How to retrieve address book contacts with Swift?

问题:

I don't understand why my code doesn't compile with Swift.

I am trying to convert this Objective-C code:

CFErrorRef error = NULL;
ABAddressBookRef addressBook = ABAddressBookCreateWithOptions(NULL, &error);

  if (addressBook != nil) { 
    NSLog(@"Succesful."); 

    NSArray *allContacts = (__bridge_transfer NSArray *)ABAddressBookCopyArrayOfAllPeople(addressBook);
}

This is my current rendition in Swift:

var error:CFErrorRef
var addressBook = ABAddressBookCreateWithOptions(nil, nil);

if (addressBook != nil) {
    println("Succesful.");

    var allContacts:CFArrayRef = ABAddressBookCopyArrayOfAllPeople(addressBook);
}

but, Xcode reports:

'Unmanaged' is not convertible to 'CFArrayRef'

Do you guys have an idea ?

回答1:

Obviously, if targeting iOS version 9 or greater, you shouldn't use the AddressBook framework at all, and instead use the Contacts framework instead.

So,

1. Import Contacts:

   import Contacts
   

2. Make sure to supply a NSContactsUsageDescription in your Info.plist.

3. Then, you can then access contacts. E.g. in Swift 3:

   let status = CNContactStore.authorizationStatus(for: .contacts)
   if status == .denied || status == .restricted {
       presentSettingsActionSheet()
       return
   }
   
   // open it
   
   let store = CNContactStore()
   store.requestAccess(for: .contacts) { granted, error in
       guard granted else {
           DispatchQueue.main.async {
               self.presentSettingsActionSheet()
           }
           return
       }
   
       // get the contacts
   
       var contacts = [CNContact]()
       let request = CNContactFetchRequest(keysToFetch: [CNContactIdentifierKey as NSString, CNContactFormatter.descriptorForRequiredKeys(for: .fullName)])
       do {
           try store.enumerateContacts(with: request) { contact, stop in
               contacts.append(contact)
           }
       } catch {
           print(error)
       }
   
       // do something with the contacts array (e.g. print the names)
   
       let formatter = CNContactFormatter()
       formatter.style = .fullName
       for contact in contacts {
           print(formatter.string(from: contact) ?? "???")
       }
   }
   

   Where

   func presentSettingsActionSheet() {
       let alert = UIAlertController(title: "Permission to Contacts", message: "This app needs access to contacts in order to ...", preferredStyle: .actionSheet)
       alert.addAction(UIAlertAction(title: "Go to Settings", style: .default) { _ in
           let url = URL(string: UIApplicationOpenSettingsURLString)!
           UIApplication.shared.open(url)
       })
       alert.addAction(UIAlertAction(title: "Cancel", style: .cancel))
       present(alert, animated: true)
   }
   

My original answer for AddressBook framework is below.

---

A couple of observations:

• If you want to use error parameter of ABAddressBookCreateWithOptions, define it to be Unmanaged<CFError>?.

• If it fails, take a look at the error object (doing takeRetainedValue so you don't leak).

• Make sure to takeRetainedValue of the address book, too, so you don't leak.

• You probably shouldn't just grab the contacts, but you probably should request permission first.

Pulling that all together you get:

// make sure user hadn't previously denied access

let status = ABAddressBookGetAuthorizationStatus()
if status == .Denied || status == .Restricted {
    // user previously denied, so tell them to fix that in settings
    return
}

// open it

var error: Unmanaged<CFError>?
guard let addressBook: ABAddressBook? = ABAddressBookCreateWithOptions(nil, &error)?.takeRetainedValue() else {
    print(error?.takeRetainedValue())
    return
}

// request permission to use it

ABAddressBookRequestAccessWithCompletion(addressBook) { granted, error in
    if !granted {
        // warn the user that because they just denied permission, this functionality won't work
        // also let them know that they have to fix this in settings
        return
    }

    if let people = ABAddressBookCopyArrayOfAllPeople(addressBook)?.takeRetainedValue() as? NSArray {
        // now do something with the array of people
    }
}