Named parameter required, but there's no corresponding argument. What should I do?

Question

I've been getting the following related errors at my Flutter application:

The named parameter 'description' is required, but there's no corresponding argument. Try adding the required argument.

The named parameter 'id' is required, but there's no corresponding argument. Try adding the required argument.

I am receiving this errors at:

Task _newTask = Task(title: value);

Here is my taskpage.dart

    // ignore_for_file: prefer_const_constructors

import 'package:flutter/material.dart';
import 'package:flutter_to_do/database_helper.dart';
import 'package:flutter_to_do/models/task.dart';
import 'package:flutter_to_do/models/todo.dart';
import 'package:flutter_to_do/widgets.dart';

class Taskpage extends StatefulWidget {
  final Task task;

  Taskpage({required this.task});

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

class _TaskpageState extends State<Taskpage> {
  DatabaseHelper _dbHelper = DatabaseHelper();

  int _taskId = 0;
  String _taskTitle = "";
  String _taskDescription = "";

  late FocusNode _titleFocus;
  late FocusNode _descriptionFocus;
  late FocusNode _todoFocus;

  bool _contentVisile = false;

  @override
  void initState() {
    if (widget.task != null) {
      // Set visibility to true
      _contentVisile = true;

      _taskTitle = widget.task.title;
      _taskDescription = widget.task.description;
      _taskId = widget.task.id;
    }

    _titleFocus = FocusNode();
    _descriptionFocus = FocusNode();
    _todoFocus = FocusNode();

    super.initState();
  }

  @override
  void dispose() {
    _titleFocus.dispose();
    _descriptionFocus.dispose();
    _todoFocus.dispose();

    super.dispose();
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      body: SafeArea(
        child: Container(
          child: Stack(
            children: [
              Column(
                crossAxisAlignment: CrossAxisAlignment.start,
                children: [
                  Padding(
                    padding: EdgeInsets.only(
                      top: 24.0,
                      bottom: 6.0,
                    ),
                    child: Row(
                      children: [
                        InkWell(
                          onTap: () {
                            Navigator.pop(context);
                          },
                          child: Padding(
                            padding: const EdgeInsets.all(24.0),
                            child: Image(
                              image: AssetImage(
                                  'assets/images/back_arrow_icon.png'),
                            ),
                          ),
                        ),
                        Expanded(
                          child: TextField(
                            focusNode: _titleFocus,
                            onSubmitted: (value) async {
                              // Check if the field is not empty
                              if (value != "") {
                                // Check if the task is null
                                if (widget.task == null) {
                                  Task _newTask = Task(title: value);
                                  _taskId =
                                      await _dbHelper.insertTask(_newTask);
                                  setState(() {
                                    _contentVisile = true;
                                    _taskTitle = value;
                                  });
                                } else {
                                  await _dbHelper.updateTaskTitle(
                                      _taskId, value);
                                  print("Task Updated");
                                }
                                _descriptionFocus.requestFocus();
                              }
                            },
                            controller: TextEditingController()
                              ..text = _taskTitle,
                            // ignore: prefer_const_constructors
                            decoration: InputDecoration(
                              hintText: "Enter Task Title",
                              border: InputBorder.none,
                            ),
                            style: TextStyle(
                              fontSize: 26.0,
                              fontWeight: FontWeight.bold,
                              color: Color(0xFF211551),
                            ),
                          ),
                        )
                      ],
                    ),
                  ),
                  Visibility(
                    visible: _contentVisile,
                    child: Padding(
                      padding: EdgeInsets.only(
                        bottom: 12.0,
                      ),
                      child: TextField(
                        focusNode: _descriptionFocus,
                        onSubmitted: (value) async {
                          if (value != "") {
                            if (_taskId != 0) {
                              await _dbHelper.updateTaskDescription(
                                  _taskId, value);
                              _taskDescription = value;
                            }
                          }
                          _todoFocus.requestFocus();
                        },
                        controller: TextEditingController()
                          ..text = _taskDescription,
                        decoration: InputDecoration(
                          hintText: "Enter Description for the task...",
                          border: InputBorder.none,
                          contentPadding: EdgeInsets.symmetric(
                            horizontal: 24.0,
                          ),
                        ),
                      ),
                    ),
                  ),
                  Visibility(
                    visible: _contentVisile,
                    child: FutureBuilder(
                      initialData: [],
                      future: _dbHelper.getTodo(_taskId),
                      builder: (context, AsyncSnapshot snapshot) {
                        return Expanded(
                          child: ListView.builder(
                            itemCount: snapshot.data.length,
                            itemBuilder: (context, index) {
                              return GestureDetector(
                                onTap: () async {
                                  if (snapshot.data[index].isDone == 0) {
                                    await _dbHelper.updateTodoDone(
                                        snapshot.data[index].id, 1);
                                  } else {
                                    await _dbHelper.updateTodoDone(
                                        snapshot.data[index].id, 0);
                                  }
                                  setState(() {});
                                },
                                child: TodoWidget(
                                  text: snapshot.data[index].title,
                                  isDone: snapshot.data[index].isDone == 0
                                      ? false
                                      : true,
                                ),
                              );
                            },
                          ),
                        );
                      },
                    ),
                  ),
                  Visibility(
                    visible: _contentVisile,
                    child: Padding(
                      padding: EdgeInsets.symmetric(
                        horizontal: 24.0,
                      ),
                      child: Row(
                        children: [
                          Container(
                            width: 20.0,
                            height: 20.0,
                            margin: EdgeInsets.only(
                              right: 12.0,
                            ),
                            decoration: BoxDecoration(
                                color: Colors.transparent,
                                borderRadius: BorderRadius.circular(6.0),
                                border: Border.all(
                                    color: Color(0xFF86829D), width: 1.5)),
                            child: Image(
                              image: AssetImage('assets/images/check_icon.png'),
                            ),
                          ),
                          Expanded(
                            child: TextField(
                              focusNode: _todoFocus,
                              controller: TextEditingController()..text = "",
                              onSubmitted: (value) async {
                                // Check if the field is not empty
                                if (value != "") {
                                  if (_taskId != 0) {
                                    DatabaseHelper _dbHelper = DatabaseHelper();
                                    Todo _newTodo = Todo(
                                      title: value,
                                      isDone: 0,
                                      taskId: _taskId,
                                    );
                                    await _dbHelper.insertTodo(_newTodo);
                                    setState(() {});
                                    _todoFocus.requestFocus();
                                  } else {
                                    print("Task doesn't exist");
                                  }
                                }
                              },
                              decoration: InputDecoration(
                                hintText: "Enter Todo item...",
                                border: InputBorder.none,
                              ),
                            ),
                          ),
                        ],
                      ),
                    ),
                  )
                ],
              ),
              Visibility(
                visible: _contentVisile,
                child: Positioned(
                  bottom: 24.0,
                  right: 24.0,
                  child: GestureDetector(
                    onTap: () async {
                      if (_taskId != 0) {
                        await _dbHelper.deleteTask(_taskId);
                        Navigator.pop(context);
                      }
                    },
                    child: Container(
                      width: 60.0,
                      height: 60.0,
                      decoration: BoxDecoration(
                        color: Color(0xFFFE3577),
                        borderRadius: BorderRadius.circular(20.0),
                      ),
                      child: Image(
                        image: AssetImage(
                          "assets/images/delete_icon.png",
                        ),
                      ),
                    ),
                  ),
                ),
              )
            ],
          ),
        ),
      ),
    );
  }
}

here it is my task.dart

class Task {
  final int id;
  final String title;
  final String description;
  Task({required this.id, required this.title, required this.description});

  Map<String, dynamic> toMap() {
    return {
      'id': id,
      'title': title,
      'description': description,
    };
  }
}

What can I do to solve this issue? I tried to use

final String? description

and remove the required command, but it gave different errors.

Answer 1

Either you can make description nullable and not required as you already tried:

final String? description;
Task({required this.id, required this.title, this.description});

or specify a default value instead of the required:

final String description;
Task({required this.id, required this.title, this.description = ''});

Any other errors that may be thrown are probably related to you not expecting description to be nullable.