ios-“failed to instantiate the default view controller for uimainstoryboardfile ‘main’ – perhaps the designated entry point is not set?”

问题：Failed to instantiate the default view controller for UIMainStoryboardFile 'Main' - perhaps the designated entry point is not set?
原因分析：在StoryBoard中没有一个view controller设置了Initial Scene，往往由于删除了最初的ViewVontroller而发生。

解决方案：在Storyboard中，选择一个view conroller作为story board的第一启动界面。