attach method Null safety

  1. @mustCallSuper
void attach(
  1. covariant Object owner
)

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

@mustCallSuper
void attach(covariant Object owner) {
  assert(owner != null);
  assert(_owner == null);
  _owner = owner;
}