A widget that imposes additional constraints on its child.

For example, if you wanted child to have a minimum height of 50.0 logical pixels, you could use const BoxConstraints(minHeight: 50.0) as the constraints.

Sample code

This snippet makes the child widget (a Card with some Text) fill the parent, by applying BoxConstraints.expand constraints:

new ConstrainedBox(
  constraints: const BoxConstraints.expand(),
  child: const Card(child: const Text('Hello World!')),
)

The same behavior can be obtained using the new SizedBox.expand widget.

See also:

  • BoxConstraints, the class that describes constraints.
  • SizedBox, which lets you specify tight constraints by explicitly specifying the height or width.
  • FractionallySizedBox, a widget that sizes its child to a fraction of the total available space.
  • AspectRatio, a widget that attempts to fit within the parent's constraints while also sizing its child to match a given sapect ratio.
Inheritance

Constructors

ConstrainedBox({Key key, @required BoxConstraints constraints, Widget child })
Creates a widget that imposes additional constraints on its child. [...]

Properties

constraints BoxConstraints
The additional constraints to impose on the child.
final
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

Methods

createRenderObject(BuildContext context) RenderConstrainedBox
Creates an instance of the RenderObject class that this RenderObjectWidget represents, using the configuration described by this RenderObjectWidget. [...]
debugFillProperties(DiagnosticPropertiesBuilder description) → void
updateRenderObject(BuildContext context, RenderConstrainedBox 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.
inherited
debugDescribeChildren() List<DiagnosticsNode>
Returns a list of DiagnosticsNode objects describing this node's children. [...]
@protected, inherited
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. [...]
inherited
toDiagnosticsNode({String name, DiagnosticsTreeStyle style }) DiagnosticsNode
Returns a debug representation of the object that is used by debugging tools and by toStringDeep. [...]
inherited
toString({DiagnosticLevel minLevel: DiagnosticLevel.debug }) String
Returns a string representation of this object.
inherited
toStringDeep({String prefixLineOne: '', String prefixOtherLines, DiagnosticLevel minLevel: DiagnosticLevel.debug }) String
Returns a string representation of this node and its descendants. [...]
inherited
toStringShallow({String joiner: ', ', DiagnosticLevel minLevel: DiagnosticLevel.debug }) String
Returns a one-line detailed description of the object. [...]
inherited
toStringShort() String
A short, textual description of this widget.
inherited

Operators

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