Flutter Provider #

dependencies:
  provider: ^6.1.1

class Counter extends ChangeNotifier {
  int _count = 0;
  
  int get count => _count;
  
  void increment() {
    _count++;
    notifyListeners();
  }
}

void main() {
  runApp(
    ChangeNotifierProvider(
      create: (_) => Counter(),
      child: MyApp(),
    ),
  );
}

Provider<String>(
  create: (_) => 'Hello',
  child: Text(context.read<String>()),
)

ChangeNotifierProvider(
  create: (_) => Counter(),
  child: MyApp(),
)

MultiProvider(
  providers: [
    ChangeNotifierProvider(create: (_) => Counter()),
    ChangeNotifierProvider(create: (_) => User()),
  ],
  child: MyApp(),
)

Text('${context.watch<Counter>().count}')

ElevatedButton(
  onPressed: () => context.read<Counter>().increment(),
  child: Text('Add'),
)

Consumer<Counter>(
  builder: (context, counter, child) {
    return Text('${counter.count}');
  },
)

Selector<Counter, int>(
  selector: (_, counter) => counter.count,
  builder: (context, count, child) {
    return Text('$count');
  },
)