Question

如果联系人的名字或姓氏为空白，则该值为nil还是""？

Answer 1

从Xcode 6 Beta 4开始，该值为nil。

要亲眼看看，请运行以下代码两次：

// AppDelegate.swift

import AddressBookUI
import UIKit

@UIApplicationMain
class AppDelegate: UIResponder, UIApplicationDelegate {
    var window: UIWindow!

    func application(application: UIApplication, didFinishLaunchingWithOptions launchOptions: NSDictionary?) -> Bool {
        var error: Unmanaged<CFError>?
        let addressBookTemp = ABAddressBookCreateWithOptions(nil, &error)
        if !addressBookTemp {
            println(error)
            return true
        }

        let addressBook = Unmanaged<NSObject>.fromOpaque(addressBookTemp.toOpaque()).takeRetainedValue()
        ABAddressBookRequestAccessWithCompletion(addressBook, nil)

        var allPeople: NSArray = ABAddressBookCopyArrayOfAllPeople(addressBook).takeRetainedValue()
        println("allPeople.count: \(allPeople.count)")

        for person in allPeople {
            let firstNameTemp = ABRecordCopyValue(person, kABPersonFirstNameProperty)
            let firstName: NSObject! = Unmanaged<NSObject>.fromOpaque(firstNameTemp.toOpaque()).takeRetainedValue()

            if firstName {
                println("firstName: \(firstName)")
            } else {
                println("fristName is nil")
            }

            let lastNameTemp = ABRecordCopyValue(person, kABPersonLastNameProperty)
            let lastName: NSObject! = Unmanaged<NSObject>.fromOpaque(lastNameTemp.toOpaque()).takeRetainedValue()

            if lastName {
                println("lastName: \(lastName)")
            } else {
                println("lastName is nil")
            }
        }
        return true
    }
}

Answer 2

如果某人没有姓或名，则该值为nil。如果要将其强制转换为空字符串，可以执行以下操作：

            // Getting the first and the last name of person
        let firstNameTemp = ABRecordCopyValue(person, kABPersonFirstNameProperty)?;
        let firstName: NSObject? = Unmanaged<NSObject>.fromOpaque(firstNameTemp!.toOpaque()).takeRetainedValue();
        var first_name = "";
        if firstName != nil {
            first_name = firstName! as NSString;
        }

        let lastNameTemp = ABRecordCopyValue(person, kABPersonLastNameProperty)?;
        let lastName: NSObject? = Unmanaged<NSObject>.fromOpaque(lastNameTemp!.toOpaque()).takeRetainedValue();
        var last_name = "";
        if lastName != nil {
            last_name = lastName! as NSString;
        }

iOS地址簿：个人记录的名字是否可以为零？

2 个答案: