hierarchyListener
Runs onHierarchyChange when the component's place in the hierarchy changes - it is handed to a parent, loses one, or starts or stops being on screen. The event's change flags say which.
onHierarchyChange is read when the event fires, so writing a fresh lambda on every recomposition registers nothing again.
Return
this chain with the hierarchy callback declared on it.
Parameters
receives the event; its changeFlags hold the HierarchyEvent.*_CHANGED bits, and changed is the component the change happened to - this component itself or one of its ancestors.
See also
Attaches a HierarchyListener (addHierarchyListener/removeHierarchyListener).
Return
this chain with the hierarchy listener declared on it.
Parameters
attached by identity, so a remembered instance stays put while a fresh one on every pass is detached and re-added.