Programming iOS 10

Chapter 18. Contacts

The user’s contacts, which the user sees through the Contacts app, constitute a database that your code can access programmatically through the Contacts framework. You’ll need to import Contacts.

A user interface for interacting with the contacts database is provided by the Contacts UI framework. You’ll need to import ContactsUI.

Note

The Contacts framework, introduced in iOS 9, replaces the Address Book framework and the Address Book UI framework. The Address Book framework was an archaic C API without memory management information, so it was almost impossible to use in Swift, and it wasn’t all that usable in Objective-C either. The Address Book framework is not discussed in this edition.

Access to the contacts database requires user authorization. You’ll use the CNContactStore class for this. To learn what the current authorization status is, call the class method authorizationStatus(for:) with a CNEntityType of .contacts. To ask the system to put up the authorization request alert if the status is .notDetermined, call the instance method requestAccess(for:completionHandler:). The Info.plist must contain some text that the system authorization request alert can use to explain why your app wants access. The relevant key is “Privacy — Contacts Usage Description” (NSContactsUsageDescription). See “Music Library Authorization” for detailed consideration of authorization strategy and testing.

Contact Classes

Here are the chief object types you’ll be concerned ...