To-do List: Tick It Done

Part of the Projects section of Coddy's Flutter journey. Lesson 3 of 36.

A task needs to remember whether it is done. Give the class a second field that starts as false and can change, so it is not final:

class Task {
  Task(this.title);

  final String title;
  bool done = false;
}

Each row gets a Checkbox as its leading: widget. Its value is the task's done, and its onChanged sets done inside setState.

A done task should look done. TextDecoration.lineThrough draws a line through the text, and a grey color makes it step back. When the task is not done, the style is null and the text keeps the theme's look:

style: task.done
    ? const TextStyle(decoration: TextDecoration.lineThrough, color: Colors.grey)
    : null,

Challenge

Medium

Tick tasks done:

add bool done = false; to Task
give each ListTile a leading: Checkbox that shows and changes the task's done
when a task is done, cross its title out and make it Colors.grey

Try it yourself

import 'package:flutter/material.dart';

void main() {
  runApp(const MyApp());
}

class MyApp extends StatelessWidget {
  const MyApp({super.key});

  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      debugShowCheckedModeBanner: false,
      theme: ThemeData(
        colorScheme: ColorScheme.fromSeed(seedColor: Colors.teal),
      ),
      home: const TodoScreen(),
    );
  }
}

class Task {
  Task(this.title);

  final String title;
}

class TodoScreen extends StatefulWidget {
  const TodoScreen({super.key});

  @override
  State<TodoScreen> createState() => _TodoScreenState();
}

class _TodoScreenState extends State<TodoScreen> {
  final List<Task> _tasks = [Task('Buy milk'), Task('Walk the dog'), Task('Read a book')];
  final _controller = TextEditingController();

  void _addTask() {
    setState(() {
      _tasks.add(Task(_controller.text));
    });
    _controller.clear();
  }

  @override
  void dispose() {
    _controller.dispose();
    super.dispose();
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(title: const Text('My Tasks')),
      body: Column(
        children: [
          Padding(
            padding: const EdgeInsets.fromLTRB(16, 16, 16, 8),
            child: Row(
              children: [
                Expanded(
                  child: TextField(
                    controller: _controller,
                    decoration: const InputDecoration(
                      labelText: 'New task',
                      border: OutlineInputBorder(),
                    ),
                  ),
                ),
                const SizedBox(width: 8),
                IconButton.filled(
                  onPressed: _addTask,
                  icon: const Icon(Icons.add),
                ),
              ],
            ),
          ),
          Expanded(
            child: ListView.builder(
              itemCount: _tasks.length,
              itemBuilder: (context, index) {
                final task = _tasks[index];
                return ListTile(
                  title: Text(task.title),
                );
              },
            ),
          ),
        ],
      ),
    );
  }
}