How do you find out what current active application you are in or if you are in the springboard's homepages?

How would one go about modifying individual assembly instructions in an application while it is running? I have a Mobile Substrate tweak that I am writing for an existing application. In the tweak'...

From objc sources we can see that SEL is defined as typedef struct objc_selector *SEL; I have disassembly my dylib with idaq, and I did finde call of _MSHookMessageEx function, that is linked from...