What is the use of Mixins in Dart?

There are various object-oriented programming languages, and Dart is one of them that keeps the code clean and straightforward in development. It has abstract classes and interfaces, but there is one hidden feature known as Mixins. The concept of the mixins existed when you wished to inherit multiple classes at a similar time. In this blog, you see the use of Dart in developing the Flutter apps for your project.

What is Mixin?

Mixins are a way to modularize your codebase by allowing you to attach different code snippets to a single class or module. This can make your code easier to read and maintain, as you can keep related code together.

Here is a simple example of Mixin usage in Flutter:

	
mixin PrintMixin {
  void printData() {
    print("Printing data from Mixin");
  }
}


class ExampleClass with PrintMixin {
  void someMethod() {
    printData();
  }
}

In this example, the PrintMixin is a mixin that provides a printData method.
The ExampleClass uses the keyword to mix in the PrintMixin into its behavior. When someMethod is called on an instance of ExampleClass, it calls printData which is provided by the PrintMixin.

Why Mixin?

Mixins are used in Flutter for the following reasons:

1. Code Reusability:

Mixins allow to reuse of code in multiple classes without creating a subclass relationship.

2. Modular Design:

Mixins help to separate concerns and create modular and maintainable code.

3. Improved Readability:

Mixins allow to simplify the inheritance hierarchy and make the code easier to read and understand.

4. Multiple Inheritance:

Mixins allow inheritance from multiple classes, which is not possible in single inheritance systems.

5. Composition over Inheritance:

Mixins provide a way to compose objects from smaller parts, which is a more flexible and maintainable way of building complex objects.

Also Read: Flutter Rendering Widgets Using JSON Data

Pure Subclassing

In Flutter app development, pure subclassing refers to the traditional inheritance model, where a subclass inherits properties and behaviors from a superclass. It is a single inheritance model, meaning that a subclass can only inherit from one superclass.

Mixins, on the other hand, provide a way to inherit properties and behaviors from multiple classes in a composition-based manner, without creating a subclass relationship. With mixins, a class can inherit properties and behaviors from multiple mixins using with the keyword.

In pure subclassing, the subclass is tightly coupled with the superclass, and any changes to the superclass may affect the subclass. With mixins, the coupling is much looser, and changes to one mixin will not affect the others.

Therefore, pure subclassing is a simpler and more straightforward way of inheriting properties and behaviors, while mixins provide a more flexible and composable way of creating complex objects.

Mixins in Practice

Mixins are widely used in Flutter development to achieve code reuse and modular design. Here are some examples of how Mixins are used in practice:

1. State Management:

Mixins can be used to manage the state of Flutter widgets, for example, a StatefulMixin provides a way to manage the state of a widget.
>h3>2. Event Handling:

Mixins can be used to handle events, for example, a GestureMixin provides a way to handle gestures on a widget.

3. Animations:

Mixins can be used to manage animations, for example, an AnimationMixin provides a way to animate a widget.

4. Theming:

Mixins can be used to manage themes, for example, a ThemeMixin provides a way to apply a theme to a widget.

5. Logging:

Mixins can be used to log messages, for example, a LogMixin provides a way to log messages in a widget.

By using mixins, developers can build complex and reusable components by combining the properties and behaviors from multiple mixins. Mixins provide a way to build objects from smaller parts, which results in cleaner and more maintainable code.

Also Read: Use Regex In Dart

When to Use Mixins

The mixins we are going to look at are the tickerproviderstatemixin and the singletickerproviderstatemixin. Both of these mixins are used for explicit animations in Flutter. By specifying one of these mixins in our widget definition, we tell Flutter that the widget is animated and that we want to get notified for frame updates so that our animation controller can generate a new value and we can redraw the widget for the next animation step.

The SingletickerProviderStatemixin is used when you only have a single animation controller and the TickerProviderStatemixin is used when you have multiple animation controllers.

	
mixin SingleTickerProviderStateMixin<T extends StatefulWidget> on State<T>
   implements TickerProvider {
    Ticker? _ticker;
   @override
   Ticker createTicker(TickerCallback onTick) {
       // ...
       _ticker = Ticker(
           onTick,
           debugLabel:
               kDebugMode ? 'created by ${describeIdentity(this)}' : null
       );
       return _ticker!;
   }
   @override
   void didChangeDependencies() {
       if (_ticker != null)
           _ticker!.muted = !TickerMode.of(context);
       super.didChangeDependencies();
   }
   // ...
}

The code example is shortened to just get a quick overview. As you can see, the
SingleTickerProviderStateMixin makes use of the Flutter State-lifecycle methods. If we would now take a deeper look, we would also see that the Ticker that is used in the
SingleTickerProviderStateMixin inherits the StatelessWidget to trigger the redrawing.
One other area where mixins are heavily used in Dart and Flutter is JSON (de)serialization. Writing methods by hand to serialize and deserialize a data class is often error-prone and a repeating task. That’s one of the reasons why many developers resort to code generation Flutter app development tools to create that functionality. With mixins, the generated code can be easily included in the original data class.
There are many more examples where mixins are super useful, for example:

  • Service locators
  • i18n (Internationalization/Localization)
  • Logging
  • etc.

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Conclusion

Mixins are a powerful and flexible way to reuse code and achieve a modular design in Flutter development. They allow a class to inherit properties and behaviors from multiple classes without creating a subclass relationship, allowing the building of complex and reusable components from smaller parts. Mixins are widely used in Flutter for state management libraries, event handling, animations, theming, and logging, among other things.

When used appropriately, mixins can significantly improve the readability and maintainability of your code. Still, they should be used cautiously to ensure the code is clear and concise. Mixins are a crucial concept in Flutter development, and understanding when and how to use them is essential for creating compelling and maintainable Flutter applications.

However, you can hire Flutter developer if you face any issues while doing this in the development phase. Bosc Tech Labs has a development team, and you can consult them without hesitation. They will give you the desired outcomes to the clients and deliver them on time.

Frequently Asked Questions (FAQs)

1. What is the purpose of mixin?

Mixins are helpful when the programmer wants to share functionality between various classes. Besides repeating the same code repeatedly, a standard functionality is grouped into a mixin and included in each class that needs it.

2. How do you create the mixin in Flutter development?

To integrate the mixin, make the class that extends an Object and declares the no constructors. Unless you wish your mixin to be usable as the standard class, use the keyword mixin rather than the class.

3. What is the extension vs mixin Dart?

Mixin is how to reuse the class code in the various class hierarchies. Mixins also solve the problem and make the code reusable. In contrast, the extensions will add functionalities to existing classes without changing them for development.


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