我想以.vcf文件格式备份ios联系人

有人能解释一下如何在.vcf formate中进行联系人备份，iOS中的任何示例编码吗？

#导入
#import <AddressBook/AddressBook.h>

- (void)viewDidLoad {
    [super viewDidLoad];
    // Do any additional setup after loading the view, typically from a nib.

    ABAddressBookRef addressBook = ABAddressBookCreate();

    __block BOOL accessGranted = NO;

    if (ABAddressBookRequestAccessWithCompletion != NULL) { // We are on iOS 6
        dispatch_semaphore_t semaphore = dispatch_semaphore_create(0);

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

        dispatch_semaphore_wait(semaphore, DISPATCH_TIME_FOREVER);

    }

    else { // We are on iOS 5 or Older
        accessGranted = YES;
        [self getContactsWithAddressBook:addressBook];
    }

    if (accessGranted) {
        [self getContactsWithAddressBook:addressBook];
    }                
}

// Get the contacts.
- (void)getContactsWithAddressBook:(ABAddressBookRef )addressBook
{

    //----------------------------------------------- create vcf file------------------------------------------

    CFArrayRef contacts = ABAddressBookCopyArrayOfAllPeople(addressBook);
    CFDataRef vcards = (CFDataRef)ABPersonCreateVCardRepresentationWithPeople(contacts);
    NSString *vcardString = [[NSString alloc] initWithData:(__bridge NSData *)(vcards) encoding:NSUTF8StringEncoding];
    NSError *error;
    NSFileManager *fileMgr = [NSFileManager defaultManager];
    NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
    NSString *folderPath = [paths objectAtIndex:0];
    NSString *filePath = [folderPath stringByAppendingPathComponent:@"contacts.vcf"];
    NSLog(@"%@===>",filePath);
    [vcardString writeToFile:filePath atomically:YES encoding:NSUTF8StringEncoding error:nil];
    NSLog(@"Documents directory: %@",[fileMgr contentsOfDirectoryAtPath: folderPath error:&error]);

}

-（无效）viewDidLoad{
[超级视图下载]；
//加载视图后，通常从nib执行任何其他设置。
ABAddressBookRef addressBook=ABAddressBookCreate（）；
__block BOOL accessgrated=否；
如果（ABAddressBookRequestAccessWithCompletion！=NULL）{//我们在iOS 6上
dispatch\u semaphore\u t semaphore=dispatch\u semaphore\u create（0）；
ABAddressBookRequestAccessWithCompletion（addressBook，^（已授予bool，CFErrorRef错误）{
accessgrated=已授予；
调度信号灯（信号灯）；
});
调度信号灯等待（信号灯，调度时间永远）；
}
否则{//我们使用的是iOS 5或更高版本
accessgrated=是；
[self-getContactsWithAddressBook:addressBook]；
}
如果（已授予访问权限）{
[self-getContactsWithAddressBook:addressBook]；
}                
}
//获取联系人。
-（无效）getContactsWithAddressBook:（ABAddressBookRef）addressBook
{
//-----------------------------------------------创建vcf文件------------------------------------------
CFArrayRef contacts=abAddressBookCopyArrayFallPeople（地址簿）；
CFDataRef vcards=（CFDataRef）ABPersonCreateVCardRepresentationWithPeople（contacts）；
NSString*vcardString=[[NSString alloc]initWithData:（_桥NSData*）（vcards）编码：NSUTF8StringEncoding]；
n错误*错误；
NSFileManager*fileMgr=[NSFileManager defaultManager]；
NSArray*Path=NSSearchPathForDirectoriesInDomains（NSDocumentDirectory，NSUserDomainMask，是）；
NSString*folderPath=[paths objectAtIndex:0]；
NSString*filePath=[folderPath stringByAppendingPathComponent:@“contacts.vcf”]；
NSLog（@“%@===>”，文件路径）；
[vcardString writeToFile:filePath原子：是编码：NSUTF8StringEncoding错误：无]；
NSLog（@“Documents directory:%@，[fileMgr contentsOfDirectoryAtPath:folderPath错误：&error]）；
}

试试这个，它会有用的