nested_scroll_view_plus

An enhanced NestedScrollView with support for overscrolling for both the inner and outer scrollviews.

🔥 Preview

Try it online: https://flutter-nested-scroll-view-plus.vercel.app

đź’ˇ Usage

Installation:

flutter pub add nested_scroll_view_plus

Example usage:

  1. Wrap your SliverAppBar with OverlapAbsorberPlus
  2. Use OverlapInjectorPlus on top of your inner CustomScrollView
  3. Change the physics of CustomScrollView to AlwaysScrollableScrollPhysics

That’s it!

import 'package:nested_scroll_view_plus/nested_scroll_view_plus.dart';

NestedScrollViewPlus(
  headerSliverBuilder: (context, innerScrolled) => <Widget>[
    // 1. Wrap your SliverAppBar with OverlapAbsorberPlus
    OverlapAbsorberPlus(
      sliver: SliverAppBar(), // Your SliverAppBar
    ),
  ],
  body: TabBarView(
    children: [
      CustomScrollView(
        // 2. [IMPORTANT] Change the physics of CustomScrollView to AlwaysScrollableScrollPhysics
        physics: const BouncingScrollPhysics(
          parent: AlwaysScrollableScrollPhysics(),
        ),
        slivers: <Widget>[
          // 3. Use OverlapInjectorPlus on top of your inner CustomScrollView
          OverlapInjectorPlus(),
          // Other children of CustomScrollView
          // ...,
        ],
      ),
    ],
  ),
);

For additional examples, please visit the scroll_master repository. It includes features such as pull-to-refresh for NestedScrollView, combined scrolling for scrollview and tabview, and more.

đź“’ Others

⚙️ Accessing the Inner or Outer Scroll Controller

To access the inner or outer scroll controller of a NestedScrollViewPlus, you can use a GlobalKey<NestedScrollViewStatePlus> to get its state.

class _ExampleState extends State<Example> {
  // 1. Create a GlobalKey
  final GlobalKey<NestedScrollViewStatePlus> myKey = GlobalKey();

  @override
  Widget build(BuildContext context) {
    return NestedScrollViewPlus(
      // 2. Set the key to NestedScrollViewStatePlus
      key: myKey,
      // ...,
    );
  }

  @override
  void initState() {
    super.initState();
    WidgetsBinding.instance.addPostFrameCallback((timeStamp) {
      // 3. Access the inner or outer scroll controller using GlobalKey<NestedScrollViewStatePlus>
      myKey.currentState!.innerController.addListener(_handleInnerScroll);
      myKey.currentState!.outerController.addListener(_handleOuterScroll);
    });
  }

  void _handleInnerScroll() {
    final innerController = myKey.currentState!.innerController;
    if (innerController.positions.length == 1) {
      print('Scrolling inner nested scrollview: ${innerController.offset}');
    }
  }

  void _handleOuterScroll() {
    final outerController = myKey.currentState!.outerController;
    if (outerController.positions.length == 1) {
      print('Scrolling outer nested scrollview: ${outerController.offset}');
    }
  }
}

đźš© Preserve Scroll Positions of Inner CustomScrollViews

To preserve the scroll positions of inner CustomScrollViews, you can add a PageStorageKey to the CustomScrollView widget. Here’s an example:

CustomScrollView(
  key: PageStorageKey<String>('unique-key'),
  slivers: <Widget>[
    // ...,
  ],
),

By assigning a unique key to the CustomScrollView, Flutter’s PageStorage mechanism will store and restore the scroll position of the inner CustomScrollViews, allowing you to maintain the scroll positions even when the widget tree is rebuilt.

⭕️ For Older Flutter Versions

If you are using an older version of Flutter, please follow these steps to install the appropriate branch from the old git repository.

dependencies:
  custom_nested_scroll_view:
    git:
      url: https://github.com/idootop/custom_nested_scroll_view.git
      # Choose the branch based on your local Flutter version
      ref: flutter-3.7

The different branches support the following Flutter versions:

Git branch Supported flutter versions
flutter-3.7 >=3.7.0-13.0.pre
flutter-3.4 >=3.4.0-27.0.pre <3.7.0-13.0.pre
flutter-3.4-pre >=3.4.0-17.0.pre <3.4.0-27.0.pre
flutter-3.0 >=2.12.0-4.0.pre <3.4.0-17.0.pre
flutter-2.x <2.12.0-4.0.pre

GitHub

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