13.2. Animations in Flutter: Basic animations

13.2. Flutter Animations: Basic Animations

Animations are an essential part of the user experience in mobile apps. They add life and personality to the interface, making it more interactive and engaging. In Flutter, animations are easy to implement thanks to its rich widget library and Dart programming language. In this section, we'll explore basic animations in Flutter and learn how to implement them in your application.

Introduction to Animations in Flutter

Animations in Flutter are built around the Animation object, which produces a numerical value that can be used to change the appearance of a widget over time. An Animation object can be used to generate a series of values ​​that represent a specific aspect of an animation, such as position, color, size, etc.

Animation in Flutter is typically created using two main components: an AnimationController and a Tween. The AnimationController controls the duration of the animation and provides a method to start the animation. Tween sets the start and end values ​​of the animation.

Implementing Basic Animations

To get started with basic animations in Flutter, we first need to create an AnimationController. This is an object that generates a sequence of numbers over time. The AnimationController requires a duration for the animation and a TickerProvider object, which generates tick events that drive the animation.

AnimationController controller = AnimationController(
  duration: const Duration(seconds: 2),
  vsync: this,
);

Next, we create a Tween. The Tween is an object that interpolates between two values ​​- in this case, between 0.0 and 1.0. Tween has an animate method that takes an AnimationController and produces an Animation.

Tween tween = Tween(begin: 0, end: 1);
Animation animation = tween.animate(controller);

Finally, we can start the animation by calling the forward method on the AnimationController.

controller.forward();

To use Animation in a widget, we can use the AnimatedBuilder widget. The AnimatedBuilder rebuilds itself whenever the Animation changes its value. In the builder method, we can use the Animation value to change the appearance of the widget.

AnimatedBuilder(
  animation: animation,
  builder: (BuildContext context, Widget child) {
    return Opacity(
      opacity: animation.value,
      child: child,
    );
  },
  child: FlutterLogo(size: 200),
);

Conclusion

Basic animations in Flutter are easy to implement and offer a powerful way to improve the user experience. With the combination of AnimationController and Tween, you can create complex, interactive animations that bring your applications to life. However, this is just the beginning. Flutter offers a variety of other classes and methods for creating more advanced animations, which we'll explore in future sections of this course.

Practice creating basic animations in Flutter and experiment with different values ​​and widgets to see how they affect how the animation looks and behaves. Remember, the best way to learn is by doing!