[iOS] AddressBook

1. Address Book Programming Guide for iOS
1.1 Address Book Framework Reference for iOS
1.2 Address Book UI Framework Reference for iOS

2. Address Book Reference for iOS

3. Address Book UI Reference for iOS

4. AddressGroup sample code

5. ABAddressBook Reference
5.1 address book change notification callback

ABExternalChangeCallback
ABAddressBookRegisterExternalChangeCallback
ABAddressBookUnregisterExternalChangeCallback
example from Stack Overflow

6. ABPerson Reference
6.1. ABPerson Properties
6.2. An example to get all the properties.

7. ABGroup Reference

8. ABRecord Reference
9. Get All Keys