import 'package:flutter/material.dart';

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

class TodoApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return new MaterialApp(title: 'Todo List', home: new TodoList());
  }
}

class TodoList extends StatefulWidget {
  @override
  createState() => new TodoListState();
}

class TodoListState extends State<TodoList>
{
  List<String> _todoItems = [];

  void _addTodoItem()
  {
    setState(()
    {
      int index = _todoItems.length;
      _todoItems.add('Item ' + index.toString());
    });
  }

  Widget _buildTodoList()
  {
    return new ListView.builder
    (
      itemBuilder: (context, index)
      {
        if (index < _todoItems.length)
        {
          return _buildTodoItem(_todoItems[index]);
        }
      },
    );
  }

  Widget _buildTodoItem(String todoText)
  {
    return new ListTile(title: new Text(todoText));
  }

  @override
  Widget build(BuildContext context)
  {
    return new Scaffold
    (
      appBar: new AppBar(title: new Text('Todo List')),
      body: _buildTodoList(),
      floatingActionButton: new FloatingActionButton
      (
          onPressed: _addTodoItem,
          tooltip: 'Add task',
          child: new Icon(Icons.add)),
    );
  }
}