如何在streambuilder中查询firestore文档并更新listview

2 回答

• -1

  我发布了一个类似的问题，后来找到了一个解决方案：让itemBuilder返回状态的小部件并在其中使用FutureBuilder .

  Additional query for every DocumentSnapshot within StreamBuilder

  这是我的代码 . 在您的情况下，您可能希望使用新的Stateful小部件而不是ListTile，因此您可以添加FutureBuilder来调用异步函数 .

  StreamBuilder(
                    stream: Firestore.instance
                        .collection("messages").snapshots(),
                    builder: (context, snapshot) {
                      switch (snapshot.connectionState) {
                        case ConnectionState.none:
                        case ConnectionState.waiting:
                          return Center(
                            child: PlatformProgressIndicator(),
                          );
                        default:
                          return ListView.builder(
                            reverse: true,
                            itemCount: snapshot.data.documents.length,
                            itemBuilder: (context, index) {
                              List rev = snapshot.data.documents.reversed.toList();
                              ChatMessageModel message = ChatMessageModel.fromSnapshot(rev[index]);
                              return ChatMessage(message);
                            },
                          );
                      }
                    },
                  )
  
  
  class ChatMessage extends StatefulWidget {
    final ChatMessageModel _message;
    ChatMessage(this._message);
    @override
    _ChatMessageState createState() => _ChatMessageState(_message);
  }
  
  class _ChatMessageState extends State<ChatMessage> {
    final ChatMessageModel _message;
  
    _ChatMessageState(this._message);
  
    Future<ChatMessageModel> _load() async {
      await _message.loadUser();
      return _message;
    }
  
    @override
    Widget build(BuildContext context) {
  
      return Container(
        margin: const EdgeInsets.symmetric(horizontal: 10.0, vertical: 10.0),
        child: FutureBuilder(
          future: _load(),
          builder: (context, AsyncSnapshot<ChatMessageModel>message) {
            if (!message.hasData)
              return Container();
            return Row(
              children: <Widget>[
                Container(
                  margin: const EdgeInsets.only(right: 16.0),
                  child: GestureDetector(
                    child: CircleAvatar(
                      backgroundImage: NetworkImage(message.data.user.pictureUrl),
                    ),
                    onTap: () {
                      Navigator.of(context)
                          .push(MaterialPageRoute(builder: (context) => 
                          ProfileScreen(message.data.user)));
                    },
                  ),
                ),
                Expanded(
                  child: Column(
                    crossAxisAlignment: CrossAxisAlignment.start,
                    children: <Widget>[
                      Text(
                        message.data.user.name,
                        style: Theme.of(context).textTheme.subhead,
                      ),
                      Container(
                          margin: const EdgeInsets.only(top: 5.0),
                          child: _message.mediaUrl != null
                              ? Image.network(_message.mediaUrl, width: 250.0)
                              : Text(_message.text))
                    ],
                  ),
                )
              ],
            );
          },
        ),
      );
    }
  }
  class ChatMessageModel {
    String id;
    String userId;
    String text;
    String mediaUrl;
    int createdAt;
    String replyId;
    UserModel user;
  
    ChatMessageModel({String text, String mediaUrl, String userId}) {
      this.text = text;
      this.mediaUrl = mediaUrl;
      this.userId = userId;
    }
  
    ChatMessageModel.fromSnapshot(DocumentSnapshot snapshot) {
      this.id = snapshot.documentID;
      this.text = snapshot.data["text"];
      this.mediaUrl = snapshot.data["mediaUrl"];
      this.createdAt = snapshot.data["createdAt"];
      this.replyId = snapshot.data["replyId"];
      this.userId = snapshot.data["userId"];
    }
  
    Map toMap() {
      Map<String, dynamic> map = {
        "text": this.text,
        "mediaUrl": this.mediaUrl,
        "userId": this.userId,
        "createdAt": this.createdAt
      };
      return map;
  
    }
  
    Future<void> loadUser() async {
      DocumentSnapshot ds = await Firestore.instance
          .collection("users").document(this.userId).get();
      if (ds != null)
        this.user = UserModel.fromSnapshot(ds);
    }
  
  }
  

  回复于 2024-04-27T18:14:45+08:00
• 0

  我也有这个问题，我正在尝试查询其子集合中的字段等于userid的特定文档

  回复于 2024-04-27T18:14:45+08:00