minimals_state_manager 0.0.1-alpha.0.0.1

The minimals_state_manager package is a study project on state management, observables, lifecycle, and best practices for Flutter applications. It provides a minimalist implementation of state managem [...]

The minimals_state_manager package is a minimalist implementation of state management for Flutter apps, using only native Flutter packages. The goal is to simplify the process of managing states in your projects by providing an easy-to-use framework that takes full advantage of Flutter's native functionality.

For this, the package uses important packages such as InheritedWidget, ChangeNotifier, ValueNotifier, ValueNotifierBuilder and WidgetsBindingObserver to control the lifecycle of the application in its controllers.

With minimals_state_manager, you will have a minimal state management implementation that is easy to understand and that speeds up Flutter application development. However, it is important to point out that this package is intended for study about state management, observables, lifecycle and best practices only and is not recommended for production as it is still in alpha version.

Features

Embora ainda esteja em sua versão alpha, este gerenciador de estados já possui as seguintes características:

- MinProvider and MinMultiProvider are state management providers that allow you to easily manage and share the state of your Flutter application between different components. MinProvider is used for single state management, while MinMultiProvider is used for managing multiple states in a single provider. By using MinProvider and MinMultiProvider, you can simplify the process of managing state and reduce boilerplate code in your Flutter projects.  

```dart
MinProvider(
  controller: YourController(),
  child: YourPage()
)
```

or

```dart
MinMultiProvider(
  controllers: [YourController1(), YourController2()],
  child: YourPage()
)
```

- Observable widget $(), this is a generic observable widget that can be used to listen for changes to a value notifier and update the UI accordingly. It takes in a value notifier and a builder function that defines how the UI should be updated based on the current value of the notifier. This widget is useful for cases where you want to decouple the UI from the data source, allowing for changes in the data to automatically update the UI without having to manually manage state. It can be used in a variety of scenarios such as form input fields, status indicators, or progress bars.  

```dart
$(
  (count) => Text('Count $count'), // function returns real value as int
  listener: controller.count // count is ValueNotifier<int> 
)
```

- MinController, this class is an abstraction for creating state controllers that use Flutter's ChangeNotifier class and implement the WidgetsBindingObserver mixin. This allows controllers to react to changes in the application lifecycle, as well as notify observers when state changes occur. The class has methods to handle application lifecycle and other startup and shutdown operations. It is useful for creating reactive and observable controllers that can be used throughout an application.  

```dart
class YourController extends MinController {
  @override
  void onInit() {
    print('init controller');
    super.onInit();
  }

  final count = 0.minx;
  ValueNotifier<User> user = User().minx;

  increment() => count.value++;
  decrement() => count.value--;
  refresh() => count.value = 0;

  onChangedName(str) => user.update((val) => val.name = str);
  onSaveName(str) => user.update((val) => val.name = str);
  validateName(str) => str.length < 2 ? 'insert valid name' : null;
}

class User {
  User({this.name});
  String? name;
}

```

- MinX<Controller> MinX is a widget that provides a generic way to obtain a MinController and rebuild the widget tree when the controller's state changes. It uses the MinProvider and MinMultiProvider classes to retrieve the controller from the widget tree, depending on its type. The controller is then passed to a builder function that returns the widget tree to be built.  

```dart
MinX<YourController>(
  builder: (context, controller) => Text(controller.name)
)

```

Getting started

$ flutter pub add minimals_state_manager

or add in your dependencies

dependencies:
  minimals_state_manager: <latest>

Usage

This is simple example, for a more complete and complex, see the /example folder.

In your main.dart

Use the MinProvider() widget to provide a Controller for the child widget tree. If you need more than one Controller, you can use MinMultiProvider() to pass a list of controllers.

void main() {
  runApp(
    MaterialApp(
      home: MinProvider(
        controller: MyController(), 
        child: const MyPage(),
      ),
    ),
  );
}

Use MinX<YourController>() widget to retrieve the available controller instance to use its methods and attributes in certain parts of the code.

Use the observable widget $() to listen for updates to your controller's observable variable, this widget expects a ValueNotifier type listener, and has a function that returns the real value of the object passed, updating whenever necessary.

class MyPage extends StatelessWidget {
  final GlobalKey<FormState> formKey = GlobalKey<FormState>();
  const MyPage({super.key});

  @override
  Widget build(BuildContext context) => Scaffold(
        floatingActionButtonLocation: FloatingActionButtonLocation.endFloat,
        floatingActionButton: MinX<MyController>(
          builder: (context, controller) => Column(
            mainAxisAlignment: MainAxisAlignment.end,
            children: [
              FloatingActionButton(
                backgroundColor: Colors.lightGreen,
                onPressed: () => controller.increment(),
                child: const Icon(Icons.add),
              ),
              const SizedBox(
                height: 16.0,
              ),
              FloatingActionButton(
                backgroundColor: Colors.redAccent,
                onPressed: () => controller.decrement(),
                child: const Icon(Icons.remove),
              ),
              const SizedBox(
                height: 16.0,
              ),
              FloatingActionButton(
                onPressed: () => controller.refresh(),
                child: const Icon(Icons.refresh),
              ),
            ],
          ),
        ),
        body: SafeArea(
          child: Column(
            mainAxisAlignment: MainAxisAlignment.center,
            children: [
              const Text('check out the full example in the example folder'),
                Container(
                margin: const EdgeInsets.only(
                    left: 32.0, right: 32.0, bottom: 32.0),
                child: Form(
                  key: formKey,
                  child: MinX<MyController>(
                    builder: (context, controller) => TextFormField(
                      onChanged: (value) => controller.onChangedName(value),
                      validator: (value) => controller.validateName(value),
                      onSaved: (newValue) => controller.onSaveName(newValue),
                    ),
                  ),
                ),
              ),
              Column(
                mainAxisAlignment: MainAxisAlignment.center,
                children: [
                  Row(
                    mainAxisAlignment: MainAxisAlignment.center,
                    children: [
                      MinX<MyController>(
                        builder: (context, controller) => $(
                          (count) => Text(
                            'Count $count',
                            style: const TextStyle(
                              fontSize: 24.0,
                              fontWeight: FontWeight.w600,
                            ),
                          ),
                          listener: controller.count,
                        ),
                      ),
                    ],
                  ),
                ],
              ),
            ],
          ),
        ),
      );
}

Extend MinController in your controller to get application lifecycles. Add your methods and your observables.

class MyController extends MinController {
  @override
  void onInit() {
    print('init controller');
    super.onInit();
  }

  final count = 0.minx;
  ValueNotifier<User> user = User().minx;

  increment() => count.value++;
  decrement() => count.value--;
  refresh() => count.value = 0;

  onChangedName(str) => user.update((val) => val.name = str);
  onSaveName(str) => user.update((val) => val.name = str);
  validateName(str) => str.length < 2 ? 'insert valid name' : null;
}
class User {
  User({this.name});
  String? name;
}

Additional information

Package is a work of studies about life cycles, dependency injection, objects and observable classes.
Not recommended and not ready for production.

Next steps:

• Fix navigation 2.0
• Provide controller for every page
• Add more complex usage examples
• Fix folders
• Fix imports