Book Image

Learning Swift Second Edition - Second Edition

By : Andrew J Wagner
Book Image

Learning Swift Second Edition - Second Edition

By: Andrew J Wagner

Overview of this book

Swift is Apple’s new programming language and the future of iOS and OS X app development. It is a high-performance language that feels like a modern scripting language. On the surface, Swift is easy to jump into, but it has complex underpinnings that are critical to becoming proficient at turning an idea into reality. This book is an approachable, step-by-step introduction into programming with Swift for everyone. It begins by giving you an overview of the key features through practical examples and progresses to more advanced topics that help differentiate the proficient developers from the mediocre ones. It covers important concepts such as Variables, Optionals, Closures, Generics, and Memory Management. Mixed in with those concepts, it also helps you learn the art of programming such as maintainability, useful design patterns, and resources to further your knowledge. This all culminates in writing a basic iOS app that will get you well on your way to turning your own app ideas into reality.
Table of Contents (19 chapters)
Learning Swift Second Edition
Credits
About the Author
About the Reviewer
www.PacktPub.com
Preface
Index

Refactoring to respect model-view-controller


We have already made some good progress on the core functionality of our app. However, before we move any further, we should reflect on the code we have written. Ultimately, we haven't actually written that many lines of code, but it can definitely be improved. The biggest shortcoming of our code is that we have put a lot of business logic inside our view controller. This is not a good separation of our different model, view, and controller layers. Let's take this opportunity to refactor this code into a separate type.

We will create a class called PhotoStore that will be responsible for storing our photos and that will implement the data source protocol. This will mean moving some of our code out of our view controller.

First, we will move the photo's property to the photo store class:

import UIKit

class PhotoStore: NSObject {
    var photos = [Photo]()
}

Note that this new photo store class inherits from NSObject. This is necessary for us to be...