Application Bug

Application windows are expected to have a root view controller at the end of application launch

• 从iOS9开始, 在程序启动完毕那一刻显示出来的窗口必须要设置根控制器

*** Terminating app due to uncaught exception 'NSInternalInconsistencyException', reason: 'There can only be one UIApplication instance.'

• 由于异常终止应用程序“NSInternalInconsistencyException”,原因是:“UIApplication只能有一个单例。