13.10. Flutter Animations: Time Controlled Animations

Animations are an essential part of the user experience in modern applications. They add a touch of life and interactivity, making the user interface more intuitive and engaging. In Flutter, the animation library provides a powerful framework that makes it easy to create and manage interactive animations. In this chapter, we'll explore how to create timed animations in Flutter.

Understanding Animations in Flutter

Before we dive into timed animations, it's important to understand what animations are in Flutter. Animations are essentially a gradual change in a visual object over time. This could be anything from changing the color of a button to moving a widget from one side of the screen to the other.

Basic Concepts of Animation

In Flutter, animations are created using two main objects - Animation and AnimationController. An Animation object represents an animation itself and can have a value that changes over time. On the other hand, the AnimationController is what controls the animation. It determines the duration of the animation and provides methods to start, stop and control the direction of the animation.

Animations with Time Control

Timed animations are animations that can be controlled interactively by the user. For example, a user might want to pause an animation, jump to a specific point in the animation, or even reverse the animation. In Flutter, this is achieved using the AnimationController object.

Creating a Time Controlled Animation

To create a timed animation, we first need to create an AnimationController object. The AnimationController's constructor takes a duration that specifies how long the animation should last. We then use the AnimationController's animate method to create an Animation object that represents the animation itself. Here is an example:

final controller = AnimationController(
  duration: const Duration(seconds: 2),
);
final animation = controller.animate(
  Tween(begin: 0.0, end: 1.0),
);

In this example, we are creating an animation that lasts 2 seconds and animates from 0.0 to 1.0.

Controlling Animation

Once we have our animation, we can control it using the methods provided by AnimationController. For example, we can start the animation by calling the forward method:

controller.forward();

We can pause the animation by calling the stop method:

controller.stop();

We can also reverse the animation by calling the reverse method:

controller.reverse();

In addition, we can control the position of the animation using the value property of the AnimationController. For example, we can jump to halfway through the animation by setting the value to 0.5:

controller.value = 0.5;

In conclusion, timed animations in Flutter offer a powerful way to create interactive and engaging experiences for users. With the combination of Animation and AnimationController, we can create complex animations and control them interactively.