CNUI ERROR Selection predicates are set but the delegate does not implement contactPicker:didSelectContact: - objective-c

Question

I try to use the new iOS 9.0 CNContactPickerViewController to select a contact in objective-C. I set the delegate and implement the CNContactPickerDelegate methods.
#import ContactsUI;
#import Contacts;
//-----------------------------------------------------------------------
- (void) presentContacts
{
CNContactPickerViewController *contactPicker = [[CNContactPickerViewController alloc] init];
contactPicker.delegate = self;
contactPicker.predicateForEnablingContact = [NSPredicate predicateWithFormat:#"familyName LIKE[cd] 'smith'"];
contactPicker.predicateForSelectionOfContact = [NSPredicate predicateWithFormat:#"TRUEPREDICATE"];
[_myViewController presentViewController:contactPicker animated:YES completion:nil];
}
//-----------------------------------------------------------------------
- (void) contactPickerDidCancel: (CNContactPickerViewController *) picker
{
NSLog(#"didCancel");
}
//-----------------------------------------------------------------------
- (void) contactPicker: (CNContactPickerViewController *) picker
didSelectContact: (CNContact *) contact
{
NSLog(#"didSelectContact"):
}
//-----------------------------------------------------------------------
- (void) contactPicker: (CNContactPickerViewController *) picker
didSelectContactProperty: (CNContactProperty *) contactProperty
{
NSLog(#"didSelectProperty");
}
//-----------------------------------------------------------------------
The contacts picker is presented with 'smith' selectable but I get the following message:
[CNUI ERROR] Selection predicates are set but the delegate does not implement contactPicker:didSelectContact: and contactPicker:didSelectContactProperty:. Those predicates will be ignored.
And I never get any log from the delegate methods. It behaves exactly as the line
contactPicker.delegate = self;
is ignored. Even I click on the "cancel" button in the picker, I don't get my "didCancel" message but I get another message:
plugin com.apple.MobileAddressBook.ContactsViewService invalidated
I found in https://forums.developer.apple.com/thread/12275 somebody with the similar problem in swift and he solved it telling us: "So I found that the ContactsPicker I was calling was in the wrong module" but I do not understand how we can get the wrong module and how to call the "right" module.
I have the same problem on the simulator and on a real device (iPad).

Answer 1

Thanks to Joel in my related question With CNContactPickerViewController in iOS 9.0, how to enable/disable single or multiple selection?, I found that I just forgot to store the CNContactPickerViewController in a property that exists the time the user make the selection.
So my code becomes:
- (void) presentContacts
{
_contactPicker = [[CNContactPickerViewController alloc] init];
contactPicker.delegate = self;
...
}