Xcode更新到7.3后断言失败

Question

我将Xcode更新为7.3。在更新之前，我可以在运行代码时出现任何错误或崩溃。更新后，当我在iPhone上运行以下代码时，我得到了断言错误（有趣的是，模拟器上没有错误）。

let storyboard =  UIStoryboard(name: storyboard, bundle: nil)
self.window?.rootViewController = storyboard.instantiateInitialViewController() as UIViewController!

错误

2016-03-24 16:15:25.891 Zilingo[434:92251] *** Assertion failure in -[UIStoryboard instantiateViewControllerWithIdentifier:], /BuildRoot/Library/Caches/com.apple.xbs/Sources/UIKit/UIKit-3512.60.7/UIStoryboard.m:171
error: Execution was interrupted, reason: breakpoint 5.1.
The process has been returned to the state before expression evaluation.

我是不是错过了更新的某个步骤？

Answer 1

Try to this format:-   
func application(application: UIApplication, didFinishLaunchingWithOptions launchOptions: [NSObject: AnyObject]?) -> Bool {
   // get your storyboard
   let storyboard = UIStoryboard(name: "Main", bundle: nil)
   // instantiate your desired ViewController
   let rootController = storyboard.instantiateViewControllerWithIdentifier("MyViewController") as! UIViewController
   // Because self.window is an optional you should check it's value first and assign your rootViewController
   if let window = self.window {
      window.rootViewController = rootController
   }
   return true
}

Answer 2

我遇到了同样的问题。在我的情况下，我忘记添加标识符字符串。让vc=storyboard.instantiateViewControllerWithIdentifier（"）为！UIViewController

我像上面那样写的。我忘了添加标识符。在我添加标识符后，它就工作了。