Is it at all possible, from within an AsyncTask that is NOT an inner class of the calling Activity class, to get a reference to the instance of Activity that initiated execution of the AsyncTask?

I am aware of this thread, however it doesn't exactly address how to reference the calling Activity. Some suggest passing a reference to the Activity as a parameter to the AsyncTask constructor, however, it's reported that doing so will always result in a NullPointerException.

So, I'm at a loss. My AsyncTask provides robust functionality, and I don't want to have to duplicate it as an inner class in every Activity that wants to use it. There must be an elegant solution.