onCancelTap method
Pops the dialog from the navigation stack and returns the initially selected values.
Implementation
void onCancelTap(BuildContext ctx, List<T> initiallySelectedValues) {
  Navigator.pop(ctx, initiallySelectedValues);
}Pops the dialog from the navigation stack and returns the initially selected values.
void onCancelTap(BuildContext ctx, List<T> initiallySelectedValues) {
  Navigator.pop(ctx, initiallySelectedValues);
}