Kevin Mcneish

Author Details

Kevin McNeish's picture

Author Details

Kevin McNeish

Kevin McNeish is author of the new book “Learn to Code in Swift” as well as the “iOS App Development for Non-Programmers” book series (www.iOSAppsForNonProgrammers.com), winner of the Publishing Innovation Award. Kevin is also an award-winning app developer, software architect, and conference speaker in the U.S. and abroad. He has spent much of his career making difficult concepts easy to understand. Follow Kevin on Twitter: @kjmcneish.

In this second part of my two-part post on Demystifying Swift's Initializers, I explain the concepts of initializer chaining, two-phase initialization, and initializer inheritance using hands-on examples that walk you through some of these deeper concepts. You can read part 1 of this post at this link.

If you would like to follow along and perform the step-by-step instructions with this post (highly recommended) you can download the project we have completed so far at this link.

Now that Apple has officially released Xcode 6 and the NDA has been lifted, it's time to dive deeper into Swift—Apple's new language for building iOS apps. Learning how to properly use initializers in Swift can be daunting at first. Swift's requirement that all stored properties in a class are initialized adds complexity to the initialization process. In the first part of this two-part post I'm going to demystify initializers as I provide a hands-on approach to learning how to best implement initializers in your custom classes.

Even though Apple has provided the new Swift programming language for building iOS apps, one thing remains the same—we still use the Cocoa Touch Framework libraries to build iOS functionality into our apps. However, since the Cocoa Touch Framework is written in Objective-C, how is this accomplished? In this article I'll show you the mechanics behind how Swift accesses Objective-C code, and how the Cocoa Touch APIs (application programming interfaces) change when you access them from Swift.

As promised, here is my first installment on learning to program in the new Swift language!

Defining Classes in Swift

The following code shows an example of a Swift class definition:

To declare a class in Swift, you use the class keyword followed by the name of the class. If it has a superclass, you add a colon and the name of the superclass. The beginning and end of the class are indicated by the opening and closing curly braces.

Over the years I have literally taught tens of thousands of people how to write code in Objective-C through training classes, conferences, online forums, and my book series. Based on the mountain of feedback I have received, I can tell you some key points that make Swift much easier to learn than Objective-C.

If Objective-C is the only language you have ever coded in, I have one thing to say about moving to Swift. Welcome to the 21st century.

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