Question

how can I set up my code so that I set up a listener on an integer variable, so that when the value changes (the value is binded to an object), the notification is called?
Thanks!

Answer 1

You cannot detect the change of a plain C variable.

You probably want to observe a change of an object’s internal state. If so, you should wrap the integer value into a property and use accessor methods to modify the value.

@interface Foo : NSObject
@property int bar; // declares a property of type int
@end

@implementation Foo
@synthesize bar; // creates accessor methods for the property
@end

Changes to properties can be detected using Key Value Observing.