flutter - 如何在flutter中使用firestore刷新streamBuilder

Question

我在管理流生成器时迷失了方向……请帮忙！

我有一个很棒的类，它从 firestore 获取数据并将其呈现为列表。流包含一个变量 ( rag)，它可以根据用户交互进行更改，我希望流在此类变量更改时更新。我无法让它工作，我相信我的问题是我无法刷新流。如何刷新我的流？在 iOS 中有一个简单的 reloadData 行...

请参阅下面我的代码

class RestaurantList extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return StreamBuilder<QuerySnapshot>(
      stream: _firestore
          .collection('restaurants')
          .where('lat', isGreaterThan: appData.currentLatitude - rag)
          .where('lat', isLessThan: appData.currentLatitude + rag)
          .snapshots(),
      builder: (context, snapshot) {
        if (snapshot.hasError) return new Text('Error: ${snapshot.error}');
        switch (snapshot.connectionState) {
          case ConnectionState.waiting:
            return Center(
              child: new Text(
                'Loading...',
              ),
            );
          default:
            final restDB = snapshot.data.documents;

              for (var rest in restDB) {
                final restID = rest.documentID;
                final name = rest.data['name'];
                final lati = rest.data['lat'];
                final longi = rest.data['lon'];
                final distance = (appData.currentLatitude - lati) *
                        (appData.currentLatitude - lati) +
                    (appData.currentLongitude - longi) *
                        (appData.currentLongitude - longi);

                if (longi < appData.currentLongitude + rag &&
                    longi > appData.currentLongitude - rag) {
                  final restaurant = Restaurant(
                    restID: restID,
                    name: name,
                    distance: distance,
                    lati: lati,
                    longi: longi,
                  );

                  restaurants.add(restaurant);

                }
              }      

            return ListView(
              shrinkWrap: true,
              physics: ClampingScrollPhysics(),
              children: restaurants,
            );
        }
      },
    );
  }
}