anchor.diff:  
       ///底部tab bar
       return new Scaffold(
  -        drawer: widget.drawer,
  +        drawer: _drawer,
           appBar: new AppBar(
             backgroundColor: Theme.of(context).primaryColor,
  -          title: widget.title,
  +          title: _title,
           ),
           body: new TabBarView(
  -            //TabBarView呈现内容，因此放到Scaffold的body中
  +          //TabBarView呈现内容，因此放到Scaffold的body中
               controller: _tabController, //配置控制器
  -            children: widget.tabViews),
  +            children: _tabViews),
           bottomNavigationBar: new Material(
             //为了适配主题风格，包一层Material实现风格套用
             color: Theme.of(context).primaryColor, //底部导航栏主题颜色
  
positive.code:             //TabBar导航标签，底部导航放到Scaffold的bottomNavigationBar中
              controller: _tabController, //配置控制器
              tabs: widget.tabItems,
              indicatorColor: widget.indicatorColor, //tab标签的下划线颜色
            ),
          ));
    }
  
negative.code: 
    @override
    Widget build(BuildContext context) {
      if (this._type == GSYTabBarWidget.TOP_TAB) {
        ///顶部tab bar
        return new Scaffold(
          floatingActionButton: _floatingActionButton,
          persistentFooterButtons: _tarWidgetControl == null ? [] : _tarWidgetControl.footerButton,
          appBar: new AppBar(
            backgroundColor: Theme.of(context).primaryColor,
            title: _title,
            bottom: new TabBar(
              controller: _tabController,
              tabs: widget.tabItems,
              indicatorColor: _indicatorColor,
            ),
          ),
          body: new PageView(
            controller: _pageController,
            children: _tabViews,
            onPageChanged: (index) {
              _tabController.animateTo(index);
              _onPageChanged?.call(index);
            },
          ),
        );
  