Flutter切换tab后保留tab状态

BottomNavigationBar+PageView+AutomaticKeepAliveClientMixin

要点

子页面的 class

class _HomePageState with AutomaticKeepAliveClientMixin{// 要点 1
 
 
  @override
  bool get wantKeepAlive => true;// 要点 2
 
  Widget build(BuildContext context){super.build(context);// 要点 3
  }

光上面其实还不够，还需要搭配其他 Widget 使用，例如 BottomNavigationBar+PageView 活着 TabBar+TabbarView，这样页面才不会销毁。

//PageView 是重点的重点

Scaffold(
        body:PageView.builder(physics: NeverScrollableScrollPhysics(),// 禁止页面左右滑动切换
          controller: _pageController,
          onPageChanged: _pageChanged,
          itemCount: _pages.length,
          itemBuilder: (context,index)=>_pages[index]
        )
        bottomNavigationBar:...
)

class MyApp extends StatefulWidget{
  @override
  _MyAppState createState() => _MyAppState();
}
 
class _MyAppState extends State<MyApp>{var _pages = [HomePage(),ListViewDemo(),DemoPage(),UserListPage()]; 
  int _tabIndex = 0;
 
  var _pageController =PageController();
 
  @override
  void dispose() {super.dispose();
    _pageController.dispose();}
 
  Widget build(BuildContext context){
    return MaterialApp(
      theme: ThemeData(primaryColor: Colors.pinkAccent),
      
      home:Scaffold(
        body:PageView.builder(// 要点 1
          physics: NeverScrollableScrollPhysics(),// 禁止页面左右滑动切换
          controller: _pageController,
          onPageChanged: _pageChanged,// 回调函数
          itemCount: _pages.length,
          itemBuilder: (context,index)=>_pages[index]
        ),
        bottomNavigationBar:BottomNavigationBar(
          items: <BottomNavigationBarItem>[BottomNavigationBarItem(title:Text('主页'),icon: Icon(Icons.home)),
            BottomNavigationBarItem(title:Text('商城'),icon: Icon(Icons.shopping_basket)),
            BottomNavigationBarItem(title:Text('测试'),icon: Icon(Icons.pageview)),
            BottomNavigationBarItem(title:Text('我的'),icon: Icon(Icons.account_box)),
          ],
          onTap: (index){print('onTap');
            _pageController.jumpToPage(index);
  
          },      
          type:BottomNavigationBarType.fixed,
          currentIndex: _tabIndex,  
        ),
       
        
      )    
      );
  }
 
  void _pageChanged(int index){print('_pageChanged');
    setState(() {if(_tabIndex != index)
        _tabIndex = index;
    });
  }
  
}
 

class DemoPage extends StatefulWidget {_DemoPageState createState() => _DemoPageState();}
 
class _DemoPageState extends State<DemoPage> with AutomaticKeepAliveClientMixin{// 要点 1
  int _count = 0;
 
  @override
  bool get wantKeepAlive => true;// 要点 2
 
  @override
  Widget build(BuildContext context) {super.build(context);// 要点 3
    return Scaffold(appBar: AppBar(title:Text('Demo Page')),
      body: Center(child:Text('当前计数:$_count')),
      floatingActionButton: FloatingActionButton(child: Icon(Icons.add),
        onPressed: (){setState(() {_count++;});
        },
      ),
    );
  }
}

来源：CSDN
原文：https://blog.csdn.net/weixin_…
版权声明：本文为博主原创文章，转载请附上博文链接！