我遇到了同样的问题 - 你是否正在使用swift？注释掉init（nibName nibNameOrNil：String？，bundle nibBundleOrNil：NSBundle？）函数，如本回复中所建议的那样为我修复了它：
iOS 8 Beta Today扩展小部件未在Swift应用中显示？

Trying to run my iOS widget that is a "Today" extension. Every time i try to add it to the notification center, i keep getting the message "Terminating since there is no System App

Any ideas on how to fix this?

Im trying to make an extension that has a tableview in it

I was having the same problem - Are you using swift? Commenting out the "init(nibName nibNameOrNil: String?, bundle nibBundleOrNil: NSBundle?)" function as suggested in this response fixed it for me: iOS 8 Beta Today extension widget not showing in a Swift app?