ConstrainedLayoutBuilder<ConstraintType extends Constraints> class
Null safety
An abstract superclass for widgets that defer their building until layout.
Similar to the Builder widget except that the framework calls the builder function at layout time and provides the constraints that this widget should adhere to. This is useful when the parent constrains the child's size and layout, and doesn't depend on the child's intrinsic size.
The builder function is called in the following situations:
- The first time the widget is laid out.
- When the parent widget passes different layout constraints.
- When the parent widget updates this widget.
- When the dependencies that the builder function subscribes to change.
The builder function is not called during layout if the parent passes the same constraints repeatedly.
Subclasses must return a RenderObject that mixes in RenderConstrainedLayoutBuilder.
- Inheritance
-
- Object
- DiagnosticableTree
- Widget
- RenderObjectWidget
- ConstrainedLayoutBuilder
- Implementers
Constructors
- ConstrainedLayoutBuilder({Key? key, required Widget builder(BuildContext, ConstraintType)})
-
Creates a widget that defers its building until layout.
const
Properties
- builder → Widget Function(BuildContext, ConstraintType)
-
Called at layout time to construct the widget tree.
final
- hashCode → int
- The hash code for this object.
- key → Key?
-
Controls how one widget replaces another widget in the tree.
finalinherited
- runtimeType → Type
-
A representation of the runtime type of the object.
read-onlyinherited
Methods
-
createElement(
) → RenderObjectElement -
RenderObjectWidgets always inflate to a RenderObjectElement subclass.
override
-
createRenderObject(
BuildContext context) → RenderObject - Creates an instance of the RenderObject class that this RenderObjectWidget represents, using the configuration described by this RenderObjectWidget.
-
debugDescribeChildren(
) → List< DiagnosticsNode> -
Returns a list of
DiagnosticsNodeobjects describing this node's children.protected">@protectedinherited -
debugFillProperties(
DiagnosticPropertiesBuilder properties) → void -
Add additional properties associated with the node.
inherited
-
didUnmountRenderObject(
covariant 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">@protectedinherited
-
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 DiagnosticsNode.toStringDeep.
inherited
-
toString(
{DiagnosticLevel minLevel = DiagnosticLevel.info}) → String -
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
-
updateRenderObject(
BuildContext context, covariant RenderObject 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.
protected">@protectedinherited
Operators
-
operator ==(
Object other) → bool -
The equality operator.
nonVirtual">@nonVirtualinherited