value_cubit

Description:

value cubit

A dart package that helps to implement basic states for BLoC library to perform, load and fetch data.




Features #

Provides all necessary states for data : init, waiting, value/no value and error states (from value_state),
A ValueCubit class to simplify Cubit subclassing,
A RefreshValueCubit class like ValueCubit with refreshing capabilities,
Some helpers perform (an extension on Cubit) to emit intermediate states while an action is intended to update state : the same state is reemitted with attribute refreshing at true.

Usage #
This example shows how different value states from this library help developpers to show load step data widgets.
class CounterCubit extends ValueCubit<int> {
var _value = 0;

// Put your WS call that can be refreshed
Future<int> _getCounterValueFromWebService() async => _value++;

Future<void> increment() => perform(() async {
// [perform] generate intermediate or final states such as PendingState,
// concrete subclass of ReadyState with right [ReadyState.refreshing] value
// or ErrorState if an error is raised.
final result = await _getCounterValueFromWebService();

emit(ValueState(result));
});

void clear() {
_value = 0;
emit(const PendingState());
}
}

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

@override
Widget build(BuildContext context) {
final theme = Theme.of(context);

return BlocBuilder<CounterCubit, BaseState<int>>(builder: (context, state) {
return Scaffold(
appBar: AppBar(
title: const Text('Flutter Demo Home Page'),
),
body: DefaultTextStyle(
style: const TextStyle(fontSize: 24),
textAlign: TextAlign.center,
child: state is ReadyState<int>
? Column(
crossAxisAlignment: CrossAxisAlignment.stretch,
children: <Widget>[
if (state.refreshing) const LinearProgressIndicator(),
const Spacer(),
if (state.hasError)
Text('Expected error.',
style: TextStyle(color: theme.colorScheme.error)),
if (state is WithValueState<int>) ...[
if (state.hasError)
const Text('Previous counter value :')
else
const Text('Actual counter value :'),
Text(
state.value.toString(),
style: theme.textTheme.headlineMedium,
),
],
if (state is NoValueState<int>) const Text('No Value'),
const Spacer(),
],
)
: const Center(child: CircularProgressIndicator()),
),
floatingActionButton: state is! ReadyState<int>
? null
: FloatingActionButton(
onPressed: state.refreshing
? null
: context.read<CounterCubit>().increment,
tooltip: 'Increment',
child: state.refreshing
? SizedBox.square(
dimension: 20,
child: CircularProgressIndicator(
color: theme.colorScheme.onPrimary))
: const Icon(Icons.refresh)),
);
});
}
}
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The whole code of this example is available in example.
If your cubit is only a getter with the need to refresh your cubit state, you can simplify the implementation ValueCubit with RefreshValueCubit.
class CounterCubit extends RefreshValueCubit<int> {
var _value = 0;

// Put your WS call that can be refreshed
Future<int> _getCounterValueFromWebService() async => _value++;

@override
Future<void> emitValues() async {
final result = await _getCounterValueFromWebService();

emit(ValueState(result));
}
}
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Update your value (increment in our example) by calling myCubit.refresh().
Feedback #
Please file any issues, bugs or feature requests as an issue on the Github page.

License

For personal and professional use. You cannot resell or redistribute these repositories in their original state.

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