Flutter State Management

Introduction

State management refers to the process of managing the state of an application.

The state of an application is any piece of data that can change over time, such as the user's login status, the current screen being displayed, or the data being fetched from an API.

Managing the state of an application is essential because it helps ensure that the application remains responsive, performant, and bug-free.

In Flutter, state management is particularly crucial because of its reactive nature. Flutter is designed to be fast and responsive, which means that it needs to be able to quickly respond to changes in the application's state. As such, choosing the right state management technique is essential for building a successful Flutter application.

Importance of State Management in Flutter

• State management is crucial in Flutter for maintaining consistent app behavior.
• Proper state management ensures high-quality, performant, and reliable mobile applications.
• Poorly managed state can lead to performance issues and unexpected behavior such as slow rendering or memory leaks.
• Well-designed state management improves performance, reduces code complexity, and enhances scalability and maintainability.
• Effective and efficient state management becomes more crucial as Flutter applications grow in complexity and scale to the masses.

Types of State

Before we dive into the different state management techniques available in Flutter, it's important to understand the different types of states that exist in a Flutter application.

There are two main types of states in a Flutter application:

• Ephemeral state: This refers to the state that is only relevant to a single widget and doesn't need to be shared with other widgets in the tree. Ephemeral state is managed using the built-in setState method in Flutter.
• App state: This refers to the state that needs to be shared across multiple widgets in the widget tree. App state is managed using state management techniques such as InheritedWidget, Provider, Redux, and more.

State Management Techniques

1. Riverpod

Riverpod is a state management library for Flutter that is built on top of Provider. Riverpod is designed to make it easy for developers to manage the state of their application using a simple and intuitive API.

Some key features are:

• Offers powerful and automatic dependency injection capabilities to help manage state across different parts of an application
• Supports both local and global state management
• Offers granular control over when the state is rebuilt
• Provides a set of powerful debugging tools to help identify and troubleshoot state-related issues
• Highly customizable and flexible, allowing developers to create their own custom providers and extensions.

Pros:

• Simple and intuitive API
• Built-in support for lazy loading of providers.
• Enables efficient management of state across multiple widgets.
• Good documentation

Cons:

• Relatively new, so may have limited community support
• May not be suitable for very large applications with complex state management needs.
• Requires some understanding of the provider system and how it works.

2. setState

setState is a built-in method in Flutter that allows developers to update the state of a widget. This method is used to manage ephemeral states in a Flutter application.

Some key features of setState are:

• Easy to understand and use
• Provides instant updates to the UI when state changes
• Offers a straightforward and intuitive way to manage state for beginners.

Pros:

• Built-in to Flutter, so there is no need to install additional packages or libraries
• Can be used for managing ephemeral state efficiently

Cons:

• Limited to managing ephemeral state only
• Can be inefficient for managing large or complex states
• Can lead to spaghetti code if not used carefully.

3. InheritedWidget & InheritedModel

InheritedWidget is a built-in widget in Flutter that allows developers to share state across the widget tree. InheritedWidget can be used to manage app state in a Flutter application. On the other hand, InheritedModel is a variation of InheritedWidget that allows developers to selectively rebuild widgets that depend on specific parts of the app state.

Some of the key features are:

• Supports sharing state across multiple widgets within a widget tree
• Provides instant updates to the UI when state changes
• Suitable for managing simple, localized states across multiple widgets

Pros:

• Offers a straightforward and intuitive way to manage state for beginners.
• Built into Flutter, so no need to add any external dependencies
• Can be used for managing app state efficiently

Cons:

• Can be complex to set up and understand
• Can be inefficient for managing large or complex states

4. Redux

Redux is a popular state management library that originated in the React community and has since been ported to Flutter. Redux is designed to make it easy for developers to manage the state of their application using a single global store.

Some key features of Redux are:

• Provides a centralized, global store for managing application state
• Offers powerful middleware and middleware composition capabilities
• Supports time-travel debugging to help identify and troubleshoot state-related issues
• Supports a unidirectional data flow architecture.
• Supports hot-reloading for a faster development cycle.

Pros:

• Popular and well-established library with a large community
• Offers a clear separation of concerns between state management and UI components through the use of actions and reducers.

Cons:

• Can be complex to set up and understand
• Centralized state management can lead to bloated and complex codebases

5. Fish-Redux

Fish-Redux is a state management library that is inspired by the Model-View-Controller architecture. Fish-Redux is designed to make it easy for developers to manage the state of their application using a simple and intuitive API.

Some key features are:

• Offers a modular and component-based approach to state management
• Provides a centralized, global store for managing application state
• Offers powerful middleware and middleware composition capabilities
• Supports hot-reloading for a faster development cycle
• Provides a set of built-in widgets and adapters for managing state and rendering UI components.

Pros:

• Built-in support for asynchronous actions makes it easy to manage complex state changes
• Offers a flexible and scalable architecture for building applications.

Cons:

• Can be complex to set up and implement correctly.
• May be overkill for small applications with minimal state management requirements.
• Relatively new, so may have limited community support

6. BLoC / Rx

BLoC (Business Logic Component) is a state management library that is based on the ReactiveX (Rx) paradigm. BLoC is designed to make it easy for developers to manage the state of their application using a stream-based API.

Some features of BLoC are:

• Based on the reactive programming paradigm`, which allows for a more declarative approach to managing state
• Supports reactive programming and asynchronous data streams.
• Offers powerful tools for composing and transforming reactive streams, including operators like map, filter, and debounce
• Supports dependency injection to help manage state across different parts of an application
• Offers a consistent and intuitive API that is easy to learn and use.

Pros:

• Separation of business logic from UI makes it easy to manage complex state changes
• Stream-based API is powerful and flexible
• Built-in support for asynchronous events makes it easy to manage complex state changes

Cons:

• Can be complex to set up and implement correctly
• May require additional boilerplate code for implementing streams
• May not be the best fit for smaller or simpler applications

7. GetIt

GetIt is a state management library for Flutter that is built on top of the service locator pattern. It is not a technique for state management but a service to locate your objects. These service locators help us dissociate the main implementation and our interface, allowing access from everywhere.

Some of its features are:

• Supports both local and global state management
• Provides powerful dependency injection capabilities
• Offers a set of debugging tools to help identify and troubleshoot state-related issues
• Highly customizable

Pros:

• Offers a simple and intuitive API for managing state and dependencies
• Support for lazy initialization makes it easy to manage app state efficiently

Cons:

• May not be the best fit for larger or more complex applications
• Limited community support

8. MobX

MobX is a state management library that is based on the observer pattern. MobX is designed to make it easy for developers to manage the state of their applications using a simple and reactive programming model.

This is a unidirectional data flow model that allows developers to take care of the app state from outside the UI. This type of architecture is easy, as it helps you detect all changes reactively and then provide these changes to the UI.

Pros:

• Simple and intuitive programming model
• Automatic rebuilding of dependent widgets makes it easy to manage app state efficiently
• Support for the derived state is a powerful tool for managing complex state changes

Cons:

• Can be complex to set up
• May not be the best fit for smaller or simpler applications

9. Flutter Commands

Flutter Commands is a simple and lightweight state management solution for Flutter that uses ValueNotifiers to manage the state. It is designed to handle the state of a single widget or a small subtree of widgets.

Pros:

• Well-suited for small projects or simple applications
• No third-party dependencies are needed
• Low learning curve

Cons:

• Limited capabilities for handling complex state management scenarios
• Not suitable for large-scale applications
• Lack of community support and documentation

10. Binder

The binder is a state management library for Flutter that uses annotations to define the state and its dependencies. state management isolates the state of the app from the business logic. You can observe the entire app as many tiny states, all of which are independent of each other.

Pros:

• Reduces boilerplate code
• Increases code readability and maintainability
• Provides a clear separation between presentation and logic layers

Cons:

• Requires the use of annotations, which may not be preferred by some developers
• Limited community support and documentation

11. GetX

GetX is a lightweight and high-performance state management solution for Flutter. It offers a range of simple and elegant APIs for managing the state of the entire application.

Some of its features are:

• Dependency injection and state management are provided by a single library.
• Simplifies the syntax for reactive programming.
• Allows for easy implementation of reactive logic using state, worker, and stream workers.

Pros:

• Easy to learn and use
• Increases development speed as it comes with a variety of built-in utilities and widgets that can save time and effort during development.
• Provides a clean and concise syntax for routing in the application.

Cons:

• Requires the use of external dependencies
• Limited documentation and support for advanced features

12. states_rebuilder

states_rebuilder provides speedy creation and smooth state management through the usage of an integrated router and dependency injection solution. Boilerplate is reduced and the business logic is separated from the user interface.

Some of the key features of states_rebuilder include:

• Easy-to-use syntax for dependency injection and state management.
• Provides a clean and concise syntax for building reactive logic in the application.
• Supports hot reload and hot restart.

Pros:

• Easy to learn and use.
• Built-in mechanisms for handling errors, loading states, and refreshing data.
• Supports multiple stores for better organization and separation of concerns.
• Automatic rebuilding of dependent widgets makes it easy to manage app state efficiently
• Support for the derived state is a powerful tool for managing complex state changes

Cons:

• Can be complex to set up and understand
• Limited community support compared to other state management libraries

13. Triple Pattern (Segmented State Pattern)

The Triple Pattern, also known as the Segmented State Pattern, is a state management technique that is designed to make it easy for developers to manage the state of their application using a segmented programming model.

Triple is a pattern for state management that uses Streams or ValueNotifier. This mechanism (nicknamed triple because the stream always uses three values: Error, Loading, and State), is based on the Segmented State pattern.

Some of the key features of the Triple Pattern include:

• Segmented programming model
• Support for multiple state segments
• Built-in utilities and widgets reduce development time.

Pros:

• Supports separation of concerns for better organization and maintainability of the code.
• Allows for easy management of complex states and business logic.
• Automatic rebuilding of dependent widgets makes it easy to manage app state efficiently
• Support for multiple state segments allows for fine-grained control over app state

Cons:

• Limited community support compared to other state management libraries
• Can be complex to set up and understand

14. solidarity

solidarity is a state management library that is designed to make it easy for developers to manage the state of their application using a reactive programming model and is inspired by SolidJS.

Pros:

• Simple and intuitive programming model
• Automatic rebuilding of dependent widgets makes it easy to manage app state efficiently
• Support for the derived state is a powerful tool for managing complex state changes

Cons:

• Limited community support compared to other state management libraries
• Can be complex to set up and understand

15. flutter_reactive_widget

flutter_reactive_widget is an ultra-low-boilerplate solution for state management. It provides a way to handle streams of data and events in a reactive manner for state management in Flutter applications.

Some of its key features are:

• It is based on the ReactiveX framework, which handles asynchronous data streams.
• It also supports the separation of concerns for creating more modular and scalable applications.
• It includes several classes and utilities for managing state, including but not limited to ReactiveModel, ReactiveValue, and ReactiveList.

Pros:

• Actively maintained on GitHub with regular updates and contributions from the community.
• Widgets automatically update their display when the data they are bound to changes through listeners, allowing for a declarative UI that is easy to manage.
• Supports and includes a built-in dependency injection system, as well as support for popular dependency injection frameworks like get_it.

Cons:

• `Developers unfamiliar with reactive programming concepts may face a learning curve when adopting Flutter Reactive Widget.
• Unnecessary overhead and complexity in case of simple state management

Which State Management Technique is the right pick?

Choosing the right state management technique for your Flutter application can be a challenging task, as there are many different techniques to choose from, each with its own set of advantages and disadvantages as discussed above. However, there are several factors that you should consider when choosing a state management technique for your application, including but not limited to:

• Complexity of your application: The complexity of your application is one of the most important factors to consider when choosing a state management technique. If your application is small or relatively simple, you may not need a complex state management library. However, if your application is large or complex, you will likely need a more robust state management solution.
• Development team experience: The experience of your development team is another important factor to consider when choosing a state management technique. If your team has experience with a particular state management library, it may be easier and more efficient to use that library.
• Performance: Performance is always a consideration when developing mobile applications. Some state management libraries may hurt performance, so it's essential to choose a library that is optimized for performance.
• Community support: The community support for a state management library can also be an important factor to consider. Libraries with larger communities are likely to have more resources and support available, making it easier to troubleshoot issues and find answers to your questions.

Based on some of these factors and your specific project size and fit, you can choose the right state management technique for your application.

However, it's important to keep in mind that there is no one-size-fits-all solution. You may need to experiment with several different techniques before finding the one that works best for your application.

Best Practises for State Management in Flutter

While you have to make the choice of the right technique or approach for your application, it is equally crucial to also implement the techniques in the right way.

Here are some best practices to follow when using state management in Flutter:

• Keep your state small and focused: It's important to keep your app state as small and focused as possible. This will help to improve the performance of your application and make it easier to manage and maintain.
• Use immutable state: Immutable state can help to reduce the complexity of your application and make it easier to reason about. It also helps to prevent accidental state mutations, which can lead to unexpected behavior.
• Use a reactive programming model: Reactive programming models can help to make your code more efficient and easier to understand. They also make it easier to manage the state of your application.
• Use a state management library: Using a state management library can help to simplify your code and make it easier to manage your app state. There are many different libraries available, so choose the one that works best for your application.
• Test your app state: It's important to test your app state to ensure that it is working as expected. This can help to identify and prevent bugs and other issues.