A Step-by-Step Guide for Bloc state management with Code Example
Flutter has become a highly sought-after choice for mobile app developers owing to its efficient framework and user-friendly interface. This open-source mobile application development framework facilitates the creation of visually appealing, high-performance apps for both Android and iOS platforms. The flexibility of Flutter's UI, its efficient widgets, and extensive support for multiple languages have contributed to its widespread acclaim.
To manage the state of an application, Flutter employs various state management techniques, including the Bloc state management approach. The Bloc state management library for Flutter is a simple yet powerful tool that aids developers in managing their application's state in a more organized manner.
Bloc state management approach in Flutter
The Flutter state management library known as Bloc follows the reactive programming paradigm and is highly effective in organizing an application's state. Bloc stands for Business Logic Component, indicating that it segregates the business logic from the application's UI layer. The Bloc approach promotes a clear distinction between the UI and business logic by assigning the responsibility of data presentation to the former and data processing to the latter. The tools provided by the Bloc state management library facilitate this separation, ensuring efficient handling of the application's state.
Implementing Bloc in a simple Flutter counter app
To understand how Bloc works in Flutter, let's take the example of a simple counter app.
This app will have a screen with a counter, and two buttons - one for incrementing the counter, and one for decrementing it.
To implement Bloc in this app, we need to create three files - 'main.dart', 'counter_bloc.dart', and 'counter_screen.dart'.
and to implement Bloc in our Flutter counter app, we need to import the 'flutter_bloc library'. This library provides the necessary classes and widgets for Bloc state management in Flutter. In our counter app, we import the following packages:
import 'package:flutter/material.dart';
import 'package:flutter_bloc/flutter_bloc.dart';The material.dart package provides the necessary widgets for building the UI of our app.
The flutter_bloc.dart package provides the necessary classes and widgets for Bloc state management in Flutter, such as the Cubit class and BlocProvider widget.
The 'main.dart' file is the entry point of our app, while the 'counter_bloc.dart' file contains the Bloc logic. The counter_screen.dart file contains the UI for our app.
The CounterBloc class in the counter_bloc.dart file extends the Cubit class from the Flutter Bloc library. The Cubit class is a reactive component that can emit state changes. We use the emit method to change the state of our counter. The CounterBloc class also contains two methods, increment and decrement, which increment and decrement the counter by 1.
The CounterScreen class in the counter_screen.dart file is a StatelessWidget that displays the UI of our app. We use the BlocProvider widget to provide the CounterBloc instance to our CounterScreen. The BlocBuilder widget then listens for changes to the state of the CounterBloc and rebuilds the UI accordingly.
The final step is to run our app using the main.dart file as the entry point. Our counter app is now fully functional, and we can increment and decrement the counter using the buttons on the screen.
A small sneak peek of the code in 'counter_bloc.dart' file, of the simple counter project.
import 'package:flutter_bloc/flutter_bloc.dart';
class CounterBloc extends Cubit<int> {
CounterBloc() : super(0);
void increment() => emit(state + 1);
void decrement() => emit(state - 1);
}
You can find the complete code on my github repository. click here
<screenshot of the app screen>
<screenshot of the app screen>
Flutter is a versatile and intuitive mobile application development framework that empowers developers with an array of powerful features and tools. Among these tools is the Bloc state management library, which helps developers manage their application's state more efficiently, thereby improving application performance. This article will guide you through the process of implementing Bloc in a simple counter app, highlighting its organizational capabilities for state management. By following these step-by-step instructions, you can easily implement Bloc in your Flutter apps, creating applications that are both efficient and responsive.
To further deepen your understanding of Flutter's capabilities, take a look at some of my other project examples, such as the to-do list app and BMI calculator, which demonstrate practical ways Flutter can be utilized for different types of applications.
If you're interested in learning more about Flutter and state management with Bloc, be sure to visit my LinkedIn profile for more informative content.
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anikethgupta
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