December 2013
Intermediate to advanced
132 pages
1h 58m
English
Content preview from Objective-C Quick Syntax ReferenceBecome an O’Reilly member and get unlimited access to this title plus top books and audiobooks from O’Reilly and nearly 200 top publishers, thousands of courses curated by job role, 150+ live events each month,
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CHAPTER 22
Key-Value Observation
Key-Value Observation Defined
One of the applications of key-value coding is implementing the observer pattern. The observer pattern is used when you want an object to get a notification when the state of another object changes. This pattern is implemented with key-value observation in Objective-C.
To see a clear example of key-value observation, you need at least two objects. One object will be observed while the other object will be observing. For this example, let’s assume that you have two types of objects: a Project object and a Task object. Project objects maintain a list of Task objects. The project object ...
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I wanted to learn C and C++, but it didn't click for me until I picked up an O'Reilly book. When I went on the O’Reilly platform, I was astonished to find all the books there, plus live events and sandboxes so you could play around with the technology.Addison B.
I’ve been on the O’Reilly platform for more than eight years. I use a couple of learning platforms, but I'm on O'Reilly more than anybody else. When you're there, you start learning. I'm never disappointed.Amir M.
I'm always learning. So when I got on to O'Reilly, I was like a kid in a candy store. There are playlists. There are answers. There's on-demand training. It's worth its weight in gold, in terms of what it allows me to do.