How do I correctly use ABAddressBookCreateWithOptions method in iOS 6?

Question

I am trying to understand the ABAdressBookCreateWithOptions and ABAddressBookRequestAccessWithCompletion methods in iOS 6.

The most information i have been able to find is the following, "To request access to contact data, call the ABAddressBookRequestAccessWithCompletion function after calling the ABAddressBookCreateWithOptions function."

I believe together these methods should alert the user to decide whether to allow the application access to contacts, however when I use them I am seeing no prompt.

Could someone provide some sample code of how these methods should be called together in a real world example? How do I create (CFDictionary) options? I have working code using the deprecated ABAddressBookCreate method, but need to update to iOS 6 to accommodate privacy concerns.

Thanks in advance to anyone who can shed some light here!

Answer 1

Now that the NDA has been lifted, here is my solution for this for the where you need replace a method which returns an Array. (If you'd rather not block while the user is deciding and are ready to potentially rewrite some of your existing code, please look at David's solution below):

ABAddressBookRef addressBook = ABAddressBookCreate();

__block BOOL accessGranted = NO;

if (ABAddressBookRequestAccessWithCompletion != NULL) { // we're on iOS 6
    dispatch_semaphore_t sema = dispatch_semaphore_create(0);

    ABAddressBookRequestAccessWithCompletion(addressBook, ^(bool granted, CFErrorRef error) {
        accessGranted = granted;
        dispatch_semaphore_signal(sema);
    });

    dispatch_semaphore_wait(sema, DISPATCH_TIME_FOREVER);
    dispatch_release(sema);    
}
else { // we're on iOS 5 or older
    accessGranted = YES;
}


if (accessGranted) {

    NSArray *thePeople = (__bridge_transfer NSArray*)ABAddressBookCopyArrayOfAllPeople(addressBook);
    // Do whatever you need with thePeople...

}

Hope this helps somebody...

Answer 2

Most answers I've seen to this question do crazy complicated things with GCD and end up blocking the main thread. It's not necessary!

Here's the solution I've been using (works on iOS 5 and iOS 6):

- (void)fetchContacts:(void (^)(NSArray *contacts))success failure:(void (^)(NSError *error))failure {
  if (ABAddressBookRequestAccessWithCompletion) {
    // on iOS 6

    CFErrorRef err;
    ABAddressBookRef addressBook = ABAddressBookCreateWithOptions(NULL, &err);

    if (err) {
      // handle error
      CFRelease(err);
      return;
    }

    ABAddressBookRequestAccessWithCompletion(addressBook, ^(bool granted, CFErrorRef error) {
      // ABAddressBook doesn't gaurantee execution of this block on main thread, but we want our callbacks to be
      dispatch_async(dispatch_get_main_queue(), ^{
        if (!granted) {
          failure((__bridge NSError *)error);
        } else {
          readAddressBookContacts(addressBook, success);
        }
        CFRelease(addressBook);
      });
    });
  } else {
    // on iOS < 6

    ABAddressBookRef addressBook = ABAddressBookCreate();
    readAddressBookContacts(addressBook, success);
    CFRelease(addressBook);
  }
}

static void readAddressBookContacts(ABAddressBookRef addressBook, void (^completion)(NSArray *contacts)) {
  // do stuff with addressBook
  NSArray *contacts = @[];

  completion(contacts);
}

Answer 3

The other high ranking answer has problems:

• it unconditionally calls API that don't exist in iOS older than 6, so your program will crash on old devices.
• it blocks the main thread, so your app is unresponsive, and not making progress, during the time the system alert s up.

Here's my MRC take on it:

        ABAddressBookRef ab = NULL;
        // ABAddressBookCreateWithOptions is iOS 6 and up.
        if (&ABAddressBookCreateWithOptions) {
          NSError *error = nil;
          ab = ABAddressBookCreateWithOptions(NULL, (CFErrorRef *)&error);
    #if DEBUG
          if (error) { NSLog(@"%@", error); }
    #endif
          if (error) { CFRelease((CFErrorRef *) error); error = nil; }
        }
        if (ab == NULL) {
          ab = ABAddressBookCreate();
        }
        if (ab) {
          // ABAddressBookRequestAccessWithCompletion is iOS 6 and up.
          if (&ABAddressBookRequestAccessWithCompletion) {
            ABAddressBookRequestAccessWithCompletion(ab,
               ^(bool granted, CFErrorRef error) {
                 if (granted) {
                   // constructInThread: will CFRelease ab.
                   [NSThread detachNewThreadSelector:@selector(constructInThread:)
                                            toTarget:self
                                          withObject:ab];
                 } else {
                   CFRelease(ab);
                   // Ignore the error
                 }
                 // CFErrorRef should be owned by caller, so don't Release it.
               });
          } else {
            // constructInThread: will CFRelease ab.
            [NSThread detachNewThreadSelector:@selector(constructInThread:)
                                     toTarget:self
                                   withObject:ab];
          }
        }
      }

Answer 4

This is peripherally related to the original question, but I have not seen it mentioned anywhere else, and it took me about two days to figure it out. If you register a callback for address book changes, it MUST be on the main thread.

For example, in this code, only sync_address_book_two() will ever be called:

ABAddressBookRequestAccessWithCompletion(_addressBook, ^(bool granted, CFErrorRef error) {
    if (granted) {
        ABAddressBookRegisterExternalChangeCallback (_addressBook, sync_address_book_one, NULL);
        dispatch_async(dispatch_get_main_queue(), ^{
            ABAddressBookRegisterExternalChangeCallback (_addressBook, sync_address_book_two, NULL);
        });
    }
});