iOS6.0下获取通讯录用户列表

自iOS6.0后获取通讯录列表需要询问用户，经过用户同意后才可以获取通讯录用户列表。而且ABAddressBookRef的初始化工作也由ABAddressBookCreate函数转变为ABAddressBookCreateWithOptions函数。下面代码是兼容之前版本的获取通讯录用户列表方法。

01 ABAddressBookRef addressBook = nil;
02
03 if ([[UIDevice currentDevice].systemVersion floatValue] >= 6.0)
04 {
05     addressBook = ABAddressBookCreateWithOptions(NULL, NULL);
06
07     //等待同意后向下执行
08     dispatch_semaphore_t sema = dispatch_semaphore_create(0);
09     ABAddressBookRequestAccessWithCompletion(addressBook, ^(bool granted, CFErrorRef error)
10     {
11         dispatch_semaphore_signal(sema);
12     });
13
14     dispatch_semaphore_wait(sema, DISPATCH_TIME_FOREVER);
15     dispatch_release(sema);
16 }
17 else
18 {
19     addressBook = ABAddressBookCreate();
20 }
21
22 NSArray *personArray = (NSArray *)ABAddressBookCopyArrayOfAllPeople(addressBook);