xcode Swift - 解除警报消息会关闭视图控制器
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Swift - Dismissing Alert Message Closes View Controller
提问by cphill
I have a registration process where I have an entry point with a Login/register with Facebook (Connected to Parse). If the user has never registered with their Facebook account, then they are sent to a send page where a user registers a username, email and password. I have a function setup that if a user leaves any of the text fields blank for the user registration, then a alert message appears with an error stating the field is blank. This functionality works correctly, but when I click "OK" to dismiss the message, the registration view controller dismisses itself and the entry point (login screen) view controller is displayed. This should not be happening and I don't have a segue setup to go from registration screen to login screen. Any thoughts?
我有一个注册过程，我有一个登录/注册 Facebook（连接到解析）的入口点。如果用户从未注册过他们的 Facebook 帐户，那么他们将被发送到用户注册用户名、电子邮件和密码的发送页面。我有一个功能设置，如果用户将用户注册的任何文本字段留空，则会出现一条警告消息，并显示一条错误消息，指出该字段为空。此功能正常工作，但当我单击“确定”关闭消息时，注册视图控制器自行关闭并显示入口点（登录屏幕）视图控制器。这不应该发生，我没有从注册屏幕到登录屏幕的 segue 设置。有什么想法吗？
One thing that pops out to me is the error in the console log, which I believe is actually associated with the Parse if/else statement, and not with the field == nil statement.
我突然想到的一件事是控制台日志中的错误，我认为这实际上与 Parse if/else 语句相关，而不是与 field == nil 语句相关联。
Console Log:
控制台日志：
2015-04-14 10:42:56.293 tappery[574:142525] [Error]: missing username (Code: 200, Version: 1.6.3)
Login Screen View Controller:
登录屏幕视图控制器：
import UIKit
class LoginViewController: UIViewController {
@IBOutlet var loginCancelledLabel: UILabel!
override func viewDidLoad() {
super.viewDidLoad()
// Do any additional setup after loading the view, typically from a nib.
var currentUser = PFUser.currentUser()
if currentUser != nil {
println("User is Logged in")
} else {
println("User is not logged in")
}
}
override func didReceiveMemoryWarning() {
super.didReceiveMemoryWarning()
// Dispose of any resources that can be recreated.
}
@IBAction func facebookLoginButton(sender: AnyObject) {
var permissions = ["public_profile", "email", "user_friends"]
self.loginCancelledLabel.alpha = 0
PFFacebookUtils.logInWithPermissions(permissions, {
(user: PFUser!, error: NSError!) -> Void in
if let user = user {
if user.isNew {
println("User signed up and logged in through Facebook!")
self.performSegueWithIdentifier("registerUser", sender: self)
} else {
println("User logged in through Facebook!")
self.performSegueWithIdentifier("loginSuccessful", sender: self)
}
} else {
println("Uh oh. The user cancelled the Facebook login.")
self.loginCancelledLabel.alpha = 1
}
})
}
}
Registration View Controller:
注册视图控制器：
import UIKit
class UserRegistrationViewController: UIViewController {
func displayAlert(title:String, error:String) {
var alert = UIAlertController(title: title, message: error, preferredStyle: UIAlertControllerStyle.Alert)
alert.addAction(UIAlertAction(title: "OK", style: .Default, handler: {
action in
self.dismissViewControllerAnimated(true, completion: nil)
}))
self.presentViewController(alert, animated: true, completion: nil)
}
@IBOutlet var usernameTextField: UITextField!
@IBOutlet var emailTextField: UITextField!
@IBOutlet var passwordTextField: UITextField!
override func viewDidLoad() {
super.viewDidLoad()
// Do any additional setup after loading the view.
}
override func didReceiveMemoryWarning() {
super.didReceiveMemoryWarning()
// Dispose of any resources that can be recreated.
}
@IBAction func registerUser(sender: AnyObject) {
var error = ""
if usernameTextField.text == nil || emailTextField.text == nil || passwordTextField.text == nil {
error = "Please enter a username, email and password"
}
if error != "" {
displayAlert("Error In Form", error: error)
} else {
var user = PFUser.currentUser()
user.username = usernameTextField.text
user.password = passwordTextField.text
user.email = emailTextField.text
user.saveInBackgroundWithBlock {
(succeeded: Bool!, signupError: NSError!) -> Void in
if signupError == nil {
println(user.username)
println(user.password)
println(user.email)
self.performSegueWithIdentifier("successfulRegistration", sender: self)
// Hooray! Let them use the app now.
} else {
if let errorString = signupError.userInfo?["error"] as? NSString {
error = errorString
} else {
error = "Please try again later."
}
self.displayAlert("Could Not Sign Up", error: error)
}
}
}
}
回答by zrzka
Remove self.dismissViewControllerAnimated(true, completion: nil)from your OK button UIAlertAction's handler. Alert is dismissed automatically upon OK button click and you're dismissing registration controller with this call.
删除self.dismissViewControllerAnimated(true, completion: nil)从您的OK按钮UIAlertAction的handler。单击“确定”按钮后会自动解除警报，并且您将通过此调用解除注册控制器。
