rctv 0.1.21

An extremely lightweight library for Flutter state management based on ChangeNotifier, with additional utility classes.

Welcome to the RCTV (ReaCTiVe) package!

rctv is a lightweight solution for abstracting away state management in Flutter.

Features

At the heart of the rctv package is the Reactive class - this provides a simple ChangeNotifier wrapper around any data value, which can then be consumed by the ReactiveProvider or ReactiveListenerWidget widgets.

I personally believe Flutter state management can generally be much simpler than most people think. In the rctv library, reactivity is designed to come from two main sources:

1. Data model classes, such as User can be cached in a ReactiveManager, will turn them into Reactive objects.
2. Page ViewModels - these should inherit from ReactiveAggregate, and define particular Reactive properties to which the appropriate segments of the page UI will respond.

Both of these cases are dead simple to set up, and wherever you want to use a reactive value you can simply access it through a ReactiveProvider widget.

This library supports both Reactive and ReactiveStream objects, which behave similarly but are designed to give you a bit more control over how you prefer to write state data.

Getting started

To install, run flutter pub add rctv.

Usage

class CounterPageViewModel extends ReactiveAggregate {

    final counter = Reactive(0);

    void increment() {
        counter.set(counter.value + 1);
    }

    @override
    void dispose() {
        disposeReactives([ counter ]);
    }

}

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

  @override
  State<CounterPage> createState() => _CounterPageState();
}

class _CounterPageState extends State<CounterPage> {

  final viewModel = CounterPageViewModel();

  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'RCTV Demo',
      theme: ThemeData(
        primarySwatch: Colors.blue,
      ),
      home: Scaffold(
        appBar: AppBar(
            title: Text('Counter demo'),
        ),
        body: Center(
            child: Column(
                mainAxisAlignment: MainAxisAlignment.center,
                children: <Widget>[
                    Text(
                    'You have pushed the button this many times:',
                    ),
                    ReactiveProvider(
                        viewModel.counter,
                        builder: (context, value) => Text('$value', style: Theme.of(context).textTheme.display1)
                    ),
                ],
            ),
        ),
        floatingActionButton: FloatingActionButton(
            onPressed: viewModel.increment,
            tooltip: 'Increment',
            child: Icon(Icons.add),
        )
      )
    );
  }
}

Additional information

Another important class included in this package is the Loadable, a further wrapper for Reactive that provides a scaffold for asynchronous request handling.

If desired, rctv also supports creating SupervisedReactive objects, which update according to defined transactions, allowing them to be observed via a ReactiveSupervisor (or ReactiveSupervisorProvider) similar to observer patterns in other state management libraries like BLoC.