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Ravi Makhija
Ravi Makhija

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Best Practices to Implement the BLoC Architecture in Flutter

Flutter is a cross-platform framework backed by Google that allows app developers to create beautiful and feature-rich cross-stage applications which offer the ideal solution for your needs. It has multiple architectures:

  • BLoC
  • Vanilla
  • InheritedWidget
  • ChangeNotifier+Provider
  • Redux
  • MobX

Here We will discuss with you how to implement the BLoC architecture to create your mobile applications. BLoC (Business Logic Component) is an amazing architectural pattern that is built on separate components.

The BLoC components offer only business logic, which can be effortlessly shared between multiple Dart apps. Google introduced this architecture in 2019 at Google I/O and at present, it is believed to be one of the best performing Flutter architectures.

BLoC offers you a range of features that includes easy separation of the business logic from the presentation layer. This ensures that you can write code faster, reuse the codes and also easily test it.

As there are a large number of architectures of Flutter, you will find that no single one can satisfy every requirement. However, BLoC comes very close to offering an all-around solution without compromising on the robustness and efficiency of its structure.

The ability of BLoC that allows the app developers to create highly complex applications even with the help of modest parts makes it truly amazing.

Step-by-step Implementation of BLoC Architecture

The first step you need to create a Flutter app is to put together a design like MVVM, DDD, or Clean. After that, the architecture then arranges the various information streams in your app.

Once you have set up the architecture, the next step is to integrate the BLoC components into it.

Integrate the BLoC architecture into your project

The first step in implementing the BLoC architecture in the Flutter begins when you coordinate the BLoC library into your project. Furthermore, you have to include the Flutter bloc: ^2.0.1 reliance in your bar spec.YAML record.

Once this is done, you have the Flutter bundle that would allow you to put in place the BLoC design.

Install widgets in the BLoC library

There are multiple components in the BLoC library, which include the following:

  • BLoC
  • BLoCBuilder
  • BLoCProvider

These components are required to set up BLoCs and construct those BLoCs, which are needed by the progressions in the app’s state and set up conditions. This allows you to find out how to execute every gadget time and make use of it in your app’s business rationale.


The BLoC gadget is the primary segment that would allow you to perform various business rationale. To utilize it, you have to expand the BLoC class and replace the mapEventToState and initialState techniques. In the mapEventToState, you have to deal with various contentions that address the activities.

After you complete that, then you will have to return every contention as a state. Here is an example:


enum CounterEvent {increment, decrement} 
class CounterBloc extends Bloc { 
@override int get initialState => 0; 
@override Stream mapEventToState(CounterEvent event) async* { 
switch (event) { 
case CounterEvent.decrement: 
yield state – 1; break; case CounterEvent.increment: 
yield state + 1; break;}}}
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The example shows that you will find the CounterEvent and handle it by relying upon the occasion type. Once this is done, the express (int in this model) is then restored. If you have to edit the reaction, then you can make an occasion or a theoretical state.


//Customized state @immutable abstract class IncomingState {} 
class InitialIncomingState extends IncomingState {} 
class HandledState extends IncomingState { 
final int counter; 
HandledState(this.counter); }@immutable abstract class IncomingEvent {} 
class IncrementEvent extends IncomingEvent { 
IncrementEvent(); }class DecrementEvent extends IncomingEvent { 
DecrementEvent(); }
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The BLoCBuilder gadget reacts to any new states by creating BLoCs. It can be used on multiple occasions as it can react to changes in the state by creating gadgets that look like new UI components.

If you want to get a BLoC as a single gadget that will not be open using the BuildContext and BLoCProvider, then you have to indicate the BLoC like:


bloc: blocA, // provide the local bloc instance builder: (context, state) { 
// return widget here based on the state of BlocA})
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This important gadget is used as a reliance infusion. It can give the BLoCs a few gadgets at the same time that have a place along with the equivalent subtree. BLoCProvider is used to create blocks that can be accessed by all gadgets that are in the subtree.


builder: (BuildContext context) => BlocA(), child: ChildA(), );
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Make an event

To play out any activity with information - handle it, then send it through the web, now save it to the data set -you will need an occasion in your BLoC part. You must call this technique:


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That is all needed! Now the BLoC segment will interact with your occasion.


If you are planning to build a Flutter app, then you can settle on BLoC as it offers amazing code quality and also helps in managing the states in your app much more efficiently.

It is quite sophisticated as it uses technologies like Reactive Programming and Stream, which requires an experienced coder to get the best out of this architecture and create an amazing application for your business.

If you need any kind of help regarding the same then you can comment below or check out our flutter app development services for your projects regarding help. Our Flutter development company is an award-winning company and has built several apps for clients worldwide!

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