无法迅速在视图控制器之间传递值

Question

I have two viewcontrollers, I have to pass values from the second vc to the first vc. That is, have to append the string nameText in the array nameArray , which is in my firstvc. This is what I'm doing in my secondvc:

let homeViewController: HomeViewController = storyboard?.instantiateViewController
(withIdentifier: "homeViewControllerIdentifier") as! HomeViewController
homeViewController.nameArray.append(nameText)

I put a break point in the last statement above^ and do po homeViewController.nameArray.first I get the value. But when I do the same when the control goes back to the first vc, And I try and use the array, is says it is nil . I thought in this line, homeViewController.nameArray.append(nameText) , I'm adding a value inside an array? What is wrong in this? Thanks in advance.

Answer 1

Reason why your code isn't working because you're instantiating the old viewcontroller and creating a new instance of it.

You need to create a delegate/protocol here. Something like:

    protocol ViewDelegate{
       func updateArray()
    }

    class Class1: UIViewController{

    override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
        let vc = segue.destinationController as! Class2
        vc.delegate = self
    }
     }    
    extension Class1: ViewDelegate {

    func updateArray(){
    // update array here
       }
    }

    class Class2: UIViewController{
    var delegate: ViewDelegate!

     func updatearrayhere(){
        delegate.updateArray()
       }    

    }