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:

flutter pub add hook_state

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 StatelessWidget 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.

@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
useValueNotifier	Create a ValueNotifier and returns its value
useListenable	Listen a Listenable like ChangeNotifier
useListenableChanged	Listen a Listenable and execute a callback
useValueListenable	Listen a ValueNotifier 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'),
    );
  }
}

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.