Rastreador de hábitos: Eliminar un hábito

Parte de la sección Proyectos del Journey de Flutter de Coddy. Lección 34 de 36.

Los hábitos también terminan. Mantén pulsada una tarjeta para eliminarla. Perder por accidente toda una semana de marcas es mucho, así que la aplicación pregunta primero.

Un InkWell dentro de la tarjeta detecta la pulsación con onLongPress y dibuja la onda. Los círculos de los días conservan sus propios toques: un toque rápido sigue llegando a GestureDetector, y solo una pulsación larga va a la tarjeta.

La pregunta es un diálogo que devuelve true o false, como en la lección anterior. El título indica el nombre del hábito, para que sepas qué estás eliminando:

final delete = await showDialog<bool>(
  context: context,
  builder: (context) => AlertDialog(
    title: Text('Delete ${habit.name}?'),
    ...
  ),
);
if (delete != true) return;

La tarjeta pasa la pulsación larga mediante una tercera devolución de llamada, onLongPress, del mismo modo que pasa los toques en los días.

Desafío

Intermedio

Eliminar hábitos:

escribe Future<void> _deleteHabit(Habit habit) async: un AlertDialog titulado Delete Stretch? (con el nombre del hábito), la línea Its ticks for this week go with it., un Cancel TextButton y un Delete FilledButton; al eliminarlo, quita el hábito
dale a HabitCard un required VoidCallback onLongPress y pasa () => _deleteHabit(habit)
en la tarjeta, coloca un InkWell con ese onLongPress alrededor de Padding y dale a Card clipBehavior: Clip.antiAlias

Pruébalo tú mismo

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.green),
      ),
      home: const HabitScreen(),
    );
  }
}

const List<String> dayNames = ['Mon', 'Tue', 'Wed', 'Thu', 'Fri', 'Sat', 'Sun'];

class Habit {
  Habit(this.name, this.days);

  final String name;
  final List<bool> days;

  int get done => days.where((day) => day).length;

  int get streak {
    int best = 0;
    int run = 0;
    for (bool day in days) {
      if (day) {
        run++;
        if (run > best) best = run;
      } else {
        run = 0;
      }
    }
    return best;
  }
}

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

  @override
  State<HabitScreen> createState() => _HabitScreenState();
}

class _HabitScreenState extends State<HabitScreen> {
  final List<Habit> _habits = [
    Habit('Drink water', [true, true, true, false, true, false, false]),
    Habit('Read 10 pages', [true, false, true, true, false, false, false]),
    Habit('Stretch', List.filled(7, false)),
  ];

  void _toggle(Habit habit, int day) {
    setState(() {
      habit.days[day] = !habit.days[day];
    });
  }

  Future<void> _addHabit() async {
    String name = '';
    final added = await showDialog<bool>(
      context: context,
      builder: (context) => AlertDialog(
        title: const Text('New habit'),
        content: TextField(
          autofocus: true,
          decoration: const InputDecoration(labelText: 'Habit name'),
          onChanged: (value) => name = value,
        ),
        actions: [
          TextButton(
            onPressed: () => Navigator.pop(context, false),
            child: const Text('Cancel'),
          ),
          FilledButton(
            onPressed: () => Navigator.pop(context, true),
            child: const Text('Add'),
          ),
        ],
      ),
    );
    if (added != true || name.trim().isEmpty) return;
    setState(() {
      _habits.add(Habit(name.trim(), List.filled(7, false)));
    });
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(title: const Text('Habits')),
      floatingActionButton: FloatingActionButton(
        onPressed: _addHabit,
        child: const Icon(Icons.add),
      ),
      body: ListView(
        padding: const EdgeInsets.fromLTRB(16, 8, 16, 88),
        children: [
          for (Habit habit in _habits)
            HabitCard(
              habit: habit,
              onToggle: (day) => _toggle(habit, day),
            ),
        ],
      ),
    );
  }
}

class HabitCard extends StatelessWidget {
  const HabitCard({super.key, required this.habit, required this.onToggle});

  final Habit habit;
  final void Function(int day) onToggle;

  @override
  Widget build(BuildContext context) {
    final textTheme = Theme.of(context).textTheme;
    return Card(
      margin: const EdgeInsets.only(top: 12),
      clipBehavior: Clip.antiAlias,
      child: Padding(
        padding: const EdgeInsets.all(16),
        child: Column(
          crossAxisAlignment: CrossAxisAlignment.start,
          children: [
            Row(
              children: [
                Expanded(child: Text(habit.name, style: textTheme.titleMedium)),
                Text('${habit.done} of 7 days', style: textTheme.bodySmall),
              ],
            ),
            const SizedBox(height: 12),
            Row(
              mainAxisAlignment: MainAxisAlignment.spaceBetween,
              children: [
                for (int i = 0; i < 7; i++)
                  DayCircle(
                    label: dayNames[i],
                    done: habit.days[i],
                    onTap: () => onToggle(i),
                  ),
              ],
            ),
            const SizedBox(height: 12),
            Row(
              children: [
                Icon(
                  Icons.local_fire_department,
                  size: 20,
                  color: habit.streak > 0 ? Colors.orange : Theme.of(context).colorScheme.outline,
                ),
                const SizedBox(width: 4),
                Text(habit.streak == 0 ? 'No streak yet' : '${habit.streak} day streak'),
              ],
            ),
          ],
        ),
      ),
    );
  }
}

class DayCircle extends StatelessWidget {
  const DayCircle({super.key, required this.label, required this.done, required this.onTap});

  final String label;
  final bool done;
  final VoidCallback onTap;

  @override
  Widget build(BuildContext context) {
    final colors = Theme.of(context).colorScheme;
    return GestureDetector(
      onTap: onTap,
      child: Container(
        width: 40,
        height: 40,
        alignment: Alignment.center,
        decoration: BoxDecoration(
          shape: BoxShape.circle,
          color: done ? colors.primary : colors.surfaceContainerHighest,
        ),
        child: Text(
          label,
          style: TextStyle(
            fontSize: 11,
            fontWeight: FontWeight.bold,
            color: done ? colors.onPrimary : colors.onSurfaceVariant,
          ),
        ),
      ),
    );
  }
}