Brand new to Objective-C. How do I listen to a variable in a different file?
===

As I said, brand new to Objective-C. I have a few years of experience in programming, though, and I'm a quick learner.

**General Issue**: I want to listen to a variable inside of a different file, then perform a certain action in response to changes to that variable. 

**Specific Issue**: I want to modify the way that the iPhone displays WiFi signal. Currently it has *4* states, but I want to make it have *8* states. My hope is to somehow listen to (or periodically read from) the variable *wifiSignalStrengthRaw* in SBStatusBarDataManager.h and then display it. 

**Question**: What's the best way to go about reading, or listening to, that variable? 

EDIT: *Secondary Question*: Is there a way to analyze code already compiled in Obj-C?