UIViewController failing to navigate to another page in swift - ios

Question

I have previously written this function and it was working fine. I started working on the project again after a week's break and the same code is not working. Am I missing something here? Basically if a button is pushed, checkCredentials will run. Everything in the "else" section is working completely fine, but the if user != nil section isn't working:
func checkCredentials (){
PFUser.logInWithUsernameInBackground(usernameLoginTxt.text!, password: passwordLoginTxt.text!){
(user:PFUser?, error:NSError?) -> Void in
if user != nil{
let storyboard: UIStoryboard = UIStoryboard(name: "Main", bundle: nil)
let vc: UIViewController = storyboard.instantiateViewControllerWithIdentifier("SearchViewController") as UIViewController
self.presentViewController(vc, animated: false, completion:nil)
NSLog("it was successfull dude")
}else{
let title = "Warning!"
let message = "You have entered the wrong username or password.\n Please try again!"
let okButton = "Ok"
let alert = UIAlertController(title: title, message: message, preferredStyle: UIAlertControllerStyle.Alert)
let okayButton = UIAlertAction(title: okButton, style: UIAlertActionStyle.Cancel, handler: nil)
alert.addAction(okayButton)
self.presentViewController(alert, animated: true, completion: nil)
}
}
}

Answer 1

This should work for you...
func login(){
let user = PFUser()
user.username = userNameText.text
user.password = passwordText.text
PFUser.logInWithUsernameInBackground(userNameText.text!, password: passwordText.text!, block: {
(user: PFUser?, Error: NSError?) -> Void in
if Error == nil {
dispatch_async(dispatch_get_main_queue()) {
let Storyboard = UIStoryboard(name: "Main", bundle: nil)
let AfterLoginVC: UIViewController = Storyboard.instantiateViewControllerWithIdentifier("AfterLoginVC") as! UINavigationController
self.presentViewController(AfterLoginVC, animated: true, completion: nil)
}
} else {
let title = "Warning!"
let message = "You have entered the wrong username or password.\n Please try again!"
let okButton = "Ok"
let alert = UIAlertController(title: title, message: message, preferredStyle: UIAlertControllerStyle.Alert)
let okayButton = UIAlertAction(title: okButton, style: UIAlertActionStyle.Cancel, handler: nil)
alert.addAction(okayButton)
self.presentViewController(alert, animated: true, completion: nil)
}
})
}
Also be sure that over the last week you didn't accidentally change your Parse client key (I've done that before) which will cause it to not show any error but simply to not work.