Flutter - Reorderable ListView

ReorderableListView(
    {Key? key,
    required List<Widget> children,
    required ReorderCallback onReorder,
    void onReorderStart(
    int index
    )?,
    void onReorderEnd(
    int index
    )?,
    double? itemExtent,
    Widget? prototypeItem,
    ReorderItemProxyDecorator? proxyDecorator,
    bool buildDefaultDragHandles = true,
    EdgeInsets? padding,
    Widget? header,
    Widget? footer,
    Axis scrollDirection = Axis.vertical,
    bool reverse = false,
    ScrollController? scrollController,
    bool? primary,
    ScrollPhysics? physics,
    bool shrinkWrap = false,
    double anchor = 0.0,
    double? cacheExtent,
    DragStartBehavior dragStartBehavior = DragStartBehavior.start,
    ScrollViewKeyboardDismissBehavior keyboardDismissBehavior = ScrollViewKeyboardDismissBehavior.manual,
    String? restorationId,
    Clip clipBehavior = Clip.hardEdge}
)

import 'package:flutter/material.dart';

void main()
{
  runApp(ReorderLisst());
}
class ReorderLisst extends StatefulWidget {
 

  ReorderLisst({Key? key}) : super(key: key);
  @override
  _ReorderLisstState createState() => _ReorderLisstState();
}

class _ReorderLisstState extends State<ReorderLisst> {
  // list of items that are needed
  // to the reorderlistview widget.
  List<String> item = [
    "GeeksforGeeks",
    "Flutter",
    "Developer",
    "Android",
    "Programming",
    "CplusPlus",
    "Python",
    "javascript"
  ];
  
  // this method sort the item.
  void sorting() {
    setState(() {
    item.sort();
    });
  }
  
  // This method set the new index to the element.
  void reorderData(int oldindex, int newindex) {
    setState(() {
      if (newindex > oldindex) {
        newindex -= 1;
      }
      final items = item.removeAt(oldindex);
         item.insert(newindex, items);
    });
  }
  
  @override
  Widget build(BuildContext context) {
    // materialApp with 
    // debugShowCheckedModeBanner false and home
    return MaterialApp( 
      debugShowCheckedModeBanner: false,
      home: Scaffold(
      backgroundColor: Colors.green[400],
      // appbar with title
      appBar: AppBar( 
           title: Text(
          "Reorderable ListView",
         
        ),
       ),
      // This widget creates the 
      // reorderable list of item.
      body: ReorderableListView( 
        onReorder: reorderData,
        children: [
          for (final items in item)
            Card(
              color: Colors.white,
              key: ValueKey(items),
              elevation: 2,
              child: ListTitle(
                title: Text(items),
                
              ),
            ),
        ],
        ),
    )
    );
  }
}