AnimatedAlign class Null safety

Animated version of Align which automatically transitions the child's position over a given duration whenever the given alignment changes.

Here's an illustration of what this can look like, using a curve of Curves.fastOutSlowIn.

For the animation, you can choose a curve as well as a duration and the widget will automatically animate to the new target alignment. If you require more control over the animation (e.g. if you want to stop it mid-animation), consider using an AlignTransition instead, which takes a provided Animation as argument. While that allows you to fine-tune the animation, it also requires more development overhead as you have to manually manage the lifecycle of the underlying AnimationController.

The following code implements the AnimatedAlign widget, using a curve of Curves.fastOutSlowIn.
To create a local project with this code sample, run:
flutter create --sample=widgets.AnimatedAlign.1 mysample

See also:

  • AnimatedContainer, which can transition more values at once.
  • AnimatedPadding, which can animate the padding instead of the alignment.
  • AnimatedSlide, which can animate the translation of child by a given offset relative to its size.
  • AnimatedPositioned, which, as a child of a Stack, automatically transitions its child's position over a given duration whenever the given position changes.


AnimatedAlign({Key? key, required AlignmentGeometry alignment, Widget? child, double? heightFactor, double? widthFactor, Curve curve = Curves.linear, required Duration duration, VoidCallback? onEnd})
Creates a widget that positions its child by an alignment that animates implicitly.


alignment AlignmentGeometry
How to align the child.
child Widget?
The widget below this widget in the tree.
curve Curve
The curve to apply when animating the parameters of this container.
final, inherited
duration Duration
The duration over which to animate the parameters of this container.
final, inherited
hashCode int
The hash code for this object.
@nonVirtual, read-only, inherited
heightFactor double?
If non-null, sets its height to the child's height multiplied by this factor.
key Key?
Controls how one widget replaces another widget in the tree.
final, inherited
onEnd VoidCallback?
Called every time an animation completes.
final, inherited
runtimeType Type
A representation of the runtime type of the object.
read-only, inherited
widthFactor double?
If non-null, sets its width to the child's width multiplied by this factor.


createElement() StatefulElement
Creates a StatefulElement to manage this widget's location in the tree.
createState() AnimatedWidgetBaseState<AnimatedAlign>
Creates the mutable state for this widget at a given location in the tree.
debugDescribeChildren() List<DiagnosticsNode>
Returns a list of DiagnosticsNode objects describing this node's children.
@protected, inherited
debugFillProperties(DiagnosticPropertiesBuilder properties) → void
Add additional properties associated with the node.
noSuchMethod(Invocation invocation) → dynamic
Invoked when a non-existent method or property is accessed.
toDiagnosticsNode({String? name, DiagnosticsTreeStyle? style}) DiagnosticsNode
Returns a debug representation of the object that is used by debugging tools and by DiagnosticsNode.toStringDeep.
toString({DiagnosticLevel minLevel =}) String
A string representation of this object.
toStringDeep({String prefixLineOne = '', String? prefixOtherLines, DiagnosticLevel minLevel = DiagnosticLevel.debug}) String
Returns a string representation of this node and its descendants.
toStringShallow({String joiner = ', ', DiagnosticLevel minLevel = DiagnosticLevel.debug}) String
Returns a one-line detailed description of the object.
toStringShort() String
A short, textual description of this widget.


operator ==(Object other) bool
The equality operator.
@nonVirtual, inherited