Jesse Feiler - Swift For Dummies

1. Table of Contents

Swift For Dummies

Published by: John Wiley & Sons, Inc., 111 River Street, Hoboken, NJ 07030-5774, www.wiley.com

Copyright 2015 by John Wiley & Sons, Inc., Hoboken, New Jersey

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Published simultaneously in Canada

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Library of Congress Control Number: 2014954655

ISBN 978-1-119-02222-0 (pbk); ISBN 978-1-119-02224-4(ebk); ISBN 978-1-119-02223-7 (ebk)

In June of 2014, one of the highlights of Apples Worldwide Developers Conference (WWDC) was the announcement a surprise to many attendees, including the multitudes of developers watching the videos around the world of the development of a new language aimed at developers to use with iOS and OS X devices. Called Swift, it was presented as the language of the future for Apples developers, but it was made very clear that it would cooperate with the existing basic development language Objective-C. (In describing the ways Swift and Objective-C would interact, Apple repeatedly used the phrase mix and match not only in the presentations at WWDC, but in other venues as well.)

Think about that date Swift has only been around since June 2014: Were all beginners with Swift.

Swift For Dummies is a beginners introduction to Apples new programming language. The book gets you started developing with Swift. Youll quickly see how to create projects in Swift from the built-in templates that are part of the Xcode development tool. From there, you delve into the features of the language, from the basic to the advanced. Some of these features are unique to Swift whereas other, possibly more familiar features were inherited from other programming languages.

Before we get started with Swift, consider these two points:

• Apple has done this before, and they know how to do it. On both the hardware and software sides, Apple has successfully managed transitions to new technologies. Developers have sometimes cheered, sometimes booed, and even sometimes not even noticed much difference, but nonetheless, Apple has managed to bring them along to a new technology that makes their lives easier and improves things for users.
• The languages are only part of the development environment for Apple. When you develop apps for iOS or OS X, you use the Xcode development tool (technically an Integrated Development Environment, or IDE), the Cocoa or Cocoa Touch frameworks, and a programming language either Objective-C or Swift. What differentiates the iOS and OS X development environment from most others is that the language is only one-third of the overall environment, as well as the fact that a single company (Apple) controls all of that environment.

Cocoa is the framework you use for developing Mac apps; Cocoa Touch is the framework for iOS apps. Both have a common heritage and many similar classes. In general, classes that start with NS are Cocoa classes, and classes that start with UI are Cocoa Touch classes. Many Cocoa NS classes are also used in Cocoa Touch, so youll find both types of classes in many of your apps and in the sample code and templates.

Code examples in this book appear in a monospaced font so that they stand out a bit better. Some non-syntax components appear in an italicized monospaced font. (Thus, weatherConditions might be a variable, but variable could be any variable you want to use.)

Like many languages, including Objective-C, Swift is case-sensitive, so please enter the code that appears in this book exactly as it appears in the text. I also use the standard Cocoa naming conventions such as capitalizing class names and leaving the names of methods and instance variables lowercase.

Note that all URLs in this book appear in a monospaced font as well. In accordance with common usage, most URLs in this book include the subdomain (such as www) at the beginning of many URLs except for addresses that dont require that component (such as developer.apple.com