ios - 快速核心数据

Question

你好，我在 Swift 中遇到核心数据问题，这没有显示错误，但当我认为它应该在控制台中返回 'Joe' + 'pass' 时也不会打印任何内容。有谁能帮忙吗？

import UIKit
import CoreData

class ViewController: UIViewController {



override func viewDidLoad() {
    super.viewDidLoad()
    // Do any additional setup after loading the view, typically from a nib.

    var appDel:AppDelegate = UIApplication.sharedApplication().delegate as! AppDelegate

    var context:NSManagedObjectContext = appDel.managedObjectContext

    var newUser = NSEntityDescription.insertNewObjectForEntityForName("Users", inManagedObjectContext: context) as NSManagedObject

    newUser.setValue("Joe", forKey: "username")

    newUser.setValue("pass", forKey: "password")

    do {
     try context.save()
    } catch let error {
        print("Couldn't save user data")
        print(error)
    }

    let request = NSFetchRequest(entityName: "Users")
        request.returnsObjectsAsFaults = false

    do {
        var results = try context.executeFetchRequest(request)
        results = results as! [NSManagedObject]
        if results.count > 0 {
        for results in results {
            print(results)
            }}
    } catch let error as NSError {
        print(error)
    }
}

override func didReceiveMemoryWarning() {
    super.didReceiveMemoryWarning()
    // Dispose of any resources that can be recreated.
}


}

Answer 1

1. 您应该创建自己的核心数据类(作为 NSManagedObject 的子类)，然后从该类创建数组。

2. 准确指定您要打印的内容。在你的情况下

   newUser.username