我的performSegueWithIdentifier方法的实现不是启动segue。
我尝试通过在方法之前和之后放置print语句来进行调试:它在之前打印,而不是之后打印,这显然表明该方法不起作用,对吧?
class ViewController: UIViewController{
var signupActive = true
@IBOutlet weak var username: UITextField!
@IBOutlet weak var password: UITextField!
var errorMessage = "Please try again later"
func displayAlert(title: String, message: String) {
let alert = UIAlertController(title: title, message: message, preferredStyle: UIAlertControllerStyle.Alert)
alert.addAction((UIAlertAction(title: "Ok", style: .Default, handler: { (action) -> Void in
self.dismissViewControllerAnimated(true, completion: nil)
})))
self.presentViewController(alert, animated: true, completion: nil)
}
@IBAction func signUp(sender: AnyObject) {
if username.text == "" || password.text == "" {
displayAlert("Error in form", message: "Please enter a username and password")
} else {
UIApplication.sharedApplication().beginIgnoringInteractionEvents()
var errorMessage = "Please try again later"
if signupActive == true {
var user = PFUser()
user.username = username.text
user.password = password.text
user.signUpInBackgroundWithBlock({ (success, error) -> Void in
UIApplication.sharedApplication().endIgnoringInteractionEvents()
if error == nil {
// Right here and below as well
self.performSegueWithIdentifier("login", sender: self)
} else {
if let errorString = error!.userInfo["error"] as? String {
errorMessage = errorString
}
self.displayAlert("Failed signup", message: errorMessage)
}
})
} else {
PFUser.logInWithUsernameInBackground(username.text!, password: password.text!, block: { (user, error) -> Void in
UIApplication.sharedApplication().endIgnoringInteractionEvents()
if user != nil {
// Here too
print("kay")
self.performSegueWithIdentifier("login", sender: self)
print("yay")
} else {
if let errorString = error!.userInfo["error"] as? String {
errorMessage = errorString
}
self.displayAlert("Failed login", message: errorMessage)
}
})
}
}
}
答案 0 :(得分:3)
您需要在主线程上执行segue,因为当前您正在块中执行segue。
在主线程上执行你的segue:
dispatch_async(dispatch_get_main_queue()){
self.performSegueWithIdentifier("login", sender: self)
}