Programmatically Request Access to Contacts

As per this documentation on apple's site (scroll down to Privacy in the middle of the page), access to the address book must be granted before it can be access programmatically. Here is what I ended up doing.

  #import <AddressBookUI/AddressBookUI.h>

  // Request authorization to Address Book
  ABAddressBookRef addressBookRef = ABAddressBookCreateWithOptions(NULL, NULL);

  if (ABAddressBookGetAuthorizationStatus() == kABAuthorizationStatusNotDetermined) {
    ABAddressBookRequestAccessWithCompletion(addressBookRef, ^(bool granted, CFErrorRef error) {
      if (granted) {
          // First time access has been granted, add the contact
          [self _addContactToAddressBook];
      } else {
          // User denied access
          // Display an alert telling user the contact could not be added
      }
    });
  }
  else if (ABAddressBookGetAuthorizationStatus() == kABAuthorizationStatusAuthorized) {
    // The user has previously given access, add the contact
    [self _addContactToAddressBook];
  }
  else {
    // The user has previously denied access
    // Send an alert telling user to change privacy setting in settings app
  }

Update For iOS 9 and later:

From Apple website :

Important

The Address Book UI framework is deprecated in iOS 9. Use the APIs defined in the ContactsUI framework instead. To learn more, see ContactsUI

That did the perfect trick for me!

On iOS6, apple introduce new privacy control, user can control the accessment of contact and calender by each app. So, in the code side, you need to add some way to request the permission. In iOS5 or before, we can always call

ABAddressBookRef addressBook = ABAddressBookCreate();

to get the addressbook without any problem, but in iOS6, if you don't have permission, this call will just return empty pointer. That why we need to change the method to get ABAddressBookRef.

__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) {
    // Do whatever you want here.
}

In the code,semaphore is used for blocking until response, while ABAddressBookRequestAccessWithCompletion will ask for permission if the app didn't ask before. Otherwise it will just follow the settings in Settings-Privacy-Contact.

SOURCE: http://programmerjoe.blogspot.com/2012/10/ios6-permissions-contacts.html

For contacts framework:

- (void)checkPermissionForCNContacts
{
    switch ([CNContactStore authorizationStatusForEntityType:CNEntityTypeContacts])
    {
        case CNAuthorizationStatusNotDetermined:
        {
            [[[CNContactStore alloc] init] requestAccessForEntityType:CNEntityTypeContacts completionHandler:^(BOOL granted, NSError * _Nullable error) {
                if (granted == YES)
                    [self showCNContactPicker];
            }];
        }
            break;
        case CNAuthorizationStatusRestricted:
        case CNAuthorizationStatusDenied:
                // Show custom alert
            break;
        case CNAuthorizationStatusAuthorized:
            [self showCNContactPicker];
            break;
    }
}