如何将用户名存储在包含 email 和同一用户发送的聊天消息的同一文档中？ 在 flutter 和 firebase

Question

I want to store the username in the same document that will contain a message from this user so that I can display the message with the username, but I could not get the username from the new account registration page, I could only get the sender's email and add it to the document for each message.

New user registration page:

 

  const RegistrationScreen({Key? key}) : super(key: key);

  @override
  _RegistrationScreenState createState() => _RegistrationScreenState();
}

class _RegistrationScreenState extends State<RegistrationScreen> {
  final _auth = FirebaseAuth.instance;

  late String email;
  late String password;
  late String username;

  bool showSpinner = false;

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      backgroundColor: Colors.white,
      body: Column(
        mainAxisAlignment: MainAxisAlignment.center,
        crossAxisAlignment: CrossAxisAlignment.stretch,
        children: [
          TextField(
            onChanged: (value) {
              username = value;
            },
            decoration: InputDecoration(
              hintText: 'username',
            ),
          ),
          TextField(
            onChanged: (value) {
              email = value;
            },
            decoration: InputDecoration(
              hintText: 'email',
            ),
          ),
          TextField(
            onChanged: (value) {
              password = value;
            },
            decoration: InputDecoration(
              hintText: 'password',
            ),
          ),
          ElevatedButton(
            child: Text('register'),
            onPressed: () async {
              try {
                final newUser = await _auth.createUserWithEmailAndPassword(
                    email: email, password: password);
                Navigator.pushNamed(context, ChatScreen.screenRoute);
                setState(() {
                  showSpinner = false;
                });
              } catch (e) {
                print(e);
              }
            },
          )
        ],
      ),
    );
  }
}

The chat page: on this page I get the sender's email and his message in a document, then I display it again in the application, and now I also want to get the username to display it with the message.

final _firestore = FirebaseFirestore.instance;
late User signedInUser;

class ChatScreen extends StatefulWidget {


  const ChatScreen({Key? key}) : super(key: key);

  @override
  _ChatScreenState createState() => _ChatScreenState();
}

class _ChatScreenState extends State<ChatScreen> {
  final messageTextController = TextEditingController();
  final _auth = FirebaseAuth.instance;

  String? messageText;
  @override
  void initState() {
    super.initState();
    getCurrentUser();
  }

  void getCurrentUser() {
    try {
      final user = _auth.currentUser;
      if (user != null) {
        signedInUser = user;
        print(signedInUser.email);
      }
    } catch (e) {
      print(e);
    }
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      body: Column(
        children: [
          messageStreamBuilder(),
          Container(
            child: Row(
              children: [
                Expanded(
                  child: TextField(
                    controller: messageTextController,
                    onChanged: (value) {
                      messageText = value;
                    },
                    decoration: InputDecoration(
                      hintText: 'Write your message here...',
                    ),
                  ),
                ),
                TextButton(
                  onPressed: () {
                    messageTextController.clear();
                    _firestore.collection('messages').add({
                      'text': messageText,
                      'sender': signedInUser.email,
                     
                    });
                  },
                  child: Text(
                    'send',
                  ),
                )
              ],
            ),
          ),
        ],
      ),
    );
  }
}

class messageStreamBuilder extends StatelessWidget {
  const messageStreamBuilder({Key? key}) : super(key: key);

  @override
  Widget build(BuildContext context) {
    return StreamBuilder<QuerySnapshot>(
        stream: _firestore.collection('messages').snapshots(),
        builder: (context, snapshot) {
          List<messageLine> messageWidgets = [];
          if (!snapshot.hasData) {
            return CircularProgressIndicator(
              backgroundColor: Colors.blue,
            );
          }
          final messages = snapshot.data!.docs;
          for (var message in messages) {
            final messageText = message.get('text');
            final messageSender = message.get('sender');

            final currentUser = signedInUser.email;

            final messageWidget = messageLine(
              sender: messageSender,
              text: messageText,
            );
            messageWidgets.add(messageWidget);
          }
          return Expanded(
            child: ListView(
              padding: EdgeInsets.symmetric(horizontal: 10, vertical: 20),
              children: messageWidgets,
            ),
          );
        });
  }
}

class messageLine extends StatelessWidget {
  const messageLine({this.text, this.sender, Key? key}) : super(key: key);

  final String? sender;
  final String? text;

  @override
  Widget build(BuildContext context) {
    return Padding(
      padding: EdgeInsets.all(10),
      child: Column(
        crossAxisAlignment: CrossAxisAlignment.start,
        children: [
          Text(
            '$sender',
          
          ),
          Material(
            child: Text(
              '$text',
            
            ),
          ),
        ],
      ),
    );
  }
}

Answer 1

in this function, You can use like this to achive that

 void getCurrentUser() {
    try {
      final user = _auth.currentUser;
      if (user != null) {
        String user_Name = user.displayName;
        String image_Url = user.photoUrl;
        String email_Id = user.email;
        String user_Uuid = user.uid; // etc
        print(user_Name );
      }
    } catch (e) {
      print(e);
    }
  }

after that pass the user_name to firebase