main.dart

import 'dart:async';

import 'package:flutter/material.dart';
import 'package:liquid_pull_to_refresh/liquid_pull_to_refresh.dart';

main() => runApp(MyApp());

class MyApp extends StatefulWidget {
  @override
  State<StatefulWidget> createState() {
    return _MyApp();
  }
}

class _MyApp extends State<MyApp> {
// Here is your list items.
  static final List<String> _items = <String>[
    'A',
    'B',
    'C',
    'D',
    'E',
    'F',
    'G',
    'H',
    'I',
    'J',
    'K',
    'L',
    'M',
    'N'
  ];

  // Refresh key!
  final GlobalKey<RefreshIndicatorState> _refreshIndicatorKey =
      GlobalKey<RefreshIndicatorState>();

  // Scaffold key!
  final GlobalKey<ScaffoldState> _scaffoldKey = GlobalKey<ScaffoldState>();

  // You can put any thing you like, like refetching posts or data from internet
  Future<void> _handleRefresh() {
    final Completer<void> completer = Completer<void>();

    Timer(const Duration(seconds: 3), () {
      completer.complete();
    });

    return completer.future.then<void>((_) {
      _scaffoldKey.currentState?.showSnackBar(SnackBar(
          content: const Text('Refresh complete'),
          action: SnackBarAction(
              label: 'RETRY',
              onPressed: () {
                _refreshIndicatorKey.currentState.show();
              })));
    });
  }

  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      home: Scaffold(
        appBar: AppBar(
          title: Text("L2P App"),
        ),
        body: LiquidPullToRefresh(
          key: _refreshIndicatorKey,
          onRefresh: _handleRefresh,
          showChildOpacityTransition: true,
          child: ListView.builder(
            padding: kMaterialListPadding,
            itemCount: _items.length,
            itemBuilder: (BuildContext context, int index) {
              final String item = _items[index];
              return ListTile(
                isThreeLine: true,
                leading: CircleAvatar(child: Text(item)),
                title: Text('This item represents $item.'),
                subtitle: const Text(
                    'Even more additional list item information appears on line three.'),
              );
            },
          ),
        ),
      ),
    );
  }
}

pubspec.yaml

name: lp2app
description: A new Flutter project.

# The following defines the version and build number for your application.
# A version number is three numbers separated by dots, like 1.2.43
# followed by an optional build number separated by a +.
# Both the version and the builder number may be overridden in flutter
# build by specifying --build-name and --build-number, respectively.
# In Android, build-name is used as versionName while build-number used as versionCode.
# Read more about Android versioning at https://developer.android.com/studio/publish/versioning
# In iOS, build-name is used as CFBundleShortVersionString while build-number used as CFBundleVersion.
# Read more about iOS versioning at
# https://developer.apple.com/library/archive/documentation/General/Reference/InfoPlistKeyReference/Articles/CoreFoundationKeys.html
version: 1.0.0+1

environment:
  sdk: ">=2.1.0 <3.0.0"

dependencies:
  flutter:
    sdk: flutter

  # The following adds the Cupertino Icons font to your application.
  # Use with the CupertinoIcons class for iOS style icons.
  cupertino_icons: ^0.1.2
  liquid_pull_to_refresh: ^1.1.1

dev_dependencies:
  flutter_test:
    sdk: flutter


# For information on the generic Dart part of this file, see the
# following page: https://dart.dev/tools/pub/pubspec

# The following section is specific to Flutter.
flutter:

  # The following line ensures that the Material Icons font is
  # included with your application, so that you can use the icons in
  # the material Icons class.
  uses-material-design: true

  # To add assets to your application, add an assets section, like this:
  # assets:
  #  - images/a_dot_burr.jpeg
  #  - images/a_dot_ham.jpeg

  # An image asset can refer to one or more resolution-specific "variants", see
  # https://flutter.dev/assets-and-images/#resolution-aware.

  # For details regarding adding assets from package dependencies, see
  # https://flutter.dev/assets-and-images/#from-packages

  # To add custom fonts to your application, add a fonts section here,
  # in this "flutter" section. Each entry in this list should have a
  # "family" key with the font family name, and a "fonts" key with a
  # list giving the asset and other descriptors for the font. For
  # example:
  # fonts:
  #   - family: Schyler
  #     fonts:
  #       - asset: fonts/Schyler-Regular.ttf
  #       - asset: fonts/Schyler-Italic.ttf
  #         style: italic
  #   - family: Trajan Pro
  #     fonts:
  #       - asset: fonts/TrajanPro.ttf
  #       - asset: fonts/TrajanPro_Bold.ttf
  #         weight: 700
  #
  # For details regarding fonts from package dependencies,
  # see https://flutter.dev/custom-fonts/#from-packages