Cubit Template

1
import 'package:flutter_bloc/flutter_bloc.dart';
2
 
3
// States
4
sealed class CounterState {}
5
class CounterInitial extends CounterState {}
6
class CounterLoading extends CounterState {}
7
class CounterLoaded extends CounterState {
8
  final int count;
9
  CounterLoaded(this.count);
10
}
11
class CounterError extends CounterState {
12
  final String message;
13
  CounterError(this.message);
14
}
15
 
16
// Cubit
17
class CounterCubit extends Cubit<CounterState> {
18
  CounterCubit() : super(CounterInitial());
19
 
20
  void increment() {
21
    final current = state;
22
    if (current is CounterLoaded) {
23
      emit(CounterLoaded(current.count + 1));
24
    }
25
  }
26
 
27
  Future<void> load() async {
28
    emit(CounterLoading());
29
    try {
30
      await Future.delayed(const Duration(seconds: 1));
31
      emit(CounterLoaded(0));
32
    } catch (e) {
33
      emit(CounterError(e.toString()));
34
    }
35
  }
36
}
37
 
38
// Usage in widget
39
class CounterPage extends StatelessWidget {
40
  const CounterPage({super.key});
41
 
42
  @override
43
  Widget build(BuildContext context) {
44
    return BlocProvider(
45
      create: (_) => CounterCubit()..load(),
46
      child: BlocBuilder<CounterCubit, CounterState>(
47
        builder: (context, state) {
48
          return switch (state) {
49
            CounterInitial() => const CircularProgressIndicator(),
50
            CounterLoading() => const CircularProgressIndicator(),
51
            CounterLoaded(:final count) => Text('Count: $count'),
52
            CounterError(:final message) => Text('Error: $message'),
53
          };
54
        },
55
      ),
56
    );
57
  }
58
}