What is KVO used for?

KVO, which stands for Key-Value Observing, is one of the techniques for observing the program state changes available in Objective-C and Swift. The concept is simple: when we have an object with some instance variables, KVO allows other objects to establish surveillance on changes for any of those instance variables.

What is KVO and KVC in Swift?

KVO and KVC or Key-Value Observing and Key-Value Coding are mechanisms originally built and provided by Objective-C that allows us to locate and interact with the underlying properties of a class that inherits NSObject at runtime.

What does KVO stand for in Objective C?

The concept KVO, which stands for Key-Value Observing, is one of the techniques for observing the program state changes available in Objective-C and Swift. The concept is simple: when we have an object with some instance variables, KVO allows other objects to establish surveillance on changes for any of those instance variables.

How is KVO related to Key Value Coding?

This method is called Key-Value Observing, but is mostly known as KVO. Key-Value Observing (KVO) is related directly to another powerful and important mechanism, named Key-Value Coding, or KVC. Actually, any property you want to observe for changes must be Key-Value Coding compliant, but we will talk more about that later.

How does KVO get you at the end?

Perhaps the most pronounced annoyance with KVO is how it gets you at the end. If you make a call to –removeObserver:forKeyPath:context: when the object is not registered as an observer (whether because it was already unregistered or not registered in the first place), an exception is thrown.

Which is the code example for KVO in Swift?

For the KVO code example in Swift jump stright to the KVO in Swift section. KVO, which stands for Key-Value Observing, is one of the techniques for observing the program state changes available in Objective-C and Swift.