Present a view controller from a closure - swift

Question

I have a closure as a handler for items that are added to a UIAlertController. I receive the id value inside the closure as expected. (I don't use it in the snippet).
But the problem that I have is that I want to switch to another view controller. But I do this call inside the closure.
I get the following error:
Value of type '(ChooseProfile) -> () -> (ChooseProfile)' has no member 'present'
How can I switch to another view controller from within my closure?
class ChooseProfile: UIViewController {
let closure = { (id: String) in { (action: UIAlertAction!) -> Void in
let storyBoard : UIStoryboard = UIStoryboard(name: "Main", bundle:nil)
let nextViewController = storyBoard.instantiateViewController(withIdentifier: "test") as! UIViewController
self.present(nextViewController, animated:true, completion:nil)
}}
}
I use this closure because of this:
override func viewDidAppear(_ animated: Bool) {
let alert = UIAlertController(title: "Choose a Device", message: "Which device would you like to use in this app?", preferredStyle: UIAlertControllerStyle.alert)
for dev in (DataSingleton.instance.getDevices())! {
alert.addAction(UIAlertAction(title: dev.getName(), style: UIAlertActionStyle.default, handler: closure(dev.getId())))
}
alert.addAction(UIAlertAction(title: "Add a new Profile", style: UIAlertActionStyle.destructive, handler: nil))
// show the alert
self.present(alert, animated: true, completion: nil)
}
I add the alert actions based on a list of devices. And I want to retrieve the id when I click on a device.

Answer 1

The problem is that you are using self in your closure, but that self doesn't refer to the instance of your VC because it hasn't been fully created yet. Instead, why not pass the viewController to the closure when you call it?
class ChooseProfile: UIViewController {
let closure = { (id: String, vc: UIViewController) in { [weak vc] (action: UIAlertAction!) -> Void in
let storyBoard : UIStoryboard = UIStoryboard(name: "Main", bundle:nil)
let nextViewController = storyBoard.instantiateViewController(withIdentifier: "test")
vc?.present(nextViewController, animated:true, completion:nil)
}}
}
override func viewDidAppear(_ animated: Bool) {
let alert = UIAlertController(title: "Choose a Device", message: "Which device would you like to use in this app?", preferredStyle: UIAlertControllerStyle.alert)
for dev in (DataSingleton.instance.getDevices())! {
alert.addAction(UIAlertAction(title: dev.getName(), style: UIAlertActionStyle.default, handler: closure(dev.getId(), self)))
}
alert.addAction(UIAlertAction(title: "Add a new Profile", style: UIAlertActionStyle.destructive, handler: nil))
// show the alert
self.present(alert, animated: true, completion: nil)
}