即使值存在，傳遞值也是零

Question

我試圖在viewControllers之間傳遞值。但問題是，價值總是零。

在firstVC我做的：

// 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) 

而在secondVC：

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

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

    } 

我與.xib做第一次，但我認爲這個概念應該是一樣的。

Answer 1

設置值selectedTestString創建對話框之前，這將解決問題。

// 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)