How to use proxyDecorator like in flutter's ReorderableListView

Sure you can! Here's an example:
import 'package:flutter/material.dart';
import 'package:great_list_view/great_list_view.dart';

void main() {
  Executor().warmUp();
  runApp(App());
}

class App extends StatefulWidget {
  @override
  _AppState createState() => _AppState();
}

class _AppState extends State<App> {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
        title: 'Test App',
        home: SafeArea(
            child: Scaffold(
          body: Body(key: gkey),
        )));
  }
}

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

  @override
  _BodyState createState() => _BodyState();
}

class _BodyState extends State<Body> {
  late List<Item> currentList;

  @override
  void initState() {
    super.initState();
    currentList = listA;
  }

  void swapList() {
    setState(() {
      if (currentList == listA) {
        currentList = listB;
      } else {
        currentList = listA;
      }
    });
  }

  @override
  Widget build(BuildContext context) {
    return Scrollbar(
      child: AutomaticAnimatedListView<Item>(
        addAnimatedElevation: 0.0, // we want to use a custom Material
        list: currentList,
        comparator: AnimatedListDiffListComparator<Item>(
            sameItem: (a, b) => a.id == b.id,
            sameContent: (a, b) => a.color == b.color),
        itemBuilder: (context, item, data) => item.build(context, data),
        listController: controller,
        reorderModel: AutomaticAnimatedListReorderModel(currentList),
        detectMoves: true,
      ),
    );
  }
}

class Item {
  final int id;
  final Color color;
  final double? fixedHeight;
  const Item(this.id, [this.color = Colors.blue, this.fixedHeight]);

  Widget build(BuildContext context, AnimatedWidgetBuilderData data) {
    return data.measuring
        ? Container(
            margin: EdgeInsets.all(5),
            padding: EdgeInsets.all(15),
            child: const Center(
              child: Text(
                'Item 999',
                style: TextStyle(fontSize: 16),
              ),
            ),
          )
        : Material(
            elevation: data.dragging ? 10 : 0,
            shadowColor: Colors.red,
            borderRadius: BorderRadius.all(Radius.circular(20)),
            child: GestureDetector(
              onTap: () => gkey.currentState?.swapList(),
              child: AnimatedContainer(
                duration: const Duration(milliseconds: 500),
                margin: EdgeInsets.all(5),
                padding: EdgeInsets.all(15),
                decoration: BoxDecoration(
                  color: color,
                  border: Border.all(color: Colors.black12, width: 0),
                  borderRadius: BorderRadius.all(Radius.circular(20)),
                ),
                child: Center(
                  child: Text(
                    'Item $id',
                    style: TextStyle(fontSize: 16),
                  ),
                ),
              ),
            ),
          );
  }
}

List<Item> listA = [
  Item(1, Colors.orange),
  Item(2),
  Item(3),
  Item(4, Colors.cyan),
  Item(5),
  Item(8, Colors.green)
];
List<Item> listB = [
  Item(4, Colors.cyan),
  Item(2),
  Item(6),
  Item(5, Colors.pink, 100),
  Item(7),
  Item(8, Colors.yellowAccent),
];

final controller = AnimatedListController();
final gkey = GlobalKey<_BodyState>();
DavideBelsole / great_list_view

How to use proxyDecorator like in flutter's ReorderableListView #27
