hook_state 0.2.1

A Flutter package inspired by React hooks and the `flutter_hooks` package. It offers a similar hooks experience but without the need for additional widgets, allowing you to use just `StatefulWidget` t [...]

Hook State

hook_state is a Flutter package inspired by React hooks and the flutter_hooks package. It offers a similar hooks experience but without the need for additional widgets, allowing you to use just StatefulWidget to manage complex states declaratively and reactively.

Motivation

The motivation behind this package is to provide a simpler and more intuitive development experience for managing state in Flutter. Unlike other packages that require the use of custom widgets, hook_state allows you to use just StatefulWidget, making the code cleaner and easier to maintain. This package is ideal to be used alongside widgets like ListenableBuilder and StreamBuilder.

Installation

Add the dependency to your pubspec.yaml:

dependencies:
  hook_state: ^1.0.0

Then, install the packages with the command:

flutter pub get

Usage

Basic Example

Here is a basic example of how to use hook_state to manage a counter.

First, create a new StatefulWidget. Then, use a HookStateMixin as a mixin in the State. After that, you can use the hook methods.

class _ExampleWidgetState extends State<ExampleWidget> with HookStateMixin {

You can also use the HookMixin directly in the Widget class, replacing the StatelessWidget.

class ExampleWidget extends Widget with HookMixin {

  Widget build(BuildContext context) {
    final counter = useNotifier<int>(0);
    return Text('$value');
  }
}

Now you can use a hooks methods in the `build` method.
This example uses the `useNotifier` hook to manage a `ValueNotifier` and return its value.

```dart
@override
  Widget build(BuildContext context) {
    final counter = useNotifier<int>(0);
    ...

See the full example below:

import 'package:flutter/material.dart';
import 'package:hook_state/hook_state.dart';

class ExampleWidget extends StatefulWidget {
  @override
  _ExampleWidgetState createState() => _ExampleWidgetState();
}

class _ExampleWidgetState extends State<ExampleWidget> with HookStateMixin {
  @override
  Widget build(BuildContext context) {
    final counter = useNotifier<int>(0);

    return Scaffold(
      appBar: AppBar(
        title: Text('Hook Example'),
      ),
      body: Center(
        child: Column(
          mainAxisAlignment: MainAxisAlignment.center,
          children: <Widget>[
            Text('You have pressed the button this many times:'),
            Text(
              '${counter.value}',
              style: Theme.of(context).textTheme.headline4,
            ),
          ],
        ),
      ),
      floatingActionButton: FloatingActionButton(
        onPressed: () {
          counter.value += 1;
        },
        tooltip: 'Increment',
        child: Icon(Icons.add),
      ),
    );
  }
}

Available Hooks

Hook	Description
useNotifier	Create a ValueNotifier and returns its value
useListenable	Listen a Listenable like ChangeNotifier
useListenableChanged	Listen a Listenable and execute a callback
useValueNotifier	Listen a ValueNotifier and returns its value
useValueSelector	Listen a ValueSelector and returns its value
useStream	Listens to a Stream and returns the latest emitted value
useStreamChanged	Listen a Listenable and execute a callback
useStreamController	Create a StreamController
useTextEditingController	Manages a TextEditingController
useFocusNode	Manages a FocusNode
useTabController	Manages a TabController
useScrollController	Manages a ScrollController
usePageController	Manages a PageController
useAnimationController	Manages an AnimationController

Creating Custom Hooks

You can create custom hooks by extending Hook and using extensions. Here’s an example:

Custom Hook for GlobalKey

Implementing the Custom Hook

import 'package:flutter/material.dart';
import 'package:hook_state/hook_state.dart';

extension CustomHookStateExtension on HookState {
  /// Registers a GlobalKeyHook to manage a GlobalKey.
  /// Returns the created GlobalKey.
  GlobalKey<T> useGlobalKey<T extends State<StatefulWidget>>() {
    final hook = GlobalKeyHook<T>();
    return use(hook).key;
  }
}

class GlobalKeyHook<T extends State<StatefulWidget>> extends Hook<GlobalKey<T>> {
  late final GlobalKey<T> key;

  GlobalKeyHook();

  @override
  void init() {
    key = GlobalKey<T>();
  }

  @override
  void dispose() {
    // GlobalKey does not need to be disposed.
  }
}

Using the Custom Hook

import 'package:flutter/material.dart';
import 'package:hook_state/hook_state.dart';

class ExampleCustomHookWidget extends StatefulWidget {
  @override
  _ExampleCustomHookWidgetState createState() => _ExampleCustomHookWidgetState();
}

class _ExampleCustomHookWidgetState extends State<ExampleCustomHookWidget> with HookStateMixin {
  @override
  Widget build(BuildContext context) {
    final key = useGlobalKey<_CustomWidgetState>();

    return Scaffold(
      appBar: AppBar(
        title: Text('Custom Hook Example'),
      ),
      body: Center(
        child: CustomWidget(key: key),
      ),
      floatingActionButton: FloatingActionButton(
        onPressed: () {
          key.currentState?.doSomething();
        },
        child: Icon(Icons.play_arrow),
      ),
    );
  }
}

class CustomWidget extends StatefulWidget {
  CustomWidget({Key? key}) : super(key: key);

  @override
  _CustomWidgetState createState() => _CustomWidgetState();
}

class _CustomWidgetState extends State<CustomWidget> {
  void doSomething() {
    print('Doing something!');
  }

  @override
  Widget build(BuildContext context) {
    return Container(
      child: Text('Custom Widget'),
    );
  }
}

Computed ValueNotifier with ValueSelector/AsyncValueSelector

ValueSelector

ValueSelector is a tool that allows you to derive new state from existing state in a Flutter application.

It is designed to compute a synchronous value based on a provided function. When the dependent state changes, ValueSelector will recompute the value and notify any listeners, so your UI can reactively update.

final nameState = ValueNotifier('name');
final lastNameState = ValueNotifier('last');

final fullNameSelector = ValueSelector<String>(
  (get) {
    final name = get(nameState);
    final lastName = get(lastNameState);
    return '$name $lastName';
  },
);

AsyncValueSelector

AsyncValueSelector is similar to ValueSelector but is designed for asynchronous operations. This means it can handle tasks like fetching data from an API or performing long-running calculations without blocking the main thread.

It ensures that only one asynchronous task is processed at a time, and notifies listeners once the new value is ready.

final userId = ValueNotifier<int>(1);

final userSelector = AsyncValueSelector<User>(
  (get) async {
    final id = get(userId);
    final response = await http.get('https://jsonplaceholder.typicode.com/users/$id');
    return User.fromJson(json.decode(response.body));
  },
);

Use the useValueSelector hooks to listen to the computed values.

Widget build(BuildContext context){
  final user = useValueSelector(userSelector);
  ...
}

## Contribution

Contributions are welcome! Feel free to open issues and pull requests on the GitHub repository.

## License

This project is licensed under the MIT License. See the LICENSE file for more information.

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This package was inspired by React hooks and the `flutter_hooks` package but aims to simplify the development experience in Flutter by eliminating the need for additional custom widgets.