SizeObserver class
Widget which reports child size changes to onSizeChanged callback Useful if you want a parent widget to change behaviour depending on child size The size returned by the callback is computed depending on constraints
- Inheritance
Constructors
-
SizeObserver.new({Key? key, bool useDryLayout = true, PartialBoxConstraints? constraints, required ValueChanged<
Size> onSizeChanged, required Widget child}) -
const
Properties
- child → Widget?
-
The widget below this widget in the tree.
finalinherited
- constraints → PartialBoxConstraints?
-
Size measurements will be based on this constraints parameter
If null or if inner values are null, parent constraints will be used instead
final
- hashCode → int
-
The hash code for this object.
no setterinherited
- key → Key?
-
Controls how one widget replaces another widget in the tree.
finalinherited
-
onSizeChanged
→ ValueChanged<
Size> -
Callback for size change events
final
- runtimeType → Type
-
A representation of the runtime type of the object.
no setterinherited
- useDryLayout → bool
-
If true getDryLayout will be used instead of layout to compute child size
Using dry layout is more faster but some widget don't support it in that case consider using SafeDryLayout
final
Methods
-
createElement(
) → SingleChildRenderObjectElement -
RenderObjectWidgets always inflate to a RenderObjectElement subclass.
inherited
-
createRenderObject(
BuildContext context) → RenderObject -
Creates an instance of the RenderObject class that this
RenderObjectWidget represents, using the configuration described by this
RenderObjectWidget.
override
-
debugDescribeChildren(
) → List< DiagnosticsNode> -
Returns a list of DiagnosticsNode objects describing this node's
children.
inherited
-
debugFillProperties(
DiagnosticPropertiesBuilder properties) → void -
Add additional properties associated with the node.
override
-
didUnmountRenderObject(
covariant RenderObject renderObject) → void -
This method is called when a RenderObject that was previously
associated with this widget is removed from the render tree.
The provided RenderObject will be of the same type as the one created by
this widget's createRenderObject method.
inherited
-
noSuchMethod(
Invocation invocation) → dynamic -
Invoked when a nonexistent 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, int wrapWidth = 65}) → 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 RenderSizeObserver 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.
override
Operators
-
operator ==(
Object other) → bool -
The equality operator.
inherited