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Я хочу DraggableScrollableSheet , чтобы он начал сворачиваться, когда внутренний список (тот, что внутри ItCrowdPage ) достигнет вершины, я попытался обернуть его, NotificationListener но это не работает.

Метод, который я испробовал :-

 NotificationListenerlt;OverscrollNotificationgt;(  onNotification: (value) {     if (value.overscroll lt; 0 amp;amp;  widget.scrollController.offset    value.overscroll lt;=  0) {  if (widget.scrollController.offset != 0)  widget.scrollController.jumpTo(0);  } else if (widget.scrollController.offset    value.overscroll gt;=  widget.scrollController.position  .maxScrollExtent) {  if (widget.scrollController.offset !=  widget.scrollController.position  .maxScrollExtent)  widget.scrollController.jumpTo(widget  .scrollController  .position  .maxScrollExtent);  }  widget.scrollController.jumpTo(  widget.scrollController.position.pixels    value.overscroll);  return true;  },  child: ListView(  children: [  Padding(  padding:  const EdgeInsets.only(bottom: 10.0),  child: Text(  listOfCharacters[index]['name'],  textAlign: TextAlign.center,  style: TextStyle(fontSize: 20),  ),  ),  Container(  color: cc[index],  height: 50,  ),  Container(  color: Colors.red,  height: 500,  )  ],  ),  );  

Полный снип кода :

 import 'package:flutter/cupertino.dart'; import 'package:flutter/material.dart'; import 'package:flutter/rendering.dart';  void main() =gt; runApp(  const MyApp(),  );  /// This is the main application widget. 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 MyStatelessWidget(),  ),  );  } }  class MyStatelessWidget extends StatelessWidget {  const MyStatelessWidget({Key key}) : super(key: key);   @override  Widget build(BuildContext context) {  return Center(  child: Stack(children: [  DraggableScrollableSheet(  initialChildSize: 0.6,  minChildSize: 41 / MediaQuery.of(context).size.height,  maxChildSize: 0.6,  builder: (BuildContext context, ScrollController scrollController) {  return ItCrowdPage(  scrollController: scrollController,  );  },  ),  ]));  } }  class ClampScroll extends ScrollBehavior {  @override  Widget buildViewportChrome(  BuildContext context, Widget child, AxisDirection axisDirection) {  return child;  } }  class ItCrowdPage extends StatefulWidget {  final ScrollController scrollController;   const ItCrowdPage({Key key, @required this.scrollController})  : super(key: key);  @override  _ItCrowdPageState createState() =gt; _ItCrowdPageState(); }  class _ItCrowdPageState extends Statelt;ItCrowdPagegt; {  double viewPortFraction = 0.5;   PageController pageController, pageController2;   int currentPage = 0;   Listlt;Maplt;String, Stringgt;gt; listOfCharacters = [  {'name': "Richmond"},  {'name': "Roy"},  {'name': "Moss"},  {'name': "Douglas"},  {'name': "Jen"}  ];  double page = 0.0;  bool sc = false, sc2 = false;  @override  void initState() {  pageController = PageController(  initialPage: currentPage, viewportFraction: viewPortFraction);  pageController2 = PageController(initialPage: currentPage);  super.initState();  }   @override  void dispose() {  pageController.dispose();  pageController2.dispose();  super.dispose();  }   @override  Widget build(BuildContext context) {  return Container(  clipBehavior: Clip.antiAlias,  decoration: const BoxDecoration(  color: Colors.pink,  borderRadius: const BorderRadius.only(  topLeft: Radius.circular(20), topRight: Radius.circular(20))),  child: ScrollConfiguration(  behavior: ClampScroll(),  child: CustomScrollView(  controller: widget.scrollController,  slivers: [  SliverFillRemaining(  child: Column(  children: [  Container(  margin: EdgeInsets.all(10),  width: 42,  height: 6,  decoration: BoxDecoration(  color: Colors.grey.shade300,  borderRadius:  const BorderRadius.all(Radius.circular(8))),  ),  // Expanded(  // child: Container(  // color: Colors.blueAccent,  // ))  const SizedBox(  height: 9,  ),  Flexible(  flex: 1,  fit: FlexFit.loose,  child: NotificationListenerlt;ScrollNotificationgt;(  onNotification: (ScrollNotification notification) {  if (notification is UserScrollNotification amp;amp;  sc == false) {  setState(() {  sc = true;  sc2 = false;  });  // print("i: ll");  } else if (notification is ScrollUpdateNotification) {  if (pageController2.page != pageController.page amp;amp;  sc) {  pageController2.position  .jumpTo(pageController.position.pixels * 2);  }  setState(() {  page = pageController.page;  });  }  return true;  },  child: PageView.builder(  onPageChanged: (pos) {  setState(() {  currentPage = pos;  });  },  physics: BouncingScrollPhysics(),  pageSnapping: sc,  controller: pageController,  itemCount: listOfCharacters.length,  itemBuilder: (context, index) {  return Container(  color: Colors.blueAccent,  );  },  ),  ),  ),  Flexible(  flex: 2,  child: NotificationListenerlt;ScrollNotificationgt;(  onNotification: (ScrollNotification notification) {  if (notification.depth == 0 amp;amp;  notification is UserScrollNotification amp;amp;  sc2 == false) {  setState(() {  // i = 2;  sc = false;  sc2 = true;  });  // print("i: ll");  } else if (notification.depth == 0 amp;amp;  notification is ScrollUpdateNotification amp;amp;  sc2) {  // page = pageController2;  if (pageController2.page != pageController.page) {  pageController.position  .jumpTo(pageController2.position.pixels / 2);  }  }  return true;  },  child: PageView.builder(  pageSnapping: sc2,  controller: pageController2,  onPageChanged: (pos) {  setState(() {  currentPage = pos;  });  },  physics: BouncingScrollPhysics(),  itemCount: listOfCharacters.length,  itemBuilder: (context, index) {  return ListView(  children: [  Padding(  padding: const EdgeInsets.only(bottom: 10.0),  child: Text(  listOfCharacters[index]['name'],  textAlign: TextAlign.center,  style: TextStyle(fontSize: 20),  ),  ),  Container(  color: cc[index],  height: 50,  ),  Container(  color: Colors.red,  height: 500,  )  ],  );  },  ),  ),  ),  ],  ),  ),  ],  ),  ),  );  } }  const Listlt;Colorgt; cc = [  Colors.black,  Colors.green,  Colors.purple,  Colors.yellow,  Colors.blueAccent ];