The following assertion was thrown while dispatching notifications for CV: setState() or markNeedsBu-CodePudding

I used the Provider to take the value from the Text Form Field and store it via the Provider but I am getting an error that I could not solve at all. And this code

Code of text_field

import 'dart:ffi';
import 'dart:ui';

import 'package:flutter/material.dart';

Widget text_field( {
  required TextEditingController TextEditing_Controller,
  required bool obscure_Text,
  required TextInputType keyboardType,
  required bool auto_focus,
  required bool This_Suffix,
  required String prefix_Text,
  required   on_changed,
  suffix_Icon,})
//------------------------------------
{
  return Container(
    //---------------------------
    decoration: BoxDecoration(
            color: Colors.white,
             border: Border(
              top: BorderSide(color: Colors.red),
              bottom: BorderSide(color: Colors.red),
            ),
          ),
    //-------------------------------
    width: 300,
    height: 50,
    child:TextFormField(
          style: TextStyle(
          color: Colors.blue,
          fontSize: 15,

      ),
      //----------------------------------
      onChanged: on_changed,
      controller: TextEditing_Controller,
      obscureText:obscure_Text,
      keyboardType:keyboardType ,
      //----------------------------------
      validator: (value) {
        if (value == null || value.isEmpty) {
          return 'Please enter some text';
        }
        return null;
      },
      //-----------------------------------

      decoration: InputDecoration(
        border: InputBorder.none,
          hintText: prefix_Text,

        hintStyle: TextStyle(

            color: Colors.blue,
              fontSize: 15,
            fontWeight: FontWeight.bold
          ),
          fillColor: Colors.white.withOpacity(0.5),
          filled: true,
        hoverColor: Colors.deepPurpleAccent.withOpacity(0.5),

        //-----------------------------------

    ),
  ));
}

Code of main This is the main.dart file and from it I called the CV Provider using multiprovider

void main() {
  runApp(MultiProvider(
    providers: [
      ChangeNotifierProvider(
        create: (BuildContext context) => CV(),
      ),
    ],
    child: MyApp(),
  ));
}

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      debugShowCheckedModeBanner: false,
      theme: ThemeData(
        appBarTheme: AppBarTheme(
          color: Colors.purpleAccent,
          iconTheme: IconThemeData(color: Colors.red),
          actionsIconTheme: IconThemeData(color: Colors.amber),
          centerTitle: false,
          elevation: 15,
          // backgroundColor:Colors.lightBlue
          titleTextStyle: TextStyle(color: Colors.lightBlueAccent),
        ),
        primarySwatch: Colors.blue,
      ),
      home: homeScreen(),
    );
  }
}

code CVChangeNotifier

This is the CV file that inherited from ChangeNotifire and in which I defined the variables and functions that I used in the form


class CV with ChangeNotifier {
  List Skills = [];
  var _your_fullname,
      _skill,
      _your_email,
      _your_location,
      _your_nameuniversiy,
      _your_GPA,
      _your_number,
      _project;
  List projects = [];
  //----------------------------------------
  get Skill => _skill;
  addSkill(Skill) {
    _skill = Skill;
    Skills.add(_skill);
    notifyListeners();
  }

  //****************************
  get Project => _project;
  addproject(Project) {
    _project = Project;
    Skills.add(_project);
    notifyListeners();
  }

  //****************************
  get fullname => _your_fullname;

  addFullname(fullname) {
    _your_fullname = fullname;
    notifyListeners();
  }

  //-----------------------------
  get email => _your_fullname;

  addEmail(email) {
    _your_email = email;
    notifyListeners();
  }

  //-----------------------------
  get location => _your_location;
  addlocation(location) {
    _your_location = location;
    notifyListeners();
  }

  //-----------------------------
  get nameuniversiy => _your_nameuniversiy;
  addnameuniversiy(nameuniversiy) {
    _your_nameuniversiy = nameuniversiy;
    notifyListeners();
  }

  //-----------------------------
  get number => _your_number;
  addnnumber(number) {
    _your_number = number;
    notifyListeners();
  }

  //-----------------------------
  get GPA => _your_GPA;
  addGPA(GPA) {
    _your_GPA = GPA;
    notifyListeners();
  }
//-----------------------------
}

code of homescreen Here I made a screen to enter information and used initState and knew an object from the Provider

class homeScreen extends StatefulWidget {
  @override
  State<homeScreen> createState() => _homeScreenState();
}

//==============================================
class _homeScreenState extends State<homeScreen> {
  //==============================================
  final _formKey = GlobalKey<FormState>();
  late TextEditingController _nameController,
      _emailController,
      _numberController,
      _locationController,
      _universitnameController,
      _GPAController,
      _projectController,
      _SkillController;
  late CV MyCV;
  //==============================================
  @override
  void initState() {
    //==============================================
    Future.delayed(Duration.zero, () {
      MyCV = Provider.of<CV>(context, listen: false);

      super.initState();
      _nameController = TextEditingController(text: MyCV.fullname);
      _emailController = TextEditingController(text: MyCV.email);
      _numberController = TextEditingController(text: MyCV.number);
      _locationController = TextEditingController(text: MyCV.location);
      _universitnameController =
          TextEditingController(text: MyCV.nameuniversiy);
      _GPAController = TextEditingController(text: MyCV.GPA);
      _projectController = TextEditingController(text: MyCV.Project);
      _SkillController = TextEditingController(text: MyCV.Skill);
      //==============================================
    });
  }

  @override
  void dispose() {
    //==============================================
    _nameController.dispose();
    _emailController.dispose();
    _numberController.dispose();
    _locationController.dispose();
    _universitnameController.dispose();
    _GPAController.dispose();
    _projectController.dispose();
    _SkillController.dispose();
    //==============================================
    super.dispose();
  }

  @override
  Widget build(BuildContext context) {
    //==============================================
    return Scaffold(
      body: SafeArea(
        child: Container(
          color: Colors.black12,
          width: double.infinity,
          height: double.infinity,
          child: Column(
            children: [
              Container(
                width: double.infinity,
                height: 90,
                child: Row(
                  mainAxisAlignment: MainAxisAlignment.center,
                  children: [
                    Container(
                        decoration: BoxDecoration(
                      border: Border.all(color: Colors.red, width: 6),
                      shape: BoxShape.circle,
                    )),
                    Container(
                      height: 2,
                      width: 90,
                      color: Colors.red,
                    ),
                    SizedBox(
                      width: 5,
                    ),
                    Text(
                      'Personal Info',
                      style: TextStyle(
                          color: Colors.blue,
                          fontSize: 20,
                          fontWeight: FontWeight.bold),
                    ),
                    SizedBox(
                      width: 5,
                    ),
                    Container(
                      height: 2,
                      width: 90,
                      color: Colors.red,
                    ),
                    Container(
                        decoration: BoxDecoration(
                      border: Border.all(color: Colors.red, width: 6),
                      shape: BoxShape.circle,
                    )),
                  ],
                ),
              ),
              SizedBox(
                height: 10,
              ),
              text_field(
                  obscure_Text: false,
                  prefix_Text: 'Your name:',
                  TextEditing_Controller: _nameController,
                  on_changed: MyCV.addFullname(_nameController.text),
                  This_Suffix: false,
                  auto_focus: true,
                  keyboardType: TextInputType.text),
              SizedBox(
                height: 10,
              ),
              text_field(
                  obscure_Text: false,
                  prefix_Text: 'Your Email:',
                  TextEditing_Controller: _emailController,
                  on_changed: MyCV.addEmail(_emailController.text),
                  This_Suffix: false,
                  auto_focus: true,
                  keyboardType: TextInputType.emailAddress),
              SizedBox(
                height: 10,
              ),
              text_field(
                  obscure_Text: false,
                  prefix_Text: 'Your name of University:',
                  TextEditing_Controller: _universitnameController,
                  on_changed:
                      MyCV.addnameuniversiy(_universitnameController.text),
                  This_Suffix: false,
                  auto_focus: true,
                  keyboardType: TextInputType.text),
              SizedBox(
                height: 10,
              ),
              text_field(
                  obscure_Text: false,
                  prefix_Text: 'Your Location:',
                  TextEditing_Controller: _locationController,
                  on_changed: MyCV.addlocation(_locationController.text),
                  This_Suffix: false,
                  auto_focus: true,
                  keyboardType: TextInputType.number),
              SizedBox(
                height: 10,
              ),
              text_field(
                  obscure_Text: false,
                  prefix_Text: 'Your GPA:',
                  TextEditing_Controller: _GPAController,
                  on_changed: MyCV.addnameuniversiy(_GPAController.text),
                  This_Suffix: false,
                  auto_focus: true,
                  keyboardType: TextInputType.text),
            ],
          ),
        ),
      ),
    );
  }
}

CodePudding user response：

It is better to use addPostFrameCallback to get context after 1st build.

The issue is here you are passing super.initState(); inside your future delay.

Also For

Follow this way There are controllers are null first build.

  TextEditingController _nameController = TextEditingController();
 //... others are same
  CV? MyCV;

  @override
  void initState() {
    super.initState();
    WidgetsBinding.instance.addPostFrameCallback((timeStamp) {
      MyCV = Provider.of<CV>(context, listen: false);
       _nameController.text = MyCV?.fullname ?? "";
     //... others are same
    });
  }

 on_changed: MyCV?.addFullname(_nameController.text),