如何使用核心數據將此代碼更改為swift 2？

Question

我正在嘗試遵循這個示例，但是我意識到它並不迅速。我是Swift的新手，所以我不知道如何將其更改為其他內容。 有人可以幫忙嗎？

import UIKit
import CoreData

class ViewController: UIViewController {

    @IBOutlet weak var firstName: UITextField!
    @IBOutlet weak var lastName: UITextField!
    @IBOutlet weak var timeLabel: UITextField!
    @IBOutlet weak var costLabel: UITextField!
    @IBOutlet weak var commentLabel: UITextField!

    let maContext = (UIApplication.sharedApplication().delegate as AppDelegate).managedObjectContext

    override func viewDidLoad() {
        super.viewDidLoad()
    }

    override func didReceiveMemoryWarning() {
        super.didReceiveMemoryWarning()
    }

    @IBAction func saveClient(sender: AnyObject) {
        let personDescription = NSEntityDescription.entityForName("Person", inManagedObjectContext: maContext)
    }

    // let person = Person(entity: personDescription!, insertIntoManagedObjectContext: maContext)

    person.fName = firstName.text
    person.lName = lastName.text
    person.time = timeLabel.int
    person.cost = costLabel.int
    person.comments = commentLabel.text

    var error:NSError?

    maContext?.save(&error)

    if let err = error
    {
        let a  = UIAlertView(title: "Error", message: err.localizedFailureReason, delegate: nil, cancelButtonTitle: "OK")
        a.show()
    }
    else{
        let a = UIAlertView(title: "Success", message: "Your Record is saved" , delegate: nil, cancelButtonTitle: "OK")

        a.show()
    }
}

Answer 1

抱歉，我沒有足夠的聲譽來發表評論，因此我將盡力回答您的問題。

該代碼似乎與Swift 2兼容。 我認為CoreData API尚未升級為利用新的do / try / catch語法進行錯誤處理，因此NSManagedObjectContext保存中的&error看起來不錯。

Answer 2

假設您的代碼是正確的，應該是這樣的：

做{

    try maContext.save()
    let a = UIAlertView(title: "Success", message: "Your Record is saved" , delegate: nil, cancelButtonTitle: "OK")
    a.show()
} catch let error as NSError {
    let a  = UIAlertView(title: "Error", message: err.localizedFailureReason, delegate: nil, cancelButtonTitle: "OK")
    a.show()
}

而不是您的代碼：

var error:NSError?

    maContext?.save(&error)

    if let err = error
    {
        let a  = UIAlertView(title: "Error", message: err.localizedFailureReason, delegate: nil, cancelButtonTitle: "OK")
        a.show()
    }
    else{
        let a = UIAlertView(title: "Success", message: "Your Record is saved" , delegate: nil, cancelButtonTitle: "OK")

        a.show()
    }