Passing Data through multiple View Controllers with segue [Swift 3.0 Xcode] - swift

Question

NOTE: Question has been edited in an attempt to be more clear with my issue.
Hey, I am trying to pass data through multiple VCS. I want to pass data (arrays) from V2 -> V3 and then V3 -> V1 but I want to be able to only navigate through the VCs as such: V1 - V2 - V3 and V3 - V2 - V1.
So what I need to learn is how to pass data without navigating to a different VC as well as setting up two preparetosegue methods to pass data between V2 -> V3 and V3 -> V1 while also being able to navigate between all VCs. When I create my first preparetosegue, I am unable to use other segues associated in my VC to navigate to other VCs without getting a Fatal Error.
Can anyone help me?
Any input would be greatly appreciated!
Heres my attempt:
import UIKit
class ViewController: UIViewController {
var name = String()
var StopButInfo = [String]()
override func viewDidLoad() {
super.viewDidLoad()
// Do any additional setup after loading the view, typically from a nib.
}
override func didReceiveMemoryWarning() {
super.didReceiveMemoryWarning()
// Dispose of any resources that can be recreated.
}
}
import UIKit
class SecondViewController: UIViewController {
var StringArray = [String]()
override func viewDidLoad() {
super.viewDidLoad()
// Do any additional setup after loading the view.
}
#IBOutlet var PHeight: UITextField!
#IBOutlet var PName: UITextField!
#IBAction func Search(_ sender: Any) {
if PHeight.text != ""{
performSegue(withIdentifier: "SearchSegue", sender: self)}
let CDstart = String(describing: Date())
StringArray.append(CDstart)
StringArray.append(PName.text!)
StringArray.append(PHeight.text!)
}
override func prepare(for SearchSegue: UIStoryboardSegue, sender: Any?){
let thirdController = SearchSegue.destination as! ThirdViewController
thirdController.SearchButInfo = StringArray
}
override func didReceiveMemoryWarning() {
super.didReceiveMemoryWarning()
// Dispose of any resources that can be recreated.
}
}
import UIKit
class ThirdViewController: UIViewController {
var height = String()
var SearchButInfo = [String]()
var StringArray = [String]()
#IBAction func Stop(_ sender: Any) {
if StringArray.count != 0{
performSegue(withIdentifier: "SegueToStart", sender: self)
}
let CDStop = String(describing: Date())
StringArray.append(CDStop)
StringArray.append(height)
}
override func prepare(for SegueToStart: UIStoryboardSegue, sender: Any?){
let firstController = SegueToStart.destination as! ViewController
firstController.StopButInfo = StringArray}
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.
}
}

Answer 1

You need to check which view controller's segue is about to be performed, this can be done like this inside prepare(for segueMVH: UIStoryboardSegue, sender: Any?) method:
if let firstController = segueMVH.destination as! FirstViewController {
// Set first view controller's data
} else if let secondController = segueMVH.destination as! SecondViewController {
// Set second view controller's data
} else if let thirdController = segueMVH.destination as! ThirdViewController {
// Set third view controller's data
}
Note: It's better to use a different identifier for each segue to be able to distinguish between them.

Answer 2

The error you got on let secondController = segueMVH.destination as! ThirdViewController is saying that you are casing HC.ViewController into ThirdViewController and that's why it failed. It means that the destination view controller of your segue is not ThirdViewController.
To further help you understand segue: A segue is a connection between a source view controller and a destination view controller and can be only used between them two. See this picture:
In this case, I have a segue connection in my storyboard connected between my VC1's button and VC2. In this case, my button click will trigger this segue and prepare(for segue) method can only be in VC1 where it passes data to VC2.
So in your situation, you believe that the destination of your segue is ThirdViewController but it's actually not. So please check your segue with identifier segueMVH to see if it is connected between your current view controller and your ThirdViewController.
Hope this helps