Top "Key-value-observing" questions

Key-value Observing or KVO is a technology for observing changes in object properties.

Is key-value observation (KVO) available in Swift?

If so, are there any key differences that weren't otherwise present when using key-value observation in Objective-C?

swift key-value-observing
How can I do Key Value Observing and get a KVO callback on a UIView's frame?

I want to watch for changes in a UIView's frame, bounds or center property. How can I use Key-Value Observing …

iphone ios objective-c uiview key-value-observing
How can i tell if an object has a key value observer attached

if you tell an objective c object to removeObservers: for a key path and that key path has not been …

objective-c cocoa key key-value-observing
What's the best way to communicate between view controllers?

Being new to objective-c, cocoa, and iPhone dev in general, I have a strong desire to get the most out …

objective-c iphone cocoa-touch delegates key-value-observing
Observing an NSMutableArray for insertion/removal

A class has a property (and instance var) of type NSMutableArray with synthesized accessors (via @property). If you observe this …

cocoa key-value-observing key-value-coding
Why would you use an ivar?

I usually see this question asked the other way, such as Must every ivar be a property? (and I like …

objective-c ios memory-management key-value-observing ivar
NSDictionary setValue:

OK, this is driving me nuts -- please tell me I'm not losing my mind! I declare: NSMutableDictionary* generalSettingsDict; im …

objective-c debugging key-value-observing nsmutabledictionary key-value-coding
KVO - How to check if an object is an observer?

When observing a value on an object using addObserver:forKeyPath:options:context:, eventually you'll want to call removeObserver:forKeyPath: on …

objective-c ios key-value-observing
Simple KVO example

I am trying to do simple KVO example, but I am having problems. This is my *.m file: #import "KVO_…

ios objective-c key-value-observing
Observing change in UIDatePicker

I noticed that there is no delegate to observe changes in UIDatePicker. Is there a way to detect when a …

objective-c ios uidatepicker key-value-observing