Flutter实现嵌套的SliverPersistentHeader

如何解决Flutter实现嵌套的SliverPersistentHeader

在我的应用程序中，我在父级中有一个SliverPersistentHeader，在内部我想与SliverList一起使用另一个SliverPersistentHeader，我在下面有一个伪代码，然后得到

应用父数据时引发了以下断言： 错误使用ParentDataWidget。

ParentDataWidget Expanded（flex：1）要应用的ParentData 将FlexParentData类型键入RenderObject，该对象已设置为接受 类型不兼容的ParentData的ParentData。

通常，这表示扩展窗口小部件的祖先错误 RenderObjectWidget。通常，扩展小部件直接放置 在Flex小部件中。违规扩展目前位于内部 一个RepaintBoundary小部件。

已接收到RenderObject的所有权链 不兼容的父数据为：RepaintBoundary← NotificationListener←GlowingOverscrollIndicator ←可滚动←_nestedScrollViewCustomScrollView←构建器← _InheritednestedScrollView←nestedScrollView←扩展←RepaintBoundary←⋯

════════渲染库捕获的异常═══════RenderBox是 未布置：RendernestedScrollViewViewport＃e9060 NEEDS-LAYOUT 需求油漆需求组成位更新 'package：Flutter / src / rendering / Box.dart'：断言失败：1785行 pos 12：“ hasSize”相关的引起错误的小部件是：
nestedScrollView 文件：/// C：/Users/mahdi/AndroidStudioProjects/instacheeta/lib/nested.dart：41：26 ══════════════════════════════════════════════════ ════

错误，当我尝试删除Expanded小部件时，出现另一个错误。

我该如何解决？

import 'package:Flutter/material.dart';

void main()=>runApp(MySliverApp());

class MySliverApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'sample',home: MySilverHomeApp(),);
  }
}

class MySilverHomeApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return Scaffold(
      body: CustomScrollView(
        physics: const ClampingScrollPhysics(),slivers: <Widget>[
          SliverPersistentHeader(
            pinned: false,floating: true,delegate: CustomAutoHideAppBarDelegate(
              child: Padding(
                padding: const EdgeInsets.symmetric(horizontal: 12.0),child: Row(
                  children:const <Widget>[
                     Text('SAMPLE')
                  ],),SliverPadding(
            padding: const EdgeInsets.all(0),sliver: SliverList(
              delegate: SliverChildListDelegate([
                Expanded(
                  child: nestedScrollView(
                    headerSliverBuilder: (BuildContext context,bool innerBoxIsScrolled) {
                      return <Widget>[
                        SliverList(
                          delegate: SliverChildBuilderDelegate((BuildContext context,int index) {
                            return Column(
                              children:const <Widget>[
                                Text('SAMPLE'),Text('SAMPLE')
                              ],);
                          },childCount: 1),SliverPersistentHeader(
                          pinned: true,delegate: ContestTabHeader(
                            Text('SAMPLE'),];
                    },body: ListView.builder(itemBuilder: (context,index){
                      return Container(
                        child: Text('$index'),);
                    },itemCount: 100,)),]),],);
  }
}

class CustomAutoHideAppBarDelegate extends SliverPersistentHeaderDelegate {
  const CustomAutoHideAppBarDelegate({
    @required this.child,});

  final Widget child;

  @override
  Widget build(BuildContext context,double shrinkOffset,bool overlapsContent) {
    final theme = Theme.of(context);
    return SizedBox.expand(
      child: Material(
        color: Colors.white,elevation: 3,child: Padding(
          padding: EdgeInsets.only(
            top: MediaQuery.of(context).padding.top,child: DefaultTextStyle.merge(
            style: theme.primaryTextTheme.subtitle1,child: IconTheme.merge(
              data: theme.primaryIconTheme,child: child,);
  }

  @override
  double get minextent => kToolbarHeight;

  @override
  double get maxExtent => kToolbarHeight;

  @override
  bool shouldRebuild(CustomAutoHideAppBarDelegate oldDelegate) => child != oldDelegate.child;
}
class ContestTabHeader extends SliverPersistentHeaderDelegate {
  ContestTabHeader(
      this.searchUI,);

  final Widget searchUI;

  @override
  Widget build(BuildContext context,bool overlapsContent) {
    return searchUI;
  }

  @override
  double get maxExtent => 52.0;

  @override
  double get minextent => 52.0;

  @override
  bool shouldRebuild(SliverPersistentHeaderDelegate oldDelegate) {
    return false;
  }
}