design patterns - difference between Target Action and Key Value Observer in iOS -

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what difference between two? me both doing same thing i.e notify event observer event.

i read post http://www.raywenderlich.com/46988/ios-design-patterns regarding actual pattern in use 2 above mentioned event handling techniques failed understand how command pattern different observer pattern or missing something.

my understanding of them next: in case of target action, have notification center through pass info between 2 classes. have 1 class sends out notification notification center broadcast info , second class has observers listen broadcast matches criteria.

while in case of kvo have object capable of observing change of 1 of it's properties. no 1 posting notification in case of kvo. hope cleared things @ least bit.


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