1 Get ready to build apps with Swift!

This chapter opens with a friendly, “you can do it” invitation to start building iOS apps. It explains what an app is—software created for a purpose—and notes that most people mean mobile apps when they use the term. You’re encouraged to think like a maker: good apps are purposeful and pleasant to use, with clear visuals, simple and readable screens, quick responses, and reliable behavior. To get there, you’ll learn programming—writing step-by-step instructions (code) that tell a computer exactly what to do—so you can offload complex calculations and repetitive work to machines while you focus on creativity.

You’re introduced to Swift, Apple’s modern language for iOS, watchOS, tvOS, and macOS. Swift aims to be concise and readable, with an English-like feel that reduces errors, and Playgrounds let you try code and see results instantly. While Swift is the main tool, the chapter notes that advanced apps sometimes use Objective-C and Apple’s Cocoa frameworks for tasks like graphics, animation, audio/video, data, and networking. You also get a practical roadmap for turning an idea into an app: prototype, test, fix bugs, iterate, and—when ready—submit to the App Store, improving based on feedback and persevering until it’s accepted.

Finally, you prep your toolbox. You’ll need a Mac that can run Xcode; an iPhone or iPad is optional because Xcode includes a simulator. The chapter walks you through installing Xcode, opening it for the first time, and creating a Swift Playground. A paid Apple Developer account is optional for learning, but required to publish on the App Store. You end by writing your first line of Swift—using print to display “Hello Swift Apps!”—and seeing immediate feedback in the Playground, setting you up to build your first real iOS app next.

Screenshots from my first app on the App store

Think of an idea! Apps for everyone!

Walking with a mobile device and walking with a laptop.

All of these app pieces are necessary!

: The programming process

: The steps to creating an app.

: We’ll mostly work with Swift, but we need a little Objective-C and Cocoa to make our apps better.

  MacBook Air and Mac mini are just a couple of options for developing your apps (left); iPad, iPhone and iPod touch are testing options (right)

The default playground.

The playground after you’ve deleted the text.

After you’ve typed your first code, the screen will look like this.

See how the text changed in the sidebar?

1. What would you type if you want to display: “Good morning Swift” in the playground?
2. What will be displayed if you type print(“5+4”)?
3. What will be displayed if you type print(5+4)?
4. What qualities should your app have to be a good app, Why?

FAQ