attach method Null safety
- covariant PipelineOwner owner
override
Mark this node as attached to the given owner.
Typically called only from the parent's attach method, and by the
owner to mark the root of a tree as attached.
Subclasses with children should override this method to first call their
inherited attach method, and then attach all their children to the
same owner.
Implementations of this method should start with a call to the inherited
method, as in super.attach(owner).
Implementation
@override
void attach(PipelineOwner owner) {
super.attach(owner);
_offset.addListener(markNeedsLayout);
}