Top "Key-value-observing" questions

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

Observing Changes to a mutable array using KVO vs. NSNotificationCenter

In my model I have an array of objects called events. I would like my controller to be notified whenever …

ios model-view-controller delegates key-value-observing nsnotificationcenter
How to detect a property return type in Objective-C

I have an object in objective-c at runtime, from which I only know the KVC key and I need to …

objective-c runtime properties types key-value-observing
When should I remove observers? Error about deallocating objects before removing observers

I am trying to use key-value observing in one of my classes. I register the observers in the init method …

objective-c cocoa-bindings observer-pattern key-value-observing
Best practices for context parameter in addObserver (KVO)

I was wondering what you should set the Context pointer in KVO when you are observing a property. I'm just …

objective-c key-value-observing
Send Notification When a Property is Changed Using KVO

I had a property named myName in my class, like: @property (nonatomic, strong) NSString *myName; I need to send a …

ios objective-c properties key-value-observing
How to be notified when a UIView detached from its superView?

It seems that the UIView has not methods like "didRemoveFromSuperview" or "willRemoveFromSuperview".Then,How to listen to the event when …

ios iphone uiview key-value-observing
Key Value Observing with an NSArray

I've looked on SO for examples of using Key Value Observing with an NSArray (or NSMutableArray) and apparently you need …

iphone objective-c nsarray key-value-observing nsarraycontroller
Understanding KVO in iOS

Regarding "Ensuring KVO Compliance", there are some official definition which seem like hard to understand In order to be considered …

ios key-value-observing
"message was received but not handled" KVO

I'm getting the following in my output window when running a project: An -observeValueForKeyPath:ofObject:change:context: message was received …

objective-c key-value-observing
What's wrong with this observeValueForKeyPath:ofObject:change:context: implementation?

In my UIScrollView subclass, I'm observing frame changes: [self addObserver:self forKeyPath:@"frame" options:0 context:NULL]; My observeValueForKeyPath:ofObject:change:…

ios key-value-observing