首先说一下，这两种方法只是做到只执行一次initState，并不能做到只执行一次build方法。
有2种方法
- TabBarView中的widget需要继承StatefulWidget，然后它的State继承AutomaticKeepAliveClientMixin，wantKeepAlive返回true，例如下面的代码：
class HomePage extends StatefulWidget {
@override
HomePageState createState() {
return new HomePageState();
}
}
class _HomePageState extends State<HomePage> with AutomaticKeepAliveClientMixin<HomePage>{
@override
Widget build(BuildContext context) {
super.build(context);
}
@protected
bool get wantKeepAlive=>true;
}
- 使用TabBarView的widget使用IndexedStack存储页面，这样的话_HomePageState可以不需要继承AutomaticKeepAliveClientMixin
class MainPage extends StatefulWidget {
@override
_MainPageState createState() => _MainPageState();
}
class _MainPageState extends State<MainPage> with SingleTickerProviderStateMixin<MainPage> {
int _bottomIndex = 0;
Color activeColor = AppColor.PRIMARY_COLOR;
List<String> _titles = <String>["首页", "我的"];
@override
Widget build(BuildContext context) {
return MaterialApp(
title: App.APP_NAME,
theme: ThemeData(
primarySwatch: AppColor.PRIMARY_COLOR,
),
home: Scaffold(
appBar: AppBar(
title: Center(
child: Text(_titles[_bottomIndex]),
),
),
body: body: IndexedStack(
children: <Widget>[
HomePage(),
MePage(),
],
index: _bottomIndex,
),
bottomNavigationBar: BottomNavigationBar(
currentIndex: _bottomIndex,
onTap: (index) {
setState(() {
_bottomIndex = index;
});
},
items: [
BottomNavigationBarItem(
activeIcon: Icon(Icons.home, color: _bottomIndex == 0 ? activeColor : null),
icon: Icon(Icons.home),
title: Text(_titles[0])),
BottomNavigationBarItem(
activeIcon: Icon(Icons.person, color: _bottomIndex == 1 ? activeColor : null),
icon: Icon(Icons.person),
title: Text(_titles[1]))
]),
),
initialRoute: AppRoute.ROUTE_MAIN,
);
}
}
但是用过TabView以后就会发现有很多bug，在我的这篇文章里解决了该问题
https://juejin.im/post/5cde82346fb9a07f04201760
