ios - 从函数返回数据 (Swift)

Question

我正在尝试返回结果并能够从此函数访问结果数组。一切都在函数中工作，但是我不能返回任何东西或访问结果或从闭包外部在函数内部创建的任何变量。我想从闭包外部访问 result.valueForKey("id") 。我该怎么做？

class ViewController: UIViewController, FBSDKLoginButtonDelegate {

var facebookid: NSString = ""
var username: NSString = ""
var userEmail:NSString = ""

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

    if (FBSDKAccessToken.currentAccessToken() == nil)
    {
        let loginView : FBSDKLoginButton = FBSDKLoginButton()
        self.view.addSubview(loginView)
        loginView.center = self.view.center
        loginView.readPermissions = ["public_profile"]
        loginView.delegate = self

    } else {

        returnUserData()

        println(facebookid)  // This doesn't work

    }
}



    func returnUserData()
{

    let graphRequest : FBSDKGraphRequest = FBSDKGraphRequest(graphPath: "me", parameters: nil)
    graphRequest.startWithCompletionHandler({ (connection, result, error) -> Void in

        if ((error) != nil)
        {
            // Process error
            println("Error: \(error)")
        }
        else
        {

            self.facebookid = result.valueForKey("id") as NSString!
            self.username = result.valueForKey("name") as NSString!
            self.userEmail = result.valueForKey("email") as NSString!
            println(result) // This works


        }
    })
}

编辑:我确实根据下面的 2 个答案更改了代码，但我仍然无法在 viewDidLoad 闭包上获得任何数据返回。* println(facebookid) 在 ViewDidLoad 中不返回任何内容，而在函数的闭包内返回任何内容。

Answer 1

您在闭包内创建变量意味着它们只能在内部访问。

您需要在类的顶部在函数外部创建变量。

例如

 class YourClassName {

      var facebookid
      var username
      var userEmail


 func returnUserData()
 {
     let graphRequest : FBSDKGraphRequest = FBSDKGraphRequest(graphPath:  "me", parameters: nil)
     graphRequest.startWithCompletionHandler({ (connection, result, error) -> Void in

    if ((error) != nil)
    {
        // Process error
        println("Error: \(error)")
    }
    else
    {
        self.facebookid = result.valueForKey("id") as? String
        self.userName = result.valueForKey("name") as? String
        self.userEmail = result.valueForKey("email") as? String

    }
  })
 }
}