detach method
override
Mark this render object as detached from its PipelineOwner.
Typically called only from the parent's detach, and by the owner to mark the root of a tree as detached.
Subclasses with children should override this method to
detach all their children after calling the inherited method,
as in super.detach()
.
Implementation
@override
void detach() {
super.detach();
_horizontalOffset.removeListener(markNeedsLayout);
_verticalOffset.removeListener(markNeedsLayout);
_delegate.removeListener(_handleDelegateNotification);
for (final RenderBox child in _children.values) {
child.detach();
}
for (final RenderBox child in _keepAliveBucket.values) {
child.detach();
}
}