ulises-codes/infinite_scroll_pagination

Flutter package to help you lazily load and display pages of items as the user scrolls down your screen.

Chosen as a Flutter Favorite by the Flutter Ecosystem Committee

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Infinite Scroll Pagination

Unopinionated, extensible and highly customizable package to help you lazily load and display small chunks of items as the user scrolls down the screen – known as infinite scrolling pagination, endless scrolling pagination, auto-pagination, lazy loading pagination, progressive loading pagination, etc.

Designed to feel like part of the Flutter framework.

Tutorial

By raywenderlich.com (step-by-step, hands-on, in-depth and illustrated).

Usage

class CharacterListView extends StatefulWidget {
  @override
  _CharacterListViewState createState() => _CharacterListViewState();
}

class _CharacterListViewState extends State<CharacterListView> {
  static const _pageSize = 20;

  final PagingController<int, CharacterSummary> _pagingController =
      PagingController(firstPageKey: 0);

  @override
  void initState() {
    _pagingController.addPageRequestListener((pageKey) {
      _fetchPage(pageKey);
    });
    super.initState();
  }

  Future<void> _fetchPage(int pageKey) async {
    try {
      final newItems = await RemoteApi.getCharacterList(pageKey, _pageSize);
      final isLastPage = newItems.length < _pageSize;
      if (isLastPage) {
        _pagingController.appendLastPage(newItems);
      } else {
        final nextPageKey = pageKey + newItems.length;
        _pagingController.appendPage(newItems, nextPageKey);
      }
    } catch (error) {
      _pagingController.error = error;
    }
  }

  @override
  Widget build(BuildContext context) => 
      // Don't worry about displaying progress or error indicators on screen; the 
      // package takes care of that. If you want to customize them, use the 
      // [PagedChildBuilderDelegate] properties.
      PagedListView<int, CharacterSummary>(
        pagingController: _pagingController,
        builderDelegate: PagedChildBuilderDelegate<CharacterSummary>(
          itemBuilder: (context, item, index) => CharacterListItem(
            character: item,
          ),
        ),
      );

  @override
  void dispose() {
    _pagingController.dispose();
    super.dispose();
  }
}

For more usage examples, please take a look at our cookbook or check out the example project.

Features

• Architecture-agnostic: Works with any state management approach, from setState to BLoC. Not even Future usage is assumed.

• Layout-agnostic: Out-of-the-box widgets corresponding to GridView, SliverGrid, ListView and SliverList – including .separated constructors. Not enough? You can easily create a custom layout.

• API-agnostic: By letting you in complete charge of your API calls, Infinite Scroll Pagination works with any pagination strategy.

• Highly customizable: You can change everything. Provide your own progress, error and empty list indicators. Too lazy to change? The defaults will cover you.

• Extensible: Seamless integration with pull-to-refresh, searching, filtering and sorting.

• Listen to state changes: In addition to displaying widgets to inform the current status, such as progress and error indicators, you can also use a listener to display dialogs/snackbars/toasts or execute any other action.

API Overview