AnchorSubscription class abstract

A live handle on an Anchor's position/visibility, obtained via Anchor.subscribe. Listenable listeners are notified whenever the anchor may have moved, resized, or changed visibility. There's no explicit dispose method — implementations stop their internal work once the last listener is removed.

Implemented types

• Listenable

Constructors

AnchorSubscription()

Properties

anchorSize → Size?

The anchor's current box size, or null if not currently resolvable.

no setter

currentAnchorBox → RenderBox?

The anchor's currently-registered RenderBox, or null if it can't be resolved right now. Read at composite time by the popover's layout to measure the anchor's live on-screen position. Only meaningful when supportsCompositeTracking is true.

no setter

hashCode → int

The hash code for this object.

no setter, inherited

isVisible → bool

Whether the anchor currently resolves to a live, mounted render object.

no setter

runtimeType → Type

A representation of the runtime type of the object.

no setter, inherited

supportsCompositeTracking → bool

Whether this subscription supports tracking the anchor through the compositing pipeline (see currentAnchorBox).

no setter

Methods

addListener(VoidCallback listener) → void

Register a closure to be called when the object notifies its listeners.

inherited

computeTransform(RenderObject source) → Matrix4

Computes the transform that maps a point in the anchor's local coordinate space into source's local coordinate space.

noSuchMethod(Invocation invocation) → dynamic

Invoked when a nonexistent method or property is accessed.

inherited

removeListener(VoidCallback listener) → void

Remove a previously registered closure from the list of closures that the object notifies.

inherited

toString() → String

A string representation of this object.

inherited

Operators

operator ==(Object other) → bool

The equality operator.

inherited