A widget that aligns its child within itself and optionally sizes itself based on the child's size.

For example, to align a box at the bottom right, you would pass this box a tight constraint that is bigger than the child's natural size, with an alignment of FractionalOffset.bottomRight.

This widget will be as big as possible if its dimensions are constrained and widthFactor and heightFactor are null. If a dimension is unconstrained and the corresponding size factor is null then the widget will match its child's size in that dimension. If a size factor is non-null then the corresponding dimension of this widget will be the product of the child's dimension and the size factor. For example if widthFactor is 2.0 then the width of this widget will always be twice its child's width.

See also:

Implemented by


Align({Key key, FractionalOffset alignment: FractionalOffset.center, double widthFactor, double heightFactor, Widget child })

Creates an alignment widget.



alignment FractionalOffset

How to align the child.

heightFactor double

If non-null, sets its height to the child's height multipled by this factor.

widthFactor double

If non-null, sets its width to the child's width multipled by this factor.

child Widget

The widget below this widget in the tree.

final, inherited
hashCode int

The hash code for this object.

read-only, inherited
key Key

Controls how one widget replaces another widget in the tree.

final, inherited
runtimeType Type

A representation of the runtime type of the object.

read-only, inherited


createRenderObject(BuildContext context) RenderPositionedBox

Creates an instance of the RenderObject class that this RenderObjectWidget represents, using the configuration described by this RenderObjectWidget.

debugFillDescription(List<String> description) → void

Add additional information to the given description for use by toString.

updateRenderObject(BuildContext context, RenderPositionedBox renderObject) → void

Copies the configuration described by this RenderObjectWidget to the given RenderObject, which will be of the same type as returned by this object's createRenderObject.

createElement() SingleChildRenderObjectElement

RenderObjectWidgets always inflate to a RenderObjectElement subclass.

didUnmountRenderObject(RenderObject, renderObject) → void

A render object previously associated with this widget has been removed from the tree. The given RenderObject will be of the same type as returned by this object's createRenderObject.

@protected, inherited
noSuchMethod(Invocation invocation) → dynamic

Invoked when a non-existent method or property is accessed.

toString() String

Returns a string representation of this object.

toStringShort() String

A short, textual description of this widget.



operator ==(other) bool

The equality operator.