firebase - 未为颤动图表加载 Firebase 数据

Question

我是颤振图表的新手，如下面的代码片段所示，使用基准变量（List）创建系列（列表>）对象时，它没有显示任何错误，但是当我使用数据变量 c（列表）创建相同的系列时，它是从firebase加载它会引发以下错误，我应该怎么做才能解决这个错误

I/flutter (28785): The following assertion was thrown building StreamBuilder<QuerySnapshot>(dirty, state:
I/flutter (28785): _StreamBuilderBaseState<QuerySnapshot, AsyncSnapshot<QuerySnapshot>>#84465):
I/flutter (28785): type 'List<dynamic>' is not a subtype of type 'List<Support>'

代码

StreamBuilder(
      stream: Firestore.instance
          .collection("sports")
          .document("footballl")
          .collection("most_goals")
          .snapshots(),
      builder: (context, snapshot) {
        if (!snapshot.hasData) {
          return LinearProgressIndicator();
        } else {
          var c =snapshot.data.documents.map((documentsnap) => Support.frommap(documentsnap.data)).toList();          
          print(c);
          var datum = [
            Support("chandru",50),
            Support("eazy",100)
          ];
          print(datum);
          var series = List<charts.Series<Support, String>>();

          series.add(
            charts.Series(
              domainFn: (Support s,_)=>s.domain,
              measureFn: (Support s,_)=>s.measure,
              id: "data",
              data: c
            ));

          print(series);
          return chart(context,series);
        }
      },
    );

标签： firebaseflutterdartcharts