Flutter Page View dispose children，如何留住children和bloc答案

【问题标题】：Flutter Page View dispose children, how to keep children and blocFlutter Page View dispose children，如何留住children和bloc
【发布时间】：2020-08-18 10:15:05
【问题描述】：

我有下一个代码结构，当我滑动到下一页时，pageview distroy previos page(widget and bloc)
home: SafeArea( child: PageView(controller: _pageController, children: [ Scaffold( body: BlocProvider<Bloc>( bloc: bloc, child: Container()), Scaffold( body: BlocProvider<Bloc>( bloc: bloc, child: Container()) Scaffold( body: BlocProvider<Bloc>( bloc: bloc, child: Container()))) 当 pageview 更改页面时，如何使用小部件保存 bloc 类？

【问题讨论】：

标签： android flutter dart flutter-layout

【解决方案1】：

PageView 的孩子需要一个 StatefullWidget 并且 StatefullWidget 的状态是添加 with AutomaticKeepAliveClientMixin

例子：

class _SearchPageState extends State<SearchPage>
    with AutomaticKeepAliveClientMixin {
  static const TAG = 'SearchPage';

  VoidCallback onTapSort, onTapArea, onTapDatePicker, onTapFilter;

  SearchPageFilter searchFilter;

  WorkBloc _workBloc;

  VoidCallback onReloadPage;

  @override
  void initState() {
    super.initState();

  @override
  Widget build(BuildContext context) {
    super.build(context);
    return ChangeNotifierProvider.value(
      value: searchFilter,
      child: Scaffold(
        appBar: AppBar(
          title: Text(AppLocalizations.of(context).titleSearchPage),
          bottom: PreferredSize(
              child: SearchSliverPersistentHeaderDelegate(
                  onTapSort, onTapArea,
                  onTapDatePicker: onTapDatePicker,
                  onTapFilter: onTapFilter),
              preferredSize: Size.fromHeight(128)),
        ),
        body: Builder(
            builder: (context) {
              //.....
            }
        ),
      ),
    );
  }

  @override
  bool get wantKeepAlive => true;
}

【讨论】：