Exception while retrieving the data :- RenderBox was not laid out

Issue

I am building a chatApp with a login Screen and a Register Screen. After authenticating it (register and login) you can start chatting with other users. I added a controller property to my textField after that my code is crashing even after removing the controller. The line of the error is not mentioned. As soon as its starts loading the chats I am getting an exception.

Exception caught by rendering library

The following assertion was thrown during performLayout():

RenderBox was not laid out: RenderRepaintBoundary#7b139 relayoutBoundary=up3 NEEDS-PAINT NEEDS-COMPOSITING-BITS-UPDATE
‘package:flutter/src/rendering/box.dart’:
Failed assertion: line 1929 pos 12: ‘hasSize’

Either the assertion indicates an error in the framework itself, or we should provide substantially more information in this error message to help you determine and fix the underlying cause.

Here is my code:

import 'package:flutter/cupertino.dart';
import 'package:flutter/material.dart';
import 'package:flashchat1/constants.dart';
import 'package:firebase_auth/firebase_auth.dart';
import 'package:cloud_firestore/cloud_firestore.dart';
final _fireStore = FirebaseFirestore.instance;//an instance of fireBase store that stored data created
final _auth = FirebaseAuth.instance;//instance/object of fireBase auth that authorizes users is created
class ChatScreen extends StatefulWidget {
  static String id='Chat_Screen';
  @override
  _ChatScreenState createState() => _ChatScreenState();
}

class _ChatScreenState extends State<ChatScreen> {
  final messageTextController = TextEditingController();
  late User loggedInUser;//LoggedInUser is of type FireBase user(now changed to user)
  late String messageText;
  @override
  void initState()
  {
    super.initState();
    getCurrentUser();//calling the getCurrentUser
  }
  void getCurrentUser()
  async{
    try
    {
      final user= await _auth.currentUser;//get the current user id/name/email.Also currentUser return a future so make it async by adding await and async keywords
      if(user!=null)
      {
        loggedInUser=user ;//LoggedInUser = user contains email of the info
        print(loggedInUser.email);
      }

    }
    catch(e)
    {
      print(e);
    }
  }// Under collection there is documents.Inside documents there are fields like type ,values etc.These fields contain our information
    Future<void> messageStream()//Using a stream it becomes very easy .U just need to click once after you run the app .Then u will be done.
    async {//The snapShot here is FireBase's Query SnapShot
      await for(var snapshot in _fireStore.collection('messages').snapshots()){//make a variable snapshot to store the entire items of the collection in fireBase (Look at the fireBase console there is a collection called messages).This collection takes the snapshot of all the iteams (not literal snapshot .Think it like a snapShot)
        for(var message in snapshot.docs)//make a variable message to access the snapShot.docs .(docs stands for Documentation.Look at the fireBase console)
        print(message.data());
      }
    }
  void getMessages()//(The problem with this is that we need to keep clicking on the onPressed button every single time the new message is sent .So it is not convinient
  async {
    final messages = await _fireStore.collection('messages').get();//to retrieve the data from fire base we are creating a variable message
   messages.docs;//retreive the data from document section under the collection in firestore
    for(var message in messages.docs)//since it is a messages.docs is a list we need to loop through it
       {
        print(message.data());//print the data its messge.data()
     }
  }
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        leading: null,
        actions: <Widget>[
          IconButton(
              icon: Icon(Icons.close),
              onPressed: () {
                messageStream();
                //_auth.signOut();
                //Navigator.pop(context);
                //Implement logout functionality
              }),
        ],
        title: Text('⚡️Chat'),
        backgroundColor: Colors.lightBlueAccent,
      ),
      body: SafeArea(
        child: Column(
          mainAxisAlignment: MainAxisAlignment.spaceBetween,
          crossAxisAlignment: CrossAxisAlignment.stretch,
          children: <Widget>[
            MessagesStream(),
            Container(
              decoration: kMessageContainerDecoration,
              child: Row(
                crossAxisAlignment: CrossAxisAlignment.center,
                children: <Widget>[
                  Expanded(
                    child: TextField(
                      controller:messageTextController,//add a controller to control the textField
                      onChanged: (value) {
                        messageText=value;//Whatever you chat will be stored in the variable String variable messageText
                      },
                      decoration: kMessageTextFieldDecoration,
                    ),
                  ),
                  FlatButton(
                    onPressed: () {
                      messageTextController.clear();
                      _fireStore.collection('messages').add({
                        'text': messageText,//add the messages sent to fireStore under the messages object that we created manually
                        'Sender': loggedInUser.email,//add the current users email to the sender field
                      },);
                    },//goal is to send the data that we type here to the fireStore cloud
                    child: Text(
                      'Send',
                      style: kSendButtonTextStyle,
                    ),
                  ),
                ],
              ),
            ),
          ],
        ),
      ),
    );
  }
}

class MessageBubble extends StatelessWidget {
MessageBubble({required this.sender,required this.text});
  final String sender;
  final String text;
  @override
  Widget build(BuildContext context) {
    return Padding(
      padding: const EdgeInsets.all(10.0),
      child: Column(
        crossAxisAlignment: CrossAxisAlignment.end,
        children: [
          Text(sender,
          style:TextStyle(
            fontSize:12.0,
            color:Colors.black54,
          )
          ),
          Material(
            borderRadius: BorderRadius.circular(20.0),
            elevation: 5.0,
            color:Colors.lightBlueAccent,
            child: Padding(
              padding: const EdgeInsets.symmetric(vertical:10.0,horizontal: 20.0),
              child: Text('$text',
                style:TextStyle(
                  color:Colors.white,
                  fontSize:15,
                ),
              ),
            ),
          ),
        ],
      ),
    );;
  }
}

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

  @override
  Widget build(BuildContext context) {
    return StreamBuilder(
      stream:_fireStore.collection('messages').snapshots(),
      builder: (context, AsyncSnapshot snapshot) {
        if(!snapshot.hasData){//flutters async snapshot contains a query snapshot
          return Center(
            child:CircularProgressIndicator(
              backgroundColor:Colors.lightBlueAccent,
            ),
          );
        }
        final messages = snapshot.data.docs;
        List<MessageBubble> messageBubbles = [];//messageBubbles is of the type MessageBubble
        for(var  message in messages)//Loop through the messages
            {
          final messageText = message.data()['text'];//retrieve the data under the text field in message collection
          final messageSender = message.data()['Sender'];//retrieve the data under the Sender field in message collection
          final messageBubble =MessageBubble(sender: messageSender, text: messageText,);
          messageBubbles.add(messageBubble);//add the text to the List messageWidget
        }
        return ListView(//changed from Column to ListView as we want to scroll down .Or else only finite messages can be fit
          children: messageBubbles,//if u don't write else with a return it will show an error as null returned and null safety broken
        );
      },
    );
  }
}

Solution

Don’t use expanded for TextField. Wrap TextField with SizedBox and explicitly give it a height and width like this,

...
SizedBox(
  width: 200, // a finite number 
  height: 60 // adjust to need
  child: TextField(
    controller:messageTextController,//add a controller to control the textField
    onChanged: (value) {
      messageText=value;//Whatever you chat will be stored in the variable String variable messageText
    },
    decoration: kMessageTextFieldDecoration,
  ),
),
...

Also I notice that you use a ListView, if the above doesn’t work set shrinkWrap as true for the ListView

...
ListView(
  shrinkWrap: true,
  ....
)
...

Answered By – Shaan Mephobic

Answer Checked By – Dawn Plyler (FlutterFixes Volunteer)

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