main.dart

/// imports widgets from the material design 
import 'package:flutter/material.dart';

void main() => runApp(TodoApp());

/// Stateless widgets must implement the build() method and return a widget. 
/// The first parameter passed to build function is the context in which this widget is built
class TodoApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'TODO',
      theme: ThemeData(
        primarySwatch: Colors.blue,
      ),
      home: TodoList(),
    );
  }
}

/// Stateful widgets must implement the createState method
/// State of a stateless widget against has a build() method with context
class TodoList extends StatefulWidget {
  @override
  State<StatefulWidget> createState() => TodoListState();
}

class TodoListState extends State<TodoList> {
  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text('Todo'),
      ),
      body: Text('Todo List'),
    );
  }
}