Provider package in flutter : How to implement provider in flutter

What is state management in Flutter?

When developing the front-end app, it is necessary to handle the responses to each event triggered by UI activity. Technically, we must manage the state of UI components that change due to end-user interaction.

While managing the UI state, you may need to divide the massive UI into multiple smaller components while maintaining good communication.

Furthermore, all UI components should always know the application’s state.

Flutter supports various state management strategies, with the default setState function being the most basic. Although it is easy to use, you can only partially rely on it.

Other variables to consider when designing a Flutter app include app complexity, scalability, and architecture. That is why you want a comprehensive and successful strategy to state management.

Provider, BLoC, and Redux are Flutter’s most common state management options. 

Here we will talk about provider state management package.

The Provider package in Flutter is a widely-used state management solution that simplifies app development by ensuring efficient state sharing across widgets. In this article, we’ll dive into how to implement Provider in Flutter, explore its benefits, and showcase a complete guide to integrating it into your projects. If you’re looking to improve your Flutter app’s performance and readability, Provider is your go-to solution.

What is the Provider Package in Flutter?

The Provider package is an advanced yet simple dependency injection and state management library. Introduced as a recommended package by the Flutter team, it acts as a wrapper around InheritedWidget, making it easier to manage app states without boilerplate code. Whether you’re building small apps or complex enterprise-level projects, Flutter Provider makes managing states and dependencies seamless.

Why Use Provider in Flutter?

Here are some key reasons why developers choose Provider for Flutter state management:

1. Ease of Use: Simplifies the sharing of states and objects between widgets.
2. Performance Optimization: Prevents unnecessary widget rebuilds, ensuring efficient rendering.
3. Flexibility: Works well with various app sizes, from simple to complex architectures.
4. Flutter Community Recommendation: Backed by the Flutter team and trusted by developers globally.

How to Implement Provider in Flutter

Follow this step-by-step guide to implement the Provider package in Flutter:

Step 1: Add Provider Dependency

First, add the Provider package to your Flutter project. Open your pubspec.yaml file and include the dependency:

yamlCopy codedependencies:
  provider: ^6.0.5

Run the following command to fetch the dependency:

bashCopy codeflutter pub get

---

Step 2: Create a ChangeNotifier Class

ChangeNotifier is a class provided by the Flutter SDK that allows us to notify listeners when a state changes. Here’s an example of a basic counter state:

dartCopy codeimport 'package:flutter/foundation.dart';

class CounterProvider extends ChangeNotifier {
  int _count = 0;

  int get count => _count;

  void increment() {
    _count++;
    notifyListeners();
  }

  void decrement() {
    if (_count > 0) {
      _count--;
      notifyListeners();
    }
  }
}

---

Step 3: Wrap Your App with ChangeNotifierProvider

Wrap your app’s widget tree with a ChangeNotifierProvider to make the CounterProvider accessible throughout the app. Update your main.dart as follows:

dartCopy codeimport 'package:flutter/material.dart';
import 'package:provider/provider.dart';
import 'counter_provider.dart';

void main() {
  runApp(
    MultiProvider(
      providers: [
        ChangeNotifierProvider(create: (_) => CounterProvider()),
      ],
      child: const MyApp(),
    ),
  );
}

class MyApp extends StatelessWidget {
  const MyApp({Key? key}) : super(key: key);

  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      home: CounterScreen(),
    );
  }
}

---

Step 4: Use Provider in Your Widgets

You can now access the CounterProvider anywhere in your widget tree using Provider.of or Consumer. Here’s how you can create a counter UI:

dartCopy codeimport 'package:flutter/material.dart';
import 'package:provider/provider.dart';
import 'counter_provider.dart';

class CounterScreen extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(title: Text('Provider Example')),
      body: Center(
        child: Column(
          mainAxisAlignment: MainAxisAlignment.center,
          children: [
            Text(
              'Counter Value:',
              style: TextStyle(fontSize: 20),
            ),
            Consumer<CounterProvider>(
              builder: (context, counterProvider, _) {
                return Text(
                  '${counterProvider.count}',
                  style: TextStyle(fontSize: 40, fontWeight: FontWeight.bold),
                );
              },
            ),
            SizedBox(height: 20),
            Row(
              mainAxisAlignment: MainAxisAlignment.center,
              children: [
                ElevatedButton(
                  onPressed: () {
                    context.read<CounterProvider>().increment();
                  },
                  child: Text('Increment'),
                ),
                SizedBox(width: 20),
                ElevatedButton(
                  onPressed: () {
                    context.read<CounterProvider>().decrement();
                  },
                  child: Text('Decrement'),
                ),
              ],
            ),
          ],
        ),
      ),
    );
  }
}

---

Key Concepts in Provider for Flutter

1. ChangeNotifier: The backbone for state management, used to notify listeners about state changes.
2. ChangeNotifierProvider: Provides the ChangeNotifier instance to its descendants.
3. Consumer: Simplifies listening to state changes and rebuilding widgets.
4. context.read vs. context.watch:
   • context.read<T>(): Access the Provider instance without rebuilding the widget.
   • context.watch<T>(): Rebuild the widget when the Provider’s state changes.

---

Best Practices for Using Provider in Flutter

• Avoid Overusing Consumer: Minimize nesting by using context.read or Selector for optimized widget rebuilding.
• Separate Logic from UI: Keep your business logic in the ChangeNotifier classes for a clean architecture.
• Use MultiProvider: When dealing with multiple state providers, use MultiProvider to manage them efficiently.

Pros and Cons of Flutter Provider state management

Here are the key advantages and disadvantages of Flutter Provider state management.

Advantages of using Flutter Provider state management

• In Flutter, the Provider is a lightweight and adaptable state management option.
• In comparison to other solutions, it allows for a more granular and localized approach to state management.
• Provider supports dependency injection, making sharing object instances across your project simple.
• It works well with Flutter features like streams, ChangeNotifier, and ValueNotifier.

‍

Disadvantages of using Flutter Provider state management

• For beginners, the provider can be tough to set up and understand.
• It might not be the ideal choice for managing more sophisticated and dynamic states that must be shared by multiple widgets.