android - 错误状态 : field does not exist within the DocumentSnapshotPlatform . 它表明 getter 是在 null 上调用的

Question

导致错误的相关小部件是流生成器。我已经在 github 中给出了项目存储库的链接。

Widget build(BuildContext context) {
return StreamBuilder(
  stream: FirebaseFirestore.instance
      .collection("/chats/2DGQmBssJ4sU6MVJZYc0/messages")
      .orderBy('createdAt', descending: true)
      .snapshots(),
  builder: (context, snapshot) {
    if (snapshot.connectionState == ConnectionState.waiting)
      Center(child: CircularProgressIndicator());
    final documents = snapshot.data.documents;
    return ListView.builder(
      reverse: true,
      itemCount: documents.length,
      itemBuilder: (context, index) {
        return MessageBubble(
            documents[index]['text'],
            documents[index]['userID'] == user.uid,
            documents[index]['userID'],
            documents[index]['imageurl']);
      },
    );
  },
);

}}

Github link of the project

Answer 1

尝试以下操作:

 if (snapshot.connectionState == ConnectionState.waiting)
      Center(child: CircularProgressIndicator());
 else if(snapshot.connectionState == ConnectionState.active){
    final documents = snapshot.data.documents;
    return ListView.builder(
      reverse: true,
      itemCount: docs.length,
      itemBuilder: (context, index) {
        return MessageBubble(
            docs[index]['text'],
            docs[index]['userID'] == user.uid,
            docs[index]['userID'],
            docs[index]['imageurl']);
       },
     );
   },
  },
);

当连接状态为 Activity 状态且数据非空时，则检索数据。另外，请使用 docs，因为您似乎正在使用新版本的 Firestore。

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