Flexible class

A widget that controls how a child of a Row, Column, or Flex flexes.

Using a Flexible widget gives a child of a Row, Column, or Flex the flexibility to expand to fill the available space in the main axis (e.g., horizontally for a Row or vertically for a Column), but, unlike Expanded, Flexible does not require the child to fill the available space.

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

See also:

Implemented by


Flexible({Key key, int flex: 1, FlexFit fit: FlexFit.loose, @required Widget child })
Creates a widget that controls how a child of a Row, Column, or Flex flexes.


fit FlexFit
How a flexible child is inscribed into the available space. [...]
flex int
The flex factor to use for this child [...]
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


applyParentData(RenderObject renderObject) → void
Write the data from this widget into the given render object's parent data. [...]
debugFillProperties(DiagnosticPropertiesBuilder description) → void
createElement() ParentDataElement<Flex>
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.
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({DiagnosticLevel minLevel: DiagnosticLevel.debug }) String
Returns 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 ==(other) bool
The equality operator. [...]