在新的故事板中将值传递给 UIViewController - Swift

Posted 2023-03-13

【中文标题】在新的故事板中将值传递给 UIViewController - Swift

【英文标题】：Passing Values to UIViewController in new Storyboard - Swift

【发布时间】：2014-08-15 10:31:55

【问题描述】：

我正在尝试将值传递给新的视图控制器 - 位于新的故事板文件中。但是，当我这样做时，我从 NewViewController 得到的结果总是 nil。

以下是我在新故事板中显示视图控制器的方式：

// Show create account page with custom transition
var storyboard : UIStoryboard = UIStoryboard(name: StoryboardName, bundle: nil)
var vc : UIViewController = storyboard.instantiateViewControllerWithIdentifier(NewViewController) as UIViewController

我尝试在这里发送信息：

// Pass the delegate to the first view controller
let newViewController:NewViewController = NewViewController()
newViewController.createAccountDelegate = self
newViewController.teststring = "hello"

然后呈现视图控制器。

vc.transitioningDelegate = self
vc.modalTransitionStyle = UIModalTransitionStyle.CoverVertical
self.presentViewController(vc, animated: true, completion: nil)

这是我的 NewViewController，我尝试在其中接收值。但是最终仍然为零。

import UIKit

class NewViewController: UIViewController 
    var createAccountDelegate:AccountCreationDelegate!
    var teststring:NSString!

    override func viewDidLoad() 
        super.viewDidLoad()
    

我是否错误地发送了值？

【参考方案1】：

您正在使用此行创建NewViewController 的新实例

let newViewController:NewViewController = NewViewController()

而是分配变量并委托给您从StoryBoard 实例化的vc

var storyboard : UIStoryboard = UIStoryboard(name: StoryboardName, bundle: nil)
// It is instance of  `NewViewController` from storyboard 
var vc : NewViewController = storyboard.instantiateViewControllerWithIdentifier(NewViewController) as NewViewController

// Pass delegate and variable to vc which is NewViewController
vc.createAccountDelegate = self
vc.teststring = "hello"
vc.transitioningDelegate = self
vc.modalTransitionStyle = UIModalTransitionStyle.CoverVertical
self.presentViewController(vc, animated: true, completion: nil)

【讨论】：

为什么会发生这种情况，虽然它以前有效，但现在非常奇怪