How to use method dataWithContacts in CNContactVCardSerialization?

Question

I am trying get NSData object with the vCard representation of the contact. My code:

let contactStore = CNContactStore()
let fetchRequest = CNContactFetchRequest(keysToFetch: [CNContactGivenNameKey, CNContactFamilyNameKey])

var contacts = [CNContact]()
var vcard = NSData()

    do{
            try contactStore.enumerateContactsWithFetchRequest(fetchRequest) { (contact, status) -> Void in
            self.fetchRequest.unifyResults = true
            self.contacts.append(contact)}

    } catch {
            print("Error \(error)")
      }


    do {
           try vcard = CNContactVCardSerialization.dataWithContacts(contacts)
    } catch {
          print("Error \(error)")
      } 

But, i get error:

Exception writing contacts to vCard (data): A property was not requested when contact was fetched. Error NilError.

I understand that the error in the access to contacts, but how to fix it?

Answer 1

I found the solution and it work:

let contactStore = CNContactStore()
var contacts = [CNContact]()
var vcardFromContacts = NSData()

let fetchRequest = CNContactFetchRequest(keysToFetch:[CNContactVCardSerialization.descriptorForRequiredKeys()])

do{
    try contactStore.enumerateContactsWithFetchRequest(fetchRequest, usingBlock: {
    contact, cursor in
    self.contacts.append(contact)})
} catch {
    print("Get contacts \(error)")
}

// Returns the vCard representation of the specified contacts

do {
    try vcardFromContacts = CNContactVCardSerialization.dataWithContacts(contacts)
} catch {
    print("vcardFromContacts \(error)")
}

But, whet i returns the contacts from the vCard data:

do {
    try contactsFromVcard = CNContactVCardSerialization.contactsWithData(vcardFromContacts)
} catch {
    print("contactsFromVcard \(error)")
}

field contact imageData has nil. Though it not nil.