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Popularfan
Asked: 2020-01-31 15:10:14 +0800 CST 2020-01-31 15:10:14 +0800 CST

Passing parameters from a child viewController to a parent after doing a dismiss

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From a parent controller I call another child ( popoverContent )with self.present, the child controller is a typical view in the form of a popup that at the end I close with a dismiss but I want to pass some data to the parent view.

Called within the code of the parent controller:

self.present(popoverContent, animated: true, completion: nil )

I close the child view ( popoverContent) with a button action

@IBAction func exitButtonAction(_ sender: Any) {
        self.dismiss(animated: true, completion: nil)
    }

How can I pass a parameter of type String, or Int, or dictionary to the parent view after closing the child view with dismiss ?

ios

2 Answers

  1. Passing data from a child ViewController to a parent can be done by a protocol hosted on the parent and "manipulated" by the child but I find it can be a bit of a hassle to implement these functions.

    One way you can manipulate your variables is to: 1. Create a class in which you store the data you need. 2. Create a static variable to access said class from any controller without having to create a new object of this same class. 3. Implement set and get to be able to access your data.

    Something like this:

    class almacenamiento: NSObject
{
    static let sharedInstance = almacenamiento()
    var dato1: String?

    override init() {
        super.init()
    }

    public func set_value(nuevoValor: String)
    {
        self.dato1 = nuevoValor
    }

    public func get_value() -> String?
    {
        return self.dato1
    }
}

    The way you can retrieve the information is, for example from the viewWillAppear() method:

    override func viewWillAppear(_ animated: Bool) {
        super.viewWillAppear(animated)

        almacenamiento.sharedInstance.set_value(nuevoValor: "Hola mundo")
        if let value = almacenamiento.sharedInstance.get_value()
        {
            print("\nValor por medio de metodo get: \(value)")
        }

        if let value = almacenamiento.sharedInstance.dato1
        {
            print("Valor extraido directamente de la clase: \(value)\n")
        }
    }

    Prints: Value through get method: Hello world Value extracted directly from the class: Hello world

    • 1
  2. Best Answer

    The most logical thing would be to make a protocol, you can look at this: protocols, passing information from other views to one from an action

    But if what you want is something simpler, and you are going to pass a couple of variables, you can apply the same concept as a delegate. In popoverContent you create a var that is of the type of the parent, you create the popoverContent, to that variable you assign the value of the parent, you show it and before closing it, popoverContent has a reference to the parent, so I could modify the parent variable that you would like

    In the popoverContent:

    var padre: ClaseQueMeLlama?

    In parent, you create and assign:

    //init del popoverContent
let popoverContent = popoverContent(........)
popoverContent.padre = self
self.present(popoverContent, animated: true, completion: nil )

    By the time you go to close the popover:

    @IBAction func exitButtonAction(_ sender: Any) {
    //aqui le pasas los valores que quieras al padre, que tendrán que estar definidos y ser public
    self.padre?.foo = self.foo
    self.dismiss(animated: true, completion: nil)
}
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