About This Edition

This is the fourth time Pragmatic Programmers has offered an introductory book for iOS developers. The previous entries were iPhone SDK Development in 2009 (covering iPhone OS 3), iOS SDK Development in 2012 (for iOS 6), and iOS 8 SDK Development in 2014 (for iOS 8).

Notice that instead of a two-to-three-year gap like the previous titles, the book you’re holding is coming out just one year and one iOS version after the previous one. The motivation for this is that the platform has developed so quickly that the previous books were near-total rewrites of their predecessors, which took years to finish, yet quickly became dated with the release of a new version of the OS and its software development tools.

Also weighing on our minds is the fact that because of all of the changes in Swift 2.0, most of the code from the iOS 8 book doesn’t even compile anymore.

So we’re trying something different this year: a refresh, not a reboot. Instead of rewriting the whole book every three years, we’re going to try to rewrite roughly a third of it every year. If this plan works, it means a perpetually up-to-date title for beginning iOS developers, whenever they happen to decide they’re ready to give the platform a try.

For this year’s edition, specifically, we targeted our handling of the Swift programming language. After a year in the wild (with both authors using it extensively or exclusively in their day jobs), the language is ready to be taken seriously and described in detail. So whereas our iOS 8 book treated Swift as a means to an end (namely, calling the various iOS frameworks), this year we put Swift front-and-center. The first three chapters are an entirely new introduction to the Swift language itself, working in coding “playgrounds” to get us ready to build real apps. The next two chapters after that were inspired by the previous book, but are radically rewritten and reorganized to ease the transition into full-on app development.

None of this should be inferred as saying the rest of the book is a copy-and-paste job. Every example in the book has been rewritten from scratch to take advantage of the Swift 2.0 programming language and its features. Many chapters also have entirely new sections to cover new iOS 9 features, such as automated UI testing (see ​User Interface Testing​) and stack views (see ​Stack Views and the User Detail View Controller​). Also, we have completely rewritten the final chapter, Chapter 17, ​Publishing and Maintaining the App​, to include Apple’s TestFlight beta-testing service and the many changes to its developer Member Center and iTunes Connect sites.