为什么我的函数没有在flutter dart中调用

Question

这是使用streambuilder和列表视图从firestore获取消息文本的代码。我不知道为什么_buildlistitem不起作用。我也尝试打印数字来检查它，但没有用。有人可以帮忙吗

Widget _buildMessagesList() {
    print(1);
    return StreamBuilder(
      stream:
          _chatService.getMessages(widget.receiveruid, _auth.currentUser!.uid),
      builder: (context, snapshot) {
        if (snapshot.hasError) {
          return Text('Error ${snapshot.error}');
        }
        if (snapshot.connectionState == ConnectionState.waiting) {
          return const Text('Loading');
        }
        if (snapshot.data == null) {
          return Text('No data available');
        } else {
          return ListView(
            children: snapshot.data!.docs
                .map((doc) => _buildMessageItem(doc))
                .toList(),
          );
        }
      },
    );
  }

Widget _buildMessageItem(DocumentSnapshot document) {
    Map<String, dynamic> data = document.data() as Map<String, dynamic>;
    print(3);
    var alignment = (data['senderId'] == _auth.currentUser!.uid)
        ? Alignment.centerRight
        : Alignment.centerLeft;

    return Container(
      alignment: alignment,
      child: Column(
        children: [
          Text(data['senderEmail']),
          Text(data['message']),
        ],
      ),
    );
  }

我想在代码中调用函数_buildMessageItem。

Answer 1

上课

ChatService

在方法中

Stream<QuerySnapshot> getMessages(String userId, String otherUserId)

将'时间戳'更改为'时间'

错误

.orderBy('timestamp', descending: false)

固定

.orderBy('time', descending: false)

  Stream<QuerySnapshot> getMessages(String userId, String otherUserId) {
    List<String> ids = [userId, otherUserId];
    ids.sort();
    String chatRoomId = ids.join("_");
    print(2);
    return _store
        .collection('chat_rooms')
        .doc(chatRoomId)
        .collection('messages')
        .orderBy('time', descending: false)
        .snapshots();
  }

在消息映射中使用

'time': timestamp,

  Map<String, dynamic> toMap() {
    return {
      'senderId': senderid,
      'senderEmail': senderemail,
      'receiverId': receiverid,
      'message': message,
      'time': timestamp,
    };
  }