how to prevent rebuild all widget in IndexedStack? - flutter

Question

I want to rebuild just one widget in IndexedStack.
my app has 5 widgets(PostListScreen,AgendaListScreen ....)in IndexedStack.
PostListSceen have PostContainer.
I can go to PostContainer when I click element in PostListScreen. and then go back to PostListScreen.
5 widgets are all rebuild. I think just PostListScreen widget have to rebuild.
why other widgets also rebuild????. It makes unnecessary communication with server.
class HomeScreen extends StatefulWidget {
const HomeScreen({Key? key}) : super(key: key);
#override
State<HomeScreen> createState() => _HomeScreenState();
}
class _HomeScreenState extends State<HomeScreen> {
PreferredSizeWidget? _appBarContainer(bottomSelectedIndex) {
return (bottomSelectedIndex == 0 || bottomSelectedIndex == 1)
? const AppBarRedContainer()
: AppBarNavigatorContainer(actions: [
IconButton(
padding: EdgeInsets.only(right: 15.0.w),
icon: SvgPicture.asset(
"assets/images/notification_b.svg",
),
iconSize: 24.0.r,
constraints: const BoxConstraints(),
onPressed: () {
Beamer.of(context).beamToNamed('/$locationAlarm');
},
)
], title: (bottomSelectedIndex == 3 ? "핫글 모음" : "내 정보"))
as PreferredSizeWidget;
}
#override
Widget build(BuildContext context) {
int bottomSelectedIndex =
Provider.of<IndexNotifier>(context, listen: false).bottomSelectedIndex;
StockModel stock = Provider.of<StockCodeNotifier>(context, listen: false).stock;
if (stock.code == null) {
Provider.of<StockCodeNotifier>(context, listen: false).getStocks();
stock = Provider.of<StockCodeNotifier>(context, listen: false).stock;
FlutterNativeSplash.remove();
}
return Scaffold(
appBar: _appBarContainer(bottomSelectedIndex),
body: SafeArea(
child: IndexedStack(
index: bottomSelectedIndex,
children: [
PostListScreen(stock: stock),
AgendaListScreen(
stock: stock,
),
WriteScreen(
stockCode: stock.code!,
),
const HotListScreen(),
const MyInfoScreen()
],
),
),
);
}
}
postListScreen.dart
class PostListScreen extends StatefulWidget {
const PostListScreen({Key? key, required this.stock}) : super(key: key);
final StockModel stock;
#override
State<PostListScreen> createState() => _PostListScreenState();
}
class _PostListScreenState extends State<PostListScreen> {
late Future<List<PostModel>> _postData;
bool init = false;
#override
void initState() {
if(!init){
_postData = _fetchPostData();
init = true;
}
super.initState();
}
Future<List<PostModel>> _fetchPostData() async {
return await PostListService().getPosts(widget.stock.code!);
}
Future<void> _onRefresh() async {
setState(() {});
Future.value(null);
}
#override
Widget build(BuildContext context) {
return FutureBuilder<List<PostModel>>(
future: _postData,
builder: (context, snapshot) {
return RefreshIndicator(
onRefresh: _onRefresh,
child: CustomScrollView(slivers: [
SliverAppBar(
floating: true,
expandedHeight: 148.0.h,
flexibleSpace: FlexibleSpaceBar(
background: StockInfo(
stockCount: widget.stock.count!,
stockName: widget.stock.name!,
),
),
),
(snapshot.hasData == false)
? const SliverFillRemaining(
child: Center(child: CircularProgressIndicator()))
: (snapshot.data!.isNotEmpty)
? _sliverList(snapshot.data!)
: SliverFillRemaining(
child: NoContentContainer(
onRefresh: _onRefresh,
noText: "이야기가 없어요",
offerText: '첫 이야기를 작성해 보시는 건 어떨까요?'),
),
]),
);
});
}
}