removeCallback method Null safety

  1. @override
void removeCallback(
  1. ValueGetter<Future<bool>> callback
)

Remove a previously registered callback.

If the given callback is not registered, the call is ignored.

Implementation

@override
void removeCallback(ValueGetter<Future<bool>> callback) {
  super.removeCallback(callback);
  if (!hasCallbacks) {
    WidgetsBinding.instance.removeObserver(this);
  }
}