController _controller = ScrollController();
  
  @override
  void initState() {
    super.initState();
    _controller.addListener(() {
      print(_controller.offset); // <-- This is it.
    });
  }
  
  @override
  void dispose() {
    _controller.dispose();
    super.dispose();
  }
  
  @override
  Widget build(BuildContext context) {
    return Scaffold(
      body: ListView.builder(
        controller: _controller,
        itemCount: 200,
        itemBuilder: (c, i) => Text('Item $i'),
      ),
    );
  }