ios - 即使值确实存在，传递值也会返回 nil

Question

我尝试在 viewController 之间传递值。但问题是，该值始终为零。

在 firstVC 中我这样做:

// Create a custom view controller
let ratingVC = RatingViewController(nibName: "RatingView", bundle: nil)

// Create the dialog
let popup = PopupDialog(viewController: ratingVC, buttonAlignment: .horizontal, transitionStyle: .bounceDown, gestureDismissal: true)

ratingVC.selectedTestString = "HELLO"


// Present dialog
self.present(popup, animated: true, completion: nil)

在第二个 VC 中:

var selectedTestString: String! //Unwrapping because I know value does exist

override func viewDidLoad() {
        super.viewDidLoad()
    print(selectedTestString) //Gives nil

    }

我是第一次用 .xib 做，但我认为概念应该是一样的。

Answer 1

在创建对话框之前设置 selectedTestString 的值，这将解决问题。

// Create a custom view controller
let ratingVC = RatingViewController(nibName: "RatingView", bundle: nil)

ratingVC.selectedTestString = "HELLO"

// Create the dialog
let popup = PopupDialog(viewController: ratingVC, buttonAlignment: .horizontal, transitionStyle: .bounceDown, gestureDismissal: true)

// Present dialog
self.present(popup, animated: true, completion: nil)