Implement own setter or use KVO?

Question

In short, when the property value changing, I have to update some logic in my code, for example:

- (void)setProp:(NSString *)theProp
{
  if (prop != theProp){
           


        

Answer 1

In your case the best option is to add the logic inside the setter. Your setter implementation is correct if your property declaration is something like

@property (nonatomic, copy) YCYourClass *prop;

KVO is used normally when checking for changes on external objects properties.

NSNotifications are better suited to inform of events.