An Element that represents the runtime contract of a SetupWidget.
Elements are the instantiation of widgets in the element tree. Element subclasses implement setup to define their widget build behavior.
When a widget is inflated into an element tree, the framework calls the widget's
createElement method to create an element.
Provides access to lifecycleHooks, scope, and effect for managing the element's lifecycle and state.
This class should not be subclassed directly. Instead, extend SetupWidget to create a reusable widget component.
- Inheritance
-
- Object
- DiagnosticableTree
- Element
- SetupElement
Constructors
- SetupElement(SetupWidget widget)
-
Creates a new SetupElement with the given
widget.
Properties
- buildScope → BuildScope
-
A BuildScope whose dirty Elements can only be rebuilt by
BuildOwner.buildScope calls whose
contextargument is an Element within this BuildScope.no setterinherited - debugDoingBuild → bool
-
Whether the widget is currently updating the widget or render tree.
no setterinherited
- debugIsActive → bool
-
Returns true if the Element is active.
no setterinherited
- debugIsDefunct → bool
-
Returns true if the Element is defunct.
no setterinherited
- depth → int
-
An integer that is guaranteed to be greater than the parent's, if any.
The element at the root of the tree must have a depth greater than 0.
no setterinherited
- dirty → bool
-
Returns true if the element has been marked as needing rebuilding.
no setterinherited
-
effect
→ Effect<
void> -
The effect system for this element, which handles reactivity
and dependency tracking.
no setter
- hashCode → int
-
The hash code for this object.
no setterinherited
- lifecycleHooks → LifecycleHooks
-
Lifecycle hooks for managing the element's lifecycle events
like mount, unmount, update etc.
no setter
- mounted → bool
-
Whether the Widget this context is associated with is currently
mounted in the widget tree.
no setterinherited
- owner → BuildOwner?
-
The object that manages the lifecycle of this element.
no setterinherited
- renderObject → RenderObject?
-
The render object at (or below) this location in the tree.
no setterinherited
- renderObjectAttachingChild → Element?
-
Returns the child of this Element that will insert a RenderObject into
an ancestor of this Element to construct the render tree.
no setterinherited
- runtimeType → Type
-
A representation of the runtime type of the object.
no setterinherited
- scope → Scope
-
The scope associated with this element, used for dependency
tracking and cleanup.
no setter
- size → Size?
-
The size of the RenderBox returned by findRenderObject.
no setterinherited
- slot → Object?
-
Information set by parent to define where this child fits in its parent's
child list.
no setterinherited
- widget → SetupWidget
-
The configuration for this element.
no setteroverride
Methods
-
activate(
) → void -
Transition from the "inactive" to the "active" lifecycle state.
inherited
-
attachNotificationTree(
) → void -
Called in Element.mount and Element.activate to register this element in
the notification tree.
inherited
-
attachRenderObject(
Object? newSlot) → void -
Add renderObject to the render tree at the location specified by
newSlot.inherited -
deactivate(
) → void -
Transition from the "active" to the "inactive" lifecycle state.
inherited
-
deactivateChild(
Element child) → void -
Move the given element to the list of inactive elements and detach its
render object from the render tree.
inherited
-
debugDeactivated(
) → void -
Called, in debug mode, after children have been deactivated (see deactivate).
inherited
-
debugDescribeChildren(
) → List< DiagnosticsNode> -
Returns a list of DiagnosticsNode objects describing this node's
children.
inherited
-
debugExpectsRenderObjectForSlot(
Object? slot) → bool -
Whether the child in the provided
slot(or one of its descendants) must insert a RenderObject into its ancestor RenderObjectElement by calling RenderObjectElement.insertRenderObjectChild on it.inherited -
debugFillProperties(
DiagnosticPropertiesBuilder properties) → void -
Add additional properties associated with the node.
inherited
-
debugGetCreatorChain(
int limit) → String -
Returns a description of what caused this element to be created.
inherited
-
debugGetDiagnosticChain(
) → List< Element> -
Returns the parent chain from this element back to the root of the tree.
inherited
-
debugVisitOnstageChildren(
ElementVisitor visitor) → void -
Calls the argument for each child considered onstage.
inherited
-
dependOnInheritedElement(
InheritedElement ancestor, {Object? aspect}) → InheritedWidget -
Registers this build context with
ancestorsuch that whenancestor's widget changes this build context is rebuilt.inherited -
dependOnInheritedWidgetOfExactType<
T extends InheritedWidget> ({Object? aspect}) → T? -
Returns the nearest widget of the given type
Tand creates a dependency on it, or null if no appropriate widget is found.inherited -
describeElement(
String name, {DiagnosticsTreeStyle style = DiagnosticsTreeStyle.errorProperty}) → DiagnosticsNode -
Returns a description of the Element associated with the current build context.
inherited
-
describeMissingAncestor(
{required Type expectedAncestorType}) → List< DiagnosticsNode> -
Adds a description of a specific type of widget missing from the current
build context's ancestry tree.
inherited
-
describeOwnershipChain(
String name) → DiagnosticsNode -
Adds a description of the ownership chain from a specific Element
to the error report.
inherited
-
describeWidget(
String name, {DiagnosticsTreeStyle style = DiagnosticsTreeStyle.errorProperty}) → DiagnosticsNode -
Returns a description of the Widget associated with the current build context.
inherited
-
detachRenderObject(
) → void -
Remove renderObject from the render tree.
inherited
-
didChangeDependencies(
) → void -
Called when a dependency of this element changes.
inherited
-
dispatchNotification(
Notification notification) → void -
Start bubbling this notification at the given build context.
inherited
-
doesDependOnInheritedElement(
InheritedElement ancestor) → bool -
Returns
trueif dependOnInheritedElement was previously called withancestor.inherited -
findAncestorRenderObjectOfType<
T extends RenderObject> () → T? -
Returns the RenderObject object of the nearest ancestor RenderObjectWidget widget
that is an instance of the given type
T.inherited -
findAncestorStateOfType<
T extends State< (StatefulWidget> >) → T? -
Returns the State object of the nearest ancestor StatefulWidget widget
that is an instance of the given type
T.inherited -
findAncestorWidgetOfExactType<
T extends Widget> () → T? -
Returns the nearest ancestor widget of the given type
T, which must be the type of a concrete Widget subclass.inherited -
findRenderObject(
) → RenderObject? -
The current RenderObject for the widget. If the widget is a
RenderObjectWidget, this is the render object that the widget created
for itself. Otherwise, it is the render object of the first descendant
RenderObjectWidget.
inherited
-
findRootAncestorStateOfType<
T extends State< (StatefulWidget> >) → T? -
Returns the State object of the furthest ancestor StatefulWidget widget
that is an instance of the given type
T.inherited -
forgetChild(
Element child) → void -
Remove the given child from the element's child list, in preparation for
the child being reused elsewhere in the element tree.
inherited
-
getElementForInheritedWidgetOfExactType<
T extends InheritedWidget> () → InheritedElement? -
Obtains the element corresponding to the nearest widget of the given type
T, which must be the type of a concrete InheritedWidget subclass.inherited -
getInheritedWidgetOfExactType<
T extends InheritedWidget> () → T? -
Returns the nearest widget of the given InheritedWidget subclass
Tor null if an appropriate ancestor is not found.inherited -
inflateWidget(
Widget newWidget, Object? newSlot) → Element -
Create an element for the given widget and add it as a child of this
element in the given slot.
inherited
-
markNeedsBuild(
) → void -
Marks the element as dirty and adds it to the global list of widgets to
rebuild in the next frame.
inherited
-
mount(
Element? parent, Object? newSlot) → void -
Add this element to the tree in the given slot of the given parent.
inherited
-
noSuchMethod(
Invocation invocation) → dynamic -
Invoked when a nonexistent method or property is accessed.
inherited
-
performRebuild(
) → void -
Cause the widget to update itself.
inherited
-
reassemble(
) → void -
Called whenever the application is reassembled during debugging, for
example during hot reload.
inherited
-
rebuild(
{bool force = false}) → void -
Cause the widget to update itself. In debug builds, also verify various
invariants.
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 element.
inherited
-
unmount(
) → void -
Transition from the "inactive" to the "defunct" lifecycle state.
inherited
-
update(
covariant Widget newWidget) → void -
Change the widget used to configure this element.
inherited
-
updateChild(
Element? child, Widget? newWidget, Object? newSlot) → Element? -
Update the given child with the given new configuration.
inherited
-
updateChildren(
List< Element> oldChildren, List<Widget> newWidgets, {Set<Element> ? forgottenChildren, List<Object?> ? slots}) → List<Element> -
Updates the children of this element to use new widgets.
inherited
-
updateSlot(
Object? newSlot) → void -
Called by updateSlotForChild when the framework needs to change the slot
that this Element occupies in its ancestor.
inherited
-
updateSlotForChild(
Element child, Object? newSlot) → void -
Change the slot that the given child occupies in its parent.
inherited
-
visitAncestorElements(
ConditionalElementVisitor visitor) → void -
Walks the ancestor chain, starting with the parent of this build context's
widget, invoking the argument for each ancestor.
inherited
-
visitChildElements(
ElementVisitor visitor) → void -
Wrapper around visitChildren for BuildContext.
inherited
-
visitChildren(
ElementVisitor visitor) → void -
Calls the argument for each child. Must be overridden by subclasses that
support having children.
inherited
Operators
-
operator ==(
Object other) → bool -
Compare two widgets for equality.
inherited