无法使用 Stream flutter 再次加载数据

如何解决无法使用 Stream flutter 再次加载数据

我在应用程序启动时使用流数据从 API 加载数据。但是它有一个问题，当它加载 SearchPage 小部件时，快照有数据但是当我切换到其他屏幕并返回到 SearchPage 小部件时，它丢失所有数据。

class _SearchPageState extends State<SearchPage> with TickerProviderStateMixin {
  final locationsstream = StreamController<List<Weather>>.broadcast();
  late final AnimationController _controller = AnimationController(
    duration: const Duration(seconds: 2),vsync: this,)..repeat(reverse: true);
  late final Animation<double> _animation = CurvedAnimation(
    parent: _controller,curve: Curves.elasticOut,);

  @override
  void dispose() {
    _controller.dispose();
    super.dispose();
     locationsstream.close();
  }

  @override
  void initState() {
    loadData();
    // Todo: implement initState
    super.initState();
  }

  void loadData() async {
    WeatherRepo weatherRepo = WeatherRepo();
    List<Weather> RSS = await weatherRepo.loadMainLocations();
    locationsstream.sink.add(RSS);
  }

调用流数据时的代码：

 Container(
                        height: 300,child: StreamBuilder<List<Weather>>(
                            stream: locationsstream.stream,initialData: null,builder: (context,snap) {
                              if (!snap.hasData) {
                                return Container(
                                  child: Center(
                                    child: CircularProgressIndicator(),),);
                              }
                              final data = snap.data;
                              return Container(
                                  height: 300,child: CarouselSlider(
                                      items: <Widget>[
                                        for (Weather w in data!) MainLocation(location: w),],options: CarouselOptions(
                                        height: 300.0,autoplay: true,autoplayInterval: Duration(seconds: 3),autoplayAnimationDuration: Duration(milliseconds: 2000),autoplayCurve: Curves.fastOutSlowIn,enlargeCenterPage: true,scrollDirection: Axis.horizontal,))
                              );}

应用启动时

当我去其他屏幕并回来时

解决方法

试试这个

final StreamController<List<Weather>> locationsStream =
      StreamController<List<Weather>>.broadcast();

@override
void initState() {
  super.initState();
  WidgetsBinding.instance.addPostFrameCallback((_) async {
   await loadData();
  });
}

void loadData() async {
 WeatherRepo weatherRepo = WeatherRepo();
 List<Weather> rss = await weatherRepo.loadMainLocations();
 locationsStream.add(rss);
}