flutter - 带有Firestore的Flutter搜索代表

Question

我正在使用Flutter Search Delegate实现搜索功能，并且数据存储在Firestore中。我不知道为什么会出现此错误。

Widget buildSuggestions(BuildContext context) {
  return StreamBuilder(
    stream: Firestore.instance.collection('todos').snapshots(),
    builder: (context, snapshot) {
      if (!snapshot.hasData) return new Text('Loading...');

      final results =
          snapshot.data.documents.where((a) => a['title'].contains(query));

      return ListView(
        children: results.map<Widget>((a) => Text(a['title'])).toList(),
      );
    },
  );
}

错误:
type '(dynamic) => dynamic' is not a subtype of type '(DocumentSnapshot) => bool' of 'test'

Answer 1

更换线

final results = snapshot.data.documents.where((a) => a['title'].contains(query));

至

final results = snapshot.data.documents.where((DocumentSnapshot a) => a.data['title'].contains(query));

和线

children: results.map<Widget>((a) => Text(a['title'])).toList()

至

children: results.map<Widget>((a) => Text(a.data['title'])).toList()