Animations in Flutter are encapsulated as Animation objects that contain a typed value and a status (such as forward, reverse, completed, and dismissed). You can attach an animation object to a widget or listen for changes to the animation object. Based on changes to the animation object's properties, the framework can modify the way your widget appears and rebuild the widget tree.

Use the AnimationController class to specify how the animation should run. The AnimationController lets you define important characteristics of the animation, such as its duration and playback direction (forward or reverse).