MeasuredSize class
Report size of widget tree.
In some applications knowing the size of a widget tree is required to determine layout strategies. This class, given a widget tree will report the size of that tree. The Offstage widget can be used to perform these calculations out of sight to the user.
The callback MeasureSizeCallback is called at the completion of the rendering cycle.
It should be noted that this requires an extra widget tree build if the subsequent builds are modified according to the MeasuredSize results.
An example of MeasuredSize usage is found in sample missile app
- Inheritance
- Object
- DiagnosticableTree
- Widget
- StatelessWidget
- Builder
- MeasuredSize
Constructors
- MeasuredSize({Key key, @required Widget child, @required MeasureSizeCallback callback, dynamic offstage: false})
- Constructs the MeasuredSize instance. [...]
Properties
- builder → WidgetBuilder
-
Called to obtain the child widget. [...]
final, inherited
- callback → MeasureSizeCallback
-
callback called at render completion
final
- child → Widget
-
widget tree to build
final
- hashCode → int
-
The hash code for this object. [...]
@nonVirtual, read-only, inherited
- key → Key
-
Controls how one widget replaces another widget in the tree. [...]
final, inherited
- offstage → dynamic
-
true if build is hidden
final
- runtimeType → Type
-
A representation of the runtime type of the object.
read-only, inherited
Methods
-
build(
BuildContext context) → Widget -
The build function used to intercept and measure the build cycle.
override
-
createElement(
) → StatelessElement -
Creates a StatelessElement to manage this widget's location in the tree. [...]
inherited
-
debugDescribeChildren(
) → List< DiagnosticsNode> -
Returns a list of DiagnosticsNode objects describing this node's
children. [...]
@protected, inherited
-
debugFillProperties(
DiagnosticPropertiesBuilder properties) → void -
Add additional properties associated with the node. [...]
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 DiagnosticsNode.toStringDeep. [...]
inherited
-
toString(
{DiagnosticLevel minLevel: DiagnosticLevel.info}) → 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 ==(
Object other) → bool -
The equality operator. [...]
@nonVirtual, inherited