我在nestedscrollview 中的SliverAppBar 不会出现或消失，直到我从滚动中抬起手指，

问题描述

我实际上是在尝试实现与 whatsapp for android 中相同的效果，即应用栏在向下滚动时消失并在向上滚动时重新出现的方式 这是我试过的，但我没有得到我想要的效果，appbar 没有立即出现或消失，它一直等到我把手离开屏幕

ScrollController scrollController;
TabController tabController;
TextStyles textStyles = TextStyles();

@override
  void initState() {
    super.initState();
    tabController = TabController(length: 5,vsync: this);
    scrollController = ScrollController();
  }

  @override
  void dispose() {
    // Todo: implement dispose
    super.dispose();
    tabController.dispose();
    scrollController.dispose();
  }

  @override
  Widget build(BuildContext context) {
    final colors = AppColors();
    final actionIcon = Icon(
      Icons.search,color: Colors.white,);
    final Function onpressed = () {};
    return Scaffold(
      body: nestedScrollView(
        floatHeaderSlivers: true,controller: scrollController,headerSliverBuilder: (_,innerBoxIsScrolled) => [
          buildSliverAppBar(innerBoxIsScrolled,colors,actionIcon,onpressed)
        ],body: buildTabBarView(),),);
  }

  //build tabbar
  TabBarView buildTabBarView() {
    return TabBarView(controller: tabController,children: [
      HoMetabPage(
        tabTitle: 'Featured',HoMetabPage(tabTitle: 'Online Now'),HoMetabPage(tabTitle: 'New to jiko'),HoMetabPage(tabTitle: 'discounts'),Categories()
    ]);
  }

  //build the appbar (containing the logo and the search)
  SliverAppBar buildSliverAppBar(bool innerBoxIsScrolled,AppColors colors,Icon actionIcon,Function onpressed) {
    return SliverAppBar(
      title: Padding(
        padding: const EdgeInsets.only(top: 16),child: Text('logo'),elevation: 0,snap: true,floating: true,pinned: true,bottom: PreferredSize(
        preferredSize: Size.fromHeight(50),child: Align(
          alignment: AlignmentDirectional.centerStart,child: Padding(
            padding: const EdgeInsets.only(left: 8),child: TabBar(
                unselectedLabelColor: colors.greyText,labelPadding: EdgeInsets.symmetric(horizontal: 8),indicatorSize: TabBarIndicatorSize.label,isScrollable: true,controller: tabController,labelStyle: textStyles.subtitle2,tabs: [
                  Tab(
                    text: 'Featured',Tab(
                    text: 'Online Now',Tab(
                    text: 'New to jiko',Tab(
                    text: 'discounts',Tab(
                    text: 'Categories',]),actions: [
        ActionButton(colors: colors,icon: actionIcon,onpressed: onpressed)
      ],);
  }

解决方法

暂无找到可以解决该程序问题的有效方法，小编努力寻找整理中！

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