22. State Management in Flutter (Provider, Bloc, Mobx)
State management is a critical aspect of building Flutter applications. Flutter offers various approaches to handle state, including Provider, Bloc (Business Logic Component), and MobX. In this tutorial, we'll explore each of these state management techniques with examples.
1.Provider
Provider is a straightforward state management solution that comes with the Flutter ecosystem. It helps manage state efficiently, especially for widget trees.
Step 1: Add the 'provider' Package
In your 'pubspec.yaml' file, add the 'provider' package as a dependency:
Run 'flutter pub get' to fetch the package. Make sure to replace '^latest_version' with the latest version available on pub.dev.
Step 2: Create a Model Class
Define a model class to represent your application's data. For example, let's create a simple 'Counter' model:
class Counter {
int value = 0;
void increment() {
value++;
}
}
Step 3: Implement Provider
Wrap your app with a 'ChangeNotifierProvider' or 'provider' widget at the top level of your widget tree. In this example, we'll use 'ChangeNotifierProvider':
Run 'flutter pub get' to fetch the packages. Replace '^latest_version' with the latest version available on pub.dev and pub.dev.
Step 2: Create a MobX Store
Define a MobX store class to handle your application's state. Let's create a simple 'CounterStore':
import 'package:mobx/mobx.dart';
part 'counter_store.g.dart';
class CounterStore = _CounterStore with _$CounterStore;
abstract class _CounterStore with Store {
@observable
int value = 0;
@action
void increment() {
value++;
}
}
Step 3: Generate MobX Code
Run the following command to generate MobX-related code:
flutter packages pub run build_runner build
This generates the necessary files, including 'Counter_store.g.dart'.
Step 4: Implement MobX
Initialize and use the 'CounterStore' in your widget tree:
This example creates a simple counter app using the MobX state management library.
Conclusion:
State management is crucial for building Flutter applications, and each approach has its use cases. Provider is excellent for small to medium-sized apps, Bloc is suitable for complex apps with a lot of business logic, and MobX offers a reactive approach to state management. Choose the one that best fits your project's needs and complexity.