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Pelacak Kebiasaan: Terang dan Gelap

Termasuk bagian Proyek dalam perjalanan Flutter di Coddy. Pelajaran 36 dari 36.

Orang sering memeriksa kebiasaan larut malam, jadi fitur terakhirnya adalah mode gelap, dengan tombol di bilah atas: ikon bulan untuk menyalakannya, ikon matahari untuk mengembalikannya.

Tema berada di MaterialApp, jadi pengalihnya juga ada di sana: MyApp menjadi StatefulWidget dengan bool _dark. MaterialApp menerima kedua tema dan memilih salah satunya dengan themeMode:

darkTheme: ThemeData(
  colorScheme: ColorScheme.fromSeed(
    seedColor: Colors.green,
    brightness: Brightness.dark,
  ),
),
themeMode: _dark ? ThemeMode.dark : ThemeMode.light,

Tombolnya ada di layar kebiasaan, jauh di bawah MyApp. Naikkan state sekali lagi: HabitScreen menerima dark untuk memilih ikonnya dan callback onToggleTheme untuk dipanggil. Layar membaca keduanya dari widget-nya sebagai widget.dark dan widget.onToggleTheme.

Semua warna di aplikasi berasal dari tema, jadi kartu, lingkaran, dan cincin semuanya ikut berganti. Kebiasaanmu tetap tercentang karena berada di state layar, bukan di tema.

Ini pelajaran terakhir dari proyek-proyek kursus. Pemeriksaan menggunakan seluruh pelacak: tambah, centang, rangkaian, hapus, cincin, dan mode gelap.

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Tantangan

Sulit

Tambahkan mode gelap:

  • jadikan MyApp sebagai StatefulWidget dengan bool _dark = false, berikan MaterialApp sebuah darkTheme dari seed hijau yang sama dengan Brightness.dark, lalu atur themeMode berdasarkan _dark
  • berikan HabitScreen required bool dark dan VoidCallback onToggleTheme; MyApp meneruskan _dark dan sebuah fungsi yang membalik nilainya di dalam setState
  • di dalam actions pada bilah atas, sebuah IconButton menampilkan Icons.dark_mode dalam mode terang dan Icons.light_mode dalam mode gelap, serta memanggil widget.onToggleTheme

Coba sendiri

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)),
  ];

  int get _ticks => _habits.fold(0, (sum, habit) => sum + habit.done);
  int get _possible => _habits.length * 7;

  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)));
    });
  }

  Future<void> _deleteHabit(Habit habit) async {
    final delete = await showDialog<bool>(
      context: context,
      builder: (context) => AlertDialog(
        title: Text('Delete ${habit.name}?'),
        content: const Text('Its ticks for this week go with it.'),
        actions: [
          TextButton(
            onPressed: () => Navigator.pop(context, false),
            child: const Text('Cancel'),
          ),
          FilledButton(
            onPressed: () => Navigator.pop(context, true),
            child: const Text('Delete'),
          ),
        ],
      ),
    );
    if (delete != true) return;
    setState(() {
      _habits.remove(habit);
    });
  }

  @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: [
          ProgressCard(ticks: _ticks, possible: _possible),
          for (Habit habit in _habits)
            HabitCard(
              habit: habit,
              onToggle: (day) => _toggle(habit, day),
              onLongPress: () => _deleteHabit(habit),
            ),
        ],
      ),
    );
  }
}

class ProgressCard extends StatelessWidget {
  const ProgressCard({super.key, required this.ticks, required this.possible});

  final int ticks;
  final int possible;

  @override
  Widget build(BuildContext context) {
    final colors = Theme.of(context).colorScheme;
    final textTheme = Theme.of(context).textTheme;
    final progress = possible == 0 ? 0.0 : ticks / possible;
    return Card(
      margin: EdgeInsets.zero,
      color: colors.primaryContainer,
      child: Padding(
        padding: const EdgeInsets.all(20),
        child: Row(
          children: [
            SizedBox(
              width: 72,
              height: 72,
              child: Stack(
                fit: StackFit.expand,
                children: [
                  CircularProgressIndicator(
                    value: progress,
                    strokeWidth: 8,
                    strokeCap: StrokeCap.round,
                    backgroundColor: colors.surface,
                  ),
                  Center(
                    child: Text(
                      '${(progress * 100).round()}%',
                      style: textTheme.titleMedium?.copyWith(fontWeight: FontWeight.bold),
                    ),
                  ),
                ],
              ),
            ),
            const SizedBox(width: 20),
            Expanded(
              child: Column(
                crossAxisAlignment: CrossAxisAlignment.start,
                children: [
                  Text('This week', style: textTheme.titleLarge),
                  const SizedBox(height: 4),
                  Text('$ticks of $possible ticks'),
                ],
              ),
            ),
          ],
        ),
      ),
    );
  }
}

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

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

  @override
  Widget build(BuildContext context) {
    final textTheme = Theme.of(context).textTheme;
    return Card(
      margin: const EdgeInsets.only(top: 12),
      clipBehavior: Clip.antiAlias,
      child: InkWell(
        onLongPress: onLongPress,
        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,
          ),
        ),
      ),
    );
  }
}
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