removeListener method Null safety

  1. @override
void removeListener(
  1. VoidCallback listener
)
override

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

Implementation

@override
void removeListener(VoidCallback listener) {
  super.removeListener(listener);
  if (!hasListeners) {
    WidgetsBinding.instance.removeObserver(this);
  }
}