您返回null的原因是您无法访问它。这实际上不是一个bug。根据Apple指南，某些API不适用于iOS 8扩展（请参阅下面的子弹＃3）。

The reason you're getting back null is because you don't have access to it. It's actually not a bug. According to Apple guidelines certain APIs are not available to iOS 8 extensions (See bullet #3 below).

这很糟糕，但我总是鼓励人们阅读新功能，看看他们想做什么是可能的，然后再进入一个想法（节省了大量时间）。绝对查看应用程序扩展编程指南了解更多信息。

It sucks, but I always encourage people to read up on new features and see if what they want to do is possible, before dwelling into an idea (Saves a lot of time). Definitely check out the App Extension Programming Guide for more information.