核心数据问题Swift [英] Core data issue Swift

问题描述

您好我目前正在关注一个使用旧版本的Swift的Swift教程，我无法跟随这个，因为我相信在新版本的Swift中的语法已经改变。

Hello I am currently following a Swift tutorial which uses the old version of Swift and I am not able to follow this as I believe the syntax has changed in the newer version of Swift.

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
      //  var results = context.executeFetchRequest(request)

    do {
        var results =
            try context.executeFetchRequest(request)
        results = results as! [NSManagedObject]
    } catch let error as NSError {
        print(error)
    }

    for result: AnyObject in results {
        print(results)
    }
}

我收到的错误是与结果在结果的行：AnyObject在结果和错误是未解决的标识符'结果'，这让我的印象是，这应该声明某处作为一个变量，因为它目前未解决，但我不知道如何解决这个，任何帮助非常感谢！

The error I am receiving is to do with the results on the line for result: AnyObject in results and the error is unresolved identifier 'results' which is giving me the impression that this should be declared somewhere as a variable as it is currently unresolved but I cannot figure out how to fix this, any help would be greatly appreciated, thanks!

推荐答案

do {
    var results = try context.executeFetchRequest(request)
    results = results as! [NSManagedObject]
} catch let error as NSError {
    print(error)
}

for result: AnyObject in results {
    print(results)
}

范围内的 do 块。您需要在 do 中移动数组的处理：

results only has scope inside the do block there. You need to move the processing of the array inside the do:

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

也不需要通过投射丢失信息 AnyObject 。

Also there's no need to lose information by casting as AnyObject.

这篇关于核心数据问题Swift的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！