ios - Disable Key-Value Observing in Objective C -


i don't use kvo, performance reasons, make sure disable properly.

from apple key-value observing programming guide

automatic support (for kvo) provided nsobject , default available properties of class key-value coding compliant. typically, if follow standard cocoa coding , naming conventions, can use automatic change notifications—you don’t have write additional code.

is mean every property generated xcode has willchangevalueforkey , didchangevalueforkey methods implemented?

if there way (some flag or something) disable behaviour? i'm using accessinstancevariablesdirectly , returning no, i'm not sure if enough.

i don't use kvo.

you cannot know that. cocoa framework classes or other foreign code might depend on kvo without knowledge.

also, nsobject's kvo uses technique called isa-swizzling automatically augment observed objects dynamically subclassing them. means there's no overhead on objects not observed.

your other questions:

accessinstancevariablesdirectly used in kvc only, , not connected kvo. there's no performance benefit in overriding it.

does mean every property generated xcode has willchangevalueforkey , didchangevalueforkey methods implemented?

yes, every object responds these methods. presence of these methods again not mean performance affected in way. methods not called.


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