States_Rebuilder: State Management for Flutter with a Focus on Declarative Programming and Functional Style

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States_Rebuilder: State Management for Flutter with a Focus on Declarative Programming and Functional Style

States_Rebuilder is a state management library for Flutter that emphasizes declarative programming, functional style, and simplicity. It provides a set of tools that enables developers to manage application state in a clear and concise manner. This article will introduce the key concepts of States_Rebuilder and guide you through its features with practical code examples.

Injecting State

One of the core features of States_Rebuilder is the ability to inject state into your widgets. Injected state is scoped to the widget that receives it, ensuring that it is only accessible within that widget's subtree. The following code demonstrates how to inject a simple integer state:

// In the global scope
final counter = 0.inj();

This injects a mutable ReactiveModel named 'counter' with an initial value of 0. ReactiveModels can be used to store any type of data and expose change notifications.

Listening to State Changes

States_Rebuilder provides several widgets that allow you to listen to state changes. OnReactive is a simple widget that wraps another widget and updates it whenever the injected state changes. Here's how you can use it:

OnReactive(
  () => Text('Counter value: $'),
);

This widget will display the current value of the 'counter' ReactiveModel.

Updating State

Updating the state of an injected ReactiveModel is straightforward. You can use the 'state' property to set or update the state. For example:

counter.state++;

This will increment the 'counter' ReactiveModel's value by 1.

ReactiveStatelessWidget

ReactiveStatelessWidget is a powerful widget that allows you to write reactive widgets without the need for StatefulWidget. It automatically tracks the state changes of the injected ReactiveModels and rebuilds the widget accordingly. Here's an example:

class CounterWidget extends ReactiveStatelessWidget {
  @override
  Widget build(BuildContext context) {
    return Text('Counter value: ${counter.state}');
  }
}

Dependency Injection

States_Rebuilder incorporates dependency injection to manage dependencies between widgets. The RM object provides a variety of methods to inject dependencies, such as RM.inject, RM.injectFuture, and RM.injectStream. This approach ensures that dependencies are properly resolved and avoids unnecessary rebuilds.

Lifecycle Management

Injected state has a lifecycle that is managed by the framework. It is created when first used and destroyed when no longer needed. This ensures that resources are properly released and prevents memory leaks.

Examples

States_Rebuilder provides several built-in features to handle common development tasks, including:

  • CRUD Operations: Create, Read, Update, and Delete operations with injected CRUD models.
  • Authentication and Authorization: User authentication and authorization using injected auth models.
  • App Theme Management: Dynamic app theme switching with injected theme models.
  • App Internationalization: App localization and internationalization using injected internationalization models.
  • Animation: Implicit and explicit animation with injected animation models.
  • Form Fields: Validation and submission of form fields using injected form models.
  • Scrolling List Views: Scroll tracking and end-of-list detection with injected scrolling models.
  • Page and Tab Views: Tab and page view management with injected tab page view models.

Conclusion

States_Rebuilder is a robust and developer-friendly state management library that empowers you to build reactive, maintainable, and testable Flutter applications. Its focus on declarative programming, functional style, and built-in features simplifies the development process and enhances code quality. Whether you are a beginner or an experienced Flutter developer, States_Rebuilder is worth exploring for its powerful capabilities and intuitive approach to state management.

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