AnimatedPositioned class

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

Only works if it's the child of a Stack.

This widget is a good choice if the size of the child would end up changing as a result of this animation. If the size is intended to remain the same, with only the position changing over time, then consider SlideTransition instead. SlideTransition only triggers a repaint each frame of the animation, whereas AnimatedPositioned will trigger a relayout as well.

Here's an illustration of what using this widget looks 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 position. If you require more control over the animation (e.g. if you want to stop it mid-animation), consider using a PositionedTransition instead, which takes a provided Animation as an 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 example transitions an AnimatedPositioned between two states. It adjusts the height, width, and Positioned properties when tapped.

To create a local project with this code sample, run:
flutter create --sample=widgets.AnimatedPositioned.1 mysample

See also:



AnimatedPositioned({Key? key, required Widget child, double? left, double? top, double? right, double? bottom, double? width, double? height, Curve curve = Curves.linear, required Duration duration, VoidCallback? onEnd})
Creates a widget that animates its position implicitly.
AnimatedPositioned.fromRect({Key? key, required Widget child, required Rect rect, Curve curve = Curves.linear, required Duration duration, VoidCallback? onEnd})
Creates a widget that animates the rectangle it occupies implicitly.


bottom double?
The offset of the child's bottom edge from the bottom of the stack.
child Widget
The widget below this widget in the tree.
curve Curve
The curve to apply when animating the parameters of this container.
duration Duration
The duration over which to animate the parameters of this container.
hashCode int
The hash code for this object.
no setterinherited
height double?
The child's height.
key Key?
Controls how one widget replaces another widget in the tree.
left double?
The offset of the child's left edge from the left of the stack.
onEnd VoidCallback?
Called every time an animation completes.
The offset of the child's right edge from the right of the stack.
runtimeType Type
A representation of the runtime type of the object.
no setterinherited
top double?
The offset of the child's top edge from the top of the stack.
width double?
The child's width.


createElement() StatefulElement
Creates a StatefulElement to manage this widget's location in the tree.
createState() AnimatedWidgetBaseState<AnimatedPositioned>
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.
debugFillProperties(DiagnosticPropertiesBuilder properties) → void
Add additional properties associated with the node.
noSuchMethod(Invocation invocation) → dynamic
Invoked when a nonexistent 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.