A widget that expands a child of a Row, Column, or Flex.

Using an Expanded widget makes a child of a Row, Column, or Flex expand to fill the available space in the main axis (e.g., horizontally for a Row or vertically for a Column). If multiple children are expanded, the available space is divided amoung them according to the flex factor.

An Expanded widget must be a descendant of a Row, Column, or Flex, and the path from the Expanded widget to its enclosing Row, Column, or Flex must contain only StatelessWidgets or StatefulWidgets (not other kinds of widgets, like RenderObjectWidgets).

See also:

  • Flexible, which does not force the child to fill the available space.


Expanded({Key key, int flex: 1, @required Widget child })
Creates a widget that expands a child of a Row, Column, or Flex expand to fill the available space in the main axis.


child Widget
The widget below this widget in the tree.
final, inherited
fit FlexFit
How a flexible child is inscribed into the available space. [...]
final, inherited
flex int
The flex factor to use for this child [...]
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


applyParentData(RenderObject renderObject) → void
Write the data from this widget into the given render object's parent data. [...]
createElement() ParentDataElement<T>
Inflates this configuration to a concrete instance. [...]
debugCanApplyOutOfTurn() bool
Whether the ParentDataElement.applyWidgetOutOfTurn method is allowed with this widget. [...]
@protected, inherited
debugDescribeChildren() List<DiagnosticsNode>
Returns a list of DiagnosticsNode objects describing this node's children. [...]
@protected, inherited
debugDescribeInvalidAncestorChain({String description, String ownershipChain, bool foundValidAncestor, Iterable<Widget> badAncestors }) String
Subclasses should override this to describe the requirements for using the ParentDataWidget subclass. It is called when debugIsValidAncestor() returned false for an ancestor, or when there are extraneous ParentDataWidgets in the ancestor chain.
debugFillProperties(DiagnosticPropertiesBuilder description) → void
debugIsValidAncestor(RenderObjectWidget ancestor) bool
Subclasses should override this method to return true if the given ancestor is a RenderObjectWidget that wraps a RenderObject that can handle the kind of ParentData widget that the ParentDataWidget subclass handles. [...]
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 toStringDeep. [...]
toString() String
Returns a string representation of this object.
toStringDeep([String prefixLineOne = '', String prefixOtherLines ]) String
Returns a string representation of this node and its descendants. [...]
toStringShallow([String joiner = ', ' ]) String
Returns a one-line detailed description of the object. [...]
toStringShort() String
A short, textual description of this widget.


operator ==(other) bool
The equality operator. [...]