關於[UIApplication _runWithMainScene:transitionContext:completion:]的錯誤

錯誤提示:

Assertion failure in-[UIApplication _runWithMainScene:transitionContext:completion:], /BuildRoot/Library/Caches/com.apple.xbs/Sources/UIKit/UIKit-3505.16/UIApplication.m:3294**

原因：

• Xcode7需要所有UIWindow必須有一個rootViewController

解決辦法：

UIWindow*window=[[UIWindowalloc]initWithFrame[UIScreenmainScreen].bounds];
window.rootViewController = [UIViewController new];