segue/push to different view controller from IBAction function? - swift

Question

I am trying to push to the next viewcontroller programatically, such that I can save data in core data and then push to the next view controller. Basically when I tap a button with an IBAction, it will do all this. However, I am getting a thread 1 SIGABRT error whenever I use this code in my IBAction func:
#IBAction func onPlusTapped(){
let alert = UIAlertController(title: "New Course", message: nil, preferredStyle: .alert)
alert.addTextField { (textField) in
textField.placeholder = "Course"
}
let action = UIAlertAction(title: "New", style: .default){ (_) in
let course = alert.textFields!.first?.text!
print(course)
let coursy = Course(context: PersistenceService.context)
coursy.name = course
PersistenceService.saveContext()
}
alert.addAction(action)
present(alert, animated: true, completion: nil)
// jump to next view controller
segway()
}
func segway(){
let storyBoard: UIStoryboard = UIStoryboard(name: "viewcontroller", bundle: nil)
let balanceViewController = storyBoard.instantiateViewController(withIdentifier: "viewcontroller") as! ViewController
self.present(balanceViewController, animated: true, completion: nil)
}
}

Answer 1

If you want to jump to your next viewController once Course saved, you have to call the func segway() in the UIAlertAction completion block.
Example:
let action = UIAlertAction(title: "New", style: .default){ (_) in
let course = alert.textFields!.first?.text!
print(course)
let coursy = Course(context: PersistenceService.context)
coursy.name = course
PersistenceService.saveContext()
// jump to next view controller
segway()
}
Also double check your storyboard name and balanceViewController's identifier is "viewcontroller".

Answer 2

Why are you jumping segway() and present alert at the same time? shouldn't you put segway() inside your alert action?
Please see the following code.
#IBAction func onPlusTapped() {
let alert = UIAlertController(title: "New Course", message: nil, preferredStyle: .alert)
alert.addTextField { (textField) in
textField.placeholder = "Course"
}
let action = UIAlertAction(title: "New", style: .default){ (_) in
let course = alert.textFields!.first?.text!
print(course)
let coursy = Course(context: PersistenceService.context)
coursy.name = course
PersistenceService.saveContext()
// jump to next view controller
segway()
}
alert.addAction(action)
present(alert, animated: true, completion: nil)
}
func segway() {
let storyBoard: UIStoryboard = UIStoryboard(name: "viewcontroller", bundle: nil)
let balanceViewController = storyBoard.instantiateViewController(withIdentifier: "viewcontroller") as! ViewController
self.present(balanceViewController, animated: true, completion: nil)
}
}
Hope this help!