ios备份和还原联系人无法正常工作

Question

我使用此代码恢复和备份iOS联系人。 Backup complete iPhone AdressBook programmatically 我在模拟器和设备中的联系人总是填充，但是 对于备用代码：

ABAddressBookRef addressBook = ABAddressBookCreate();
CFArrayRef peopleForBackup  = ABAddressBookCopyArrayOfAllPeople(addressBook);

CFDataRef vcards = (CFDataRef)ABPersonCreateVCardRepresentationWithPeople(peopleForBackup);

vcardString = [[NSString alloc] initWithData:(NSData *)vcards encoding:NSUTF8StringEncoding];

vcardString总是空字符串和  删除联系人＆＃39; arrayCount＆＃39;总是零：

ABAddressBookRef addressBook = ABAddressBookCreate();
CFArrayRef people = ABAddressBookCopyArrayOfAllPeople(addressBook);

int arrayCount = CFArrayGetCount(people);

ABRecordRef abrecord;

for (int i = 0; i < arrayCount; i++) {
    abrecord = CFArrayGetValueAtIndex(people, i);
}
}


CFRelease(people);

我也用过

 ABAddressBookCreateWithOptions(NULL, NULL);

用于创建＆＃39;地址簿＆＃39;对象但没有发生变化。 为什么会这样？ 任何人都可以帮助我吗？感谢＆＃39;