MenuAnchor class

A widget used to mark the "anchor" for a set of submenus, defining the rectangle used to position the menu, which can be done either with an explicit location, or with an alignment.

When creating a menu with MenuBar or a SubmenuButton, a MenuAnchor is not needed, since they provide their own internally.

The MenuAnchor is meant to be a slightly lower level interface than MenuBar, used in situations where a MenuBar isn't appropriate, or to construct widgets or screen regions that have submenus.

To programmatically control a MenuAnchor, like opening or closing it, or checking its state, you can get its associated MenuController. Use MenuController.maybeOf(BuildContext context) to retrieve the controller for the closest MenuAnchor ancestor of a given BuildContext. More detailed usage of MenuController is available in its class documentation.

This example shows how to use a MenuAnchor to wrap a button and open a cascading menu from the button. This example also shows how to use onAnimationStatusChanged to track animation status and toggle the menu.
link

To create a local project with this code sample, run:
flutter create --sample=material.MenuAnchor.1 mysample

This example shows how to use a MenuAnchor to create a cascading context menu in a region of the view, positioned where the user clicks the mouse with Ctrl pressed. The anchorTapClosesMenu attribute is set to true so that clicks on the MenuAnchor area will cause the menus to be closed.
link

To create a local project with this code sample, run:
flutter create --sample=material.MenuAnchor.2 mysample

This example demonstrates a simplified cascading menu using the MenuAnchor widget.
link

To create a local project with this code sample, run:
flutter create --sample=material.MenuAnchor.3 mysample

The MenuStyle.visualDensity setting only affects horizontal padding, and it will never make it negative. Vertical padding is not affected at all.

Inheritance

Constructors

Creates a const MenuAnchor.
const

Properties

alignmentOffset → Offset?
The offset of the menu relative to the alignment origin determined by MenuStyle.alignment on the style attribute and the ambient Directionality.
final
anchorTapClosesMenu → bool
Whether the menus will be closed if the anchor area is tapped.
final
animated → bool
Whether this widget should open or close a submenu with an animation.
final
builder → MenuAnchorChildBuilder?
The widget that this MenuAnchor surrounds.
final
child → Widget?
The optional child to be passed to the builder.
final
childFocusNode → FocusNode?
The childFocusNode attribute is the optional FocusNode also associated to the child or builder widget that opens the menu.
final
clipBehavior → Clip
The content will be clipped (or not) according to this option.
final
consumeOutsideTap → bool
Whether or not a tap event that closes the menu will be permitted to continue on to the gesture arena.
final
controller → MenuController?
An optional controller that allows opening and closing of the menu from other widgets.
final
crossAxisUnconstrained → bool
Determine if the menu panel can be wrapped by a UnconstrainedBox which allows the panel to render at its "natural" size.
final
hashCode → int
The hash code for this object.
no setterinherited
key → Key?
Controls how one widget replaces another widget in the tree.
finalinherited
An optional LayerLink to attach the menu to the widget that this MenuAnchor surrounds.
final
A list of children containing the menu items that are the contents of the menu surrounded by this MenuAnchor.
final
onAnimationStatusChanged → ValueChanged<AnimationStatus>?
An optional callback that is invoked when the AnimationStatus of the menu changes during open and close animations.
final
onClose → VoidCallback?
A callback that is invoked when the menu finishes closing.
final
onOpen → VoidCallback?
A callback that is invoked when the menu begins opening.
final
reservedPadding → EdgeInsetsGeometry?
The padding between the edge of the safe area and the menu panel.
final
runtimeType → Type
A representation of the runtime type of the object.
no setterinherited
style → MenuStyle?
The MenuStyle that defines the visual attributes of the menu bar.
final
useRootOverlay → bool
Whether the menu panel should be rendered in the root Overlay.
final

Methods

createElement() → StatefulElement
Creates a StatefulElement to manage this widget's location in the tree.
inherited
createState() → State<MenuAnchor>
Creates the mutable state for this widget at a given location in the tree.
override
debugDescribeChildren() → List<DiagnosticsNode>
Returns a list of DiagnosticsNode objects describing this node's children.
override
debugFillProperties(DiagnosticPropertiesBuilder properties) → void
Add additional properties associated with the node.
override
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

Operators

operator ==(Object other) → bool
The equality operator.
inherited