[NSObject：AnyObject]？'在Xcode 6 Beta 6中没有名为'subscript'的成员 [英] [NSObject : AnyObject]?' does not have a member named 'subscript' in Xcode 6 Beta 6

问题描述

我正在使用Swift中的Xcode 6 Beta 6构建应用程序并且我一直收到此错误：

  [NSObject：AnyObject ]？'没有名为'下标'的成员
  

我不知道如何解决这个问题。我试过看这个 [NSObject ：AnyObject]？'在Xcode 6 beta 6中没有名为'subscript'的成员但我仍然不明白这是如何解决问题的。如果有人可以向我解释，那将是非常好的。如果你想查看我的代码，这里是：

  import UIKit 
 
 class TimelineTableViewController：UITableViewController {
 
覆盖func viewDidAppear（动画：Bool）{
 
 if（（PFUser.currentUser（））！= nil）{
 
 //如果没有用户
 var loginAlert，则创建一个UIAlertController：UIAlertController = UIAlertController（标题：注册/登录，消息：请注册或登录，preferredStyle：UIAlertControllerStyle.Alert）
 
 //在登录警报中为用户名添加textView 
 loginAlert.addTextFieldWithConfigurationHandler（{
 textfield in 
 textfield.placeholder =Your Username
 }）
 
 //在登录警报中添加一个textView以获取密码
 loginAlert.addTextFieldWithConfigurationHandler（{
 textfield in 
 textfield.placeholder =Your Password 
 textfield.se cureTextEntry = true 
}）
 
 //将用户输入放入数组并相应地设置用户名和密码登录
 loginAlert.addAction（UIAlertAction（标题：登录，样式：UIAlertActionStyle.Default，处理程序：{
 alertAction in 
 let textFields：NSArray = loginAlert.textFields as NSArray 
 let usernameTextfield：UITextField = textFields.objectAtIndex（0）as UITextField 
 let passwordTextfield：UITextField = textFields.objectAtIndex（1）as UITextField 
 
 PFUser.logInWithUsernameInBackground（usernameTextfield.text，password：passwordTextfield.text）{
（user：PFUser！，error ：NSError！） - >在
中无效if（（user）！= nil）{
 println（Login successfull）
} else {
 println（登录失败 ）
} 
 
 
} 
 
}））
 
 //将用户输入放入数组并相应地设置用户名和密码以注册
 loginAlert.addAction（UIAlertAction（标题：注册，样式：UIAlertActionStyle.Default，处理程序：{
 
中的alertAction让textFields：NSArray = loginAlert.textFields as NSArray 
 let usernameTextfield：UITextField = textFields.objectAtIndex（0）as UITextField 
 let passwordTextfield：UITextField = textFields.objectAtIndex（1）as UITextField 
 
 var sweeter：PFUser = PFUser（）
 sweeter.username = usernameTextfield.text 
 sweeter.password = passwordTextfield.text 
 
 sweeter.signUpInBackgroundWithBlock {
（成功：Bool！，错误：NSError！） - >如果！（错误！=无），
无效{
 println（注册成功）
 } else {
 let errorString = error.userInfo [erro r] as NSString 
 println（errorString）
} 
 
 
} 
 
}））
} 
} 
 
覆盖func viewDidLoad（）{
 super.viewDidLoad（）
 
 //取消注释以下行以保留演示文稿之间的选择
 // self.clearsSelectionOnViewWillAppear = false 
 
 //取消注释以下行以在此视图控制器的导航栏中显示编辑按钮。 
 // self.navigationItem.rightBarButtonItem = self.editButtonItem（）
} 
 
覆盖func didReceiveMemoryWarning（）{
 super.didReceiveMemoryWarning（）
 / /处置可以重新创建的任何资源。 
} 
  

以下是发生错误的地方：

<请告诉我为什么会这样。谢谢！

解决方案

错误消息说你做不到 [] on 可选值。您需要做的就是打开它。

  error.userInfo！[error] as NSString 
  

或者如果你想要安全

 如果让errorString = error.userInfo？[error]为NSString {
 println（errorString）
} 
  

I am building an app in Xcode 6 Beta 6 in Swift and I keep getting this error:

[NSObject : AnyObject]?' does not have a member named 'subscript'

I have no idea how to fix this. I have tried looking at this [NSObject : AnyObject]?' does not have a member named 'subscript' error in Xcode 6 beta 6 but I still don't understand how that solves the problem. If someone could explain that to me, that would be very nice. If you want to see my code, here it is:

import UIKit

class TimelineTableViewController: UITableViewController {

 override func viewDidAppear(animated: Bool) {

    if ((PFUser.currentUser()) != nil) {

        //Create an UIAlertController if there isn't an user
        var loginAlert:UIAlertController = UIAlertController(title: "Sign Up/ Log In", message: "Please sign up or log in", preferredStyle: UIAlertControllerStyle.Alert)

        //Add a textView in the Log In Alert for the username
        loginAlert.addTextFieldWithConfigurationHandler({
            textfield in
            textfield.placeholder = "Your Username"
        })

        //Add a textView in the Log In Alert for the password
        loginAlert.addTextFieldWithConfigurationHandler({
            textfield in
            textfield.placeholder = "Your Password"
            textfield.secureTextEntry = true
        })

        //Place the user-input into an array and set the username and password accordingly for Log In
        loginAlert.addAction(UIAlertAction(title: "Login", style: UIAlertActionStyle.Default, handler: {
            alertAction in
            let textFields:NSArray = loginAlert.textFields as NSArray
            let usernameTextfield:UITextField = textFields.objectAtIndex(0) as UITextField
            let passwordTextfield:UITextField = textFields.objectAtIndex(1) as UITextField

            PFUser.logInWithUsernameInBackground(usernameTextfield.text, password: passwordTextfield.text){
                (user:PFUser!, error:NSError!)->Void in
                if ((user) != nil){
                    println("Login successfull")
                }else{
                    println("Login failed")
                }


            }

        }))

        //Place the user-input into an array and set the username and password accordingly for Sign Up
        loginAlert.addAction(UIAlertAction(title: "Sign Up", style: UIAlertActionStyle.Default, handler: {
            alertAction in
            let textFields:NSArray = loginAlert.textFields as NSArray
            let usernameTextfield:UITextField = textFields.objectAtIndex(0) as UITextField
            let passwordTextfield:UITextField = textFields.objectAtIndex(1) as UITextField

            var sweeter:PFUser = PFUser()
            sweeter.username = usernameTextfield.text
            sweeter.password = passwordTextfield.text

            sweeter.signUpInBackgroundWithBlock{
                (success:Bool!, error:NSError!)->Void in
                if !(error != nil){
                    println("Sign Up successfull")
                }else{
                    let errorString = error.userInfo["error"] as NSString
                    println(errorString)
                }


            }

        }))
    }
}

override func viewDidLoad() {
    super.viewDidLoad()

    // Uncomment the following line to preserve selection between presentations
    // self.clearsSelectionOnViewWillAppear = false

    // Uncomment the following line to display an Edit button in the navigation bar for this view controller.
    // self.navigationItem.rightBarButtonItem = self.editButtonItem()
}

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

Here is where the error is occuring:

Please tell me why this is occurring. Thanks!

解决方案

The error message is saying you can't do [] on Optional value. What you need to do is unwrap it.

error.userInfo!["error"] as NSString

or if you want to be safe

if let errorString = error.userInfo?["error"] as NSString {
     println(errorString)
}

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