bustling-glacier-6043

readme.md

bustling-glacier-6043

Created with <3 with dartpad.dev.

main.dart

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

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

class MyApp extends StatelessWidget {
  const MyApp({Key? key}) : super(key: key);

  static const String _title = 'Flutter Code Sample';

  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: _title,
      home: Scaffold(
        appBar: AppBar(title: const Text(_title)),
        body: const MyStatefulWidget(),
      ),
    );
  }
}

class MyStatefulWidget extends StatefulWidget {
  const MyStatefulWidget({Key? key}) : super(key: key);

  @override
  State<MyStatefulWidget> createState() => _MyStatefulWidgetState();
}

class _MyStatefulWidgetState extends State<MyStatefulWidget> {
  final List<int> _items = List<int>.generate(50, (int index) => index);
  bool _dragStarted = false;
  bool _grabStarted = false;

  @override
  Widget build(BuildContext context) {
    final ColorScheme colorScheme = Theme.of(context).colorScheme;
    final Color oddItemColor = colorScheme.primary.withOpacity(0.05);
    final Color evenItemColor = colorScheme.primary.withOpacity(0.15);

    return ReorderableListView(
      proxyDecorator: (child, index, animation) => MouseRegion(
        cursor: SystemMouseCursors.grabbing,
        child: AnimatedBuilder(
          animation: animation,
          builder: (BuildContext context, Widget? child) {
            final double animValue =
                Curves.easeInOut.transform(animation.value);
            final double elevation = lerpDouble(0, 6, animValue)!;
            return Material(
              color: Colors.transparent,
              elevation: elevation,
              child: child,
            );
          },
        ),
      ),
      buildDefaultDragHandles: false,
      padding: const EdgeInsets.symmetric(horizontal: 40),
      children: [
        for (int index = 0; index < _items.length; index += 1)
          ColoredBox(
            color: _items[index].isOdd ? oddItemColor : evenItemColor,
            key: Key('$index'),
            child: Row(
              children: <Widget>[
                Container(
                  width: 64,
                  height: 64,
                  padding: const EdgeInsets.all(8),
                  child: ReorderableDragStartListener(
                    index: index,
                    child: MouseRegion(
                      cursor: _grabStarted
                          ? SystemMouseCursors.grabbing
                          : SystemMouseCursors.grab,
                      child: Card(
                        color: Theme.of(context).colorScheme.primary,
                        elevation: 2,
                      ),
                    ),
                  ),
                ),
                Text('Item ${_items[index]}'),
              ],
            ),
          ),
      ],
      onReorder: (int oldIndex, int newIndex) {
        setState(() {
          if (oldIndex < newIndex) {
            newIndex -= 1;
          }
          final int item = _items.removeAt(oldIndex);
          _items.insert(newIndex, item);
        });
      },
      onReorderStart: (index) {},
      onReorderEnd: (_) => setState(() => _grabStarted = false),
    );
  }
}