A Beginner’s Guide Flutter BLoC Patterns
Published: 2023-02-20 07:55:31

With the average person spending [3 to 4 hours](https://www.statista.com/statistics/1224510/time-spent-per-day-on-smartphone-us/#:~:text=According%20to%20a%20survey%20conducted,average%20on%20their%20phone%20daily) each day on their phones, mobile apps have become immensely popular in our daily lives. We use mobile apps to browse the internet, perform work tasks, organize our lives, and entertain ourselves. This is why companies worldwide have created [3.55 million](https://www.statista.com/statistics/276623/number-of-apps-available-in-leading-app-stores/#:~:text=During%20the%20third%20quarter%20of,million%20available%20apps%20for%20iOS.) mobile apps that are expected to generate more than [$935 billion](https://buildfire.com/app-statistics/#:~:text=Mobile%20apps%20are%20expected%20to,app%2050%2B%20times%20per%20day.) in revenue in 2023. 

With the importance of the mobile app industry, incredible advancements have been made in the tools and software used to create mobile apps. In recent years, Flutter has been a rising star in leading innovations in mobile app development for companies of all sizes and industries. 

A critical component that makes Flutter’s technology worthwhile is its Business Logic Components (BLoCs). By incorporating BLoCs, app developers can quickly create and revise complex mobile apps to improve functionality and the user experience. 

Understanding Flutter BLoC is crucial for mobile app developers to create the best applications possible. So let’s review the basics. 

#What is Flutter BLoC?

When starting to develop a Flutter application, one of the first concepts to understand is state management. There are various strategies for managing states, such as Riverpod, Provider, Inherited Widget, or even the simplest one, SetState(). 

However, when you look at job postings, you will notice that the most used state management tool in the Flutter framework is BLoC. Whether you are an experienced mobile developer or just beginning your Flutter journey, you will soon learn about BLoC state management and BLoC pattern Flutter.

#What is a BLoC?

BLoC stands for Business Logic Component, and it works by providing a Stream of events from the UI to BLoC. If something happens, it returns a new state back to the UI. This continuous flow of data makes it easy to manage.

BLoCs allow developers to separate an application’s business logic from its user interface. This makes the app’s code more unambiguous, scalable, and testable. Using BLoCs in Flutter app development, developers can create apps more quickly and revise them more easily. 

#4 Terms in Flutter Development#

In a BLoC pattern Flutter, there are four distinct layers that contain the necessary components of an app:

1. Presentation
Presentation refers to the widgets, states, and controllers of an app. 

2. Application
The application component refers to the services that run the mobile app. 

3. Domain
The domain includes the models needed to maintain app functionality. 

4. Data
The data component includes the repositories, data sources, and data transfer objects (DTOs).

#Why We Use BLoC Flutter#
BLoC has been a valuable component for many app developers, especially in Flutter app development. 

BLoC helps solve the code-sharing issues that are inherent in many mobile applications. This also improves data stream functionality to manage and propagate state changes during Flutter app development. 

BLoC helps app developers separate business logic from an app’s user interface. This allows UI components to only worry about UI coding and not the underlying logic. Through this system, teams and apps can run more efficiently, reducing operational costs and improving the user experience. 

#When to Use BLoC Flutter#
In order to understand when to use BLoC and when not to, we must be aware of the concept of Local State and Global State.

For example, if we take a login form, the validation of the form would be considered as Local State as it only applies to this part of the application. However, the API communication used to authenticate the user is regarded as a Global State since it affects the whole app.

#How to Implement BLoC Flutter#
When using Flutter BLoC, events are created to initiate interactions with the app, and then the BLoC responsible will produce the requested data with a state. 

Here’s how it would work in a real mobile app:

1. A user will click on a button to open a list of games. 
2. The event is initiated and informs the BLoC that the user wants a list of games. 
3. The BLoC requests the data, usually from a data repository.
4. Once the BLoC has the data, it will determine if the data is a Success or an Error. Once this is determined, the BLoC will emit a state or result. 
5. The view will listen to all the possible states that the BLoC could emit and reacts to them. For example, if BLoC emits a Success as a state, the view will rebuild it with a list of games. However, if the state is an Error, the view will rebuild with an error message. 

#Hire Flutter App Developers#
If you want to build an advanced, scalable, world-class app, then you should [hire flutter app developers](https://www.mitrais.com/a/flutter-app-development-company/). Flutter app development can lead to mobile apps that will help your company engage buyers, expand to new regions, and improve the user experience. 

Any business can improve its digital presence and functionality when they hire flutter app developers to deliver a state-of-the-art mobile app for its brand.