ImplicitlyAnimatedWidget class abstract

An abstract class for building widgets that animate changes to their properties.

Widgets of this type will not animate when they are first added to the widget tree. Rather, when they are rebuilt with different values, they will respond to those changes by animating the changes over a specified duration.

Which properties are animated is left up to the subclass. Subclasses' States must extend ImplicitlyAnimatedWidgetState and provide a way to visit the relevant fields to animate.

Relationship to AnimatedWidgets

ImplicitlyAnimatedWidgets (and their subclasses) automatically animate changes in their properties whenever they change. For this, they create and manage their own internal AnimationControllers to power the animation. While these widgets are simple to use and don't require you to manually manage the lifecycle of an AnimationController, they are also somewhat limited: Besides the target value for the animated property, developers can only choose a duration and curve for the animation. If you require more control over the animation (e.g. you want to stop it somewhere in the middle), consider using an AnimatedWidget or one of its subclasses. These widgets take an Animation as an argument to power the animation. This gives the developer full control over the animation at the cost of requiring you to manually manage the underlying AnimationController.

Common implicitly animated widgets

A number of implicitly animated widgets ship with the framework. They are usually named AnimatedFoo, where Foo is the name of the non-animated version of that widget. Commonly used implicitly animated widgets include:

• TweenAnimationBuilder, which animates any property expressed by a Tween to a specified target value.
• AnimatedAlign, which is an implicitly animated version of Align.
• AnimatedContainer, which is an implicitly animated version of Container.
• AnimatedDefaultTextStyle, which is an implicitly animated version of DefaultTextStyle.
• AnimatedScale, which is an implicitly animated version of Transform.scale.
• AnimatedRotation, which is an implicitly animated version of Transform.rotate.
• AnimatedSlide, which implicitly animates the position of a widget relative to its normal position.
• AnimatedOpacity, which is an implicitly animated version of Opacity.
• AnimatedPadding, which is an implicitly animated version of Padding.
• AnimatedPhysicalModel, which is an implicitly animated version of PhysicalModel.
• AnimatedPositioned, which is an implicitly animated version of Positioned.
• AnimatedPositionedDirectional, which is an implicitly animated version of PositionedDirectional.
• AnimatedTheme, which is an implicitly animated version of Theme.
• AnimatedCrossFade, which cross-fades between two given children and animates itself between their sizes.
• AnimatedSize, which automatically transitions its size over a given duration.
• AnimatedSwitcher, which fades from one widget to another.