Anyone Can Create an App: Beginning iPhone and iPad programming

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Development editor: Christina Taylor

Technical development editor: Robin Dewson

Review editor: Ozren Harlovic

Project editor: Tiffany Taylor

Copy editor: Corbin Collins

Proofreader: Melody Dolab

Technical proofreader: Scott Steinman

Typesetter: Dennis Dalinnik

Cover designer: Leslie Haimes

ISBN: 9781617292651

Printed in the United States of America

1 2 3 4 5 6 7 8 9 10 – EBM – 22 21 20 19 18 17

Dedication

To my wife, who so patiently puts up with me.

To my parents, who so patiently put up with me for all those years.

And to the rest of my friends and family, who put up with me,

although sometimes not as patiently as I would like.

Brief Table of Contents

Copyright

Brief Table of Contents

Table of Contents

Preface

Acknowledgments

About this Book

1. Your very first app

Chapter 1. Getting started

Chapter 2. Building your first app

Chapter 3. Your first app, explained

Chapter 4. Learning more about your development tools: Xcode

Chapter 5. Capturing users’ actions: adding buttons

Chapter 6. The button app, explained

Chapter 7. Capturing user input: adding text boxes

Chapter 8. Playing on the playground

2. The keys to the city: understanding key development concepts

Chapter 9. Go with the flow, man! Controlling the flow of your app

Chapter 10. While you’re doing that...

Chapter 11. Collections

Chapter 12. Telling stories with storyboards

Chapter 13. ViewControllers in depth

Chapter 14. Put it on my tab: creating tab bars

Chapter 15. Table views: more than a coffee table picture book

Chapter 16. Patterns: learning to sew

3. Creating the Like it or Not app

Chapter 17. Putting it all together: the LioN app

Chapter 18. Adding data to your LioN app

Chapter 19. Displaying details of your LioN

Chapter 20. Creating the details of the detail view

Chapter 21. The AddEditView scene

Chapter 22. Delegates are everywhere

Chapter 23. Editing LioNs

Chapter 24. Saving LioNs

Chapter 25. Making your LioN prettier

Chapter 26. Working with Auto Layout

Chapter 27. Search your LioNs

Appendix A. Installing Xcode and Apple developer registration

Appendix B. Running the app on your device

 Overview

 Topics covered

Index

List of Figures

Table of Contents

Copyright

Brief Table of Contents

Table of Contents

Preface

Acknowledgments

About this Book

1. Your very first app

Chapter 1. Getting started

1.1. The big picture: iPhone and iPad development

1.1.1. Some key terms

1.1.2. Am I developing or programming?

1.1.3. Objectively Swift

1.1.4. Apps you’ll create

1.2. Learning what you need to remember

1.2.1. Understanding and remembering key concepts

1.2.2. Syntax

1.2.3. The importance of pseudocode

1.3. What you need to create apps for iPhones and iPads

1.3.1. You’re going to need a Mac

1.3.2. Xcode: the iPhone and iPad development environment

1.3.3. Helpful resources

1.4. Summary

Chapter 2. Building your first app

2.1. Launching Xcode for the first time

2.1.1. Step 1: Launch Xcode

2.1.2. Step 2: Create a new project

2.1.3. Step 3: Set up your project options

2.1.4. Step 4: Run the blank app

2.1.5. Step 5: Add the Hello World text

2.1.6. Step 6: Run the app

2.1.7. Step 7: Pat yourself on the back (and review)

2.2. Summary

Chapter 3. Your first app, explained

3.1. Xcode templates, explained

3.2. Understanding the single-view application

3.3. A label, defined

3.4. The Simulator, defined

3.4.1. Running Hello World in the Simulator

3.5. Summary

Chapter 4. Learning more about your development tools: Xcode

4.1. Xcode panels explained

4.1.1. Standard Editor

4.1.2. Utilities panel

4.1.3. Main.storyboard

4.1.4. Navigator panel

4.2. Xcode icons explained

4.3. Feel free to explore

4.4. Summary

Chapter 5. Capturing users’ actions: adding buttons

5.1. Adding a label and a button

5.1.1. Step 1: Start a new project using the Single View Application template

5.1.2. Step 2: Add a button and label to the storyboard, and run the app to test it

5.1.3. Step 3: Connect the button and the label to the code (wire them up), and run the app to test it

5.1.4. Step 4: Add code to change the text on the Label when the button is clicked, and run the app to test it

5.2. Changing how the label appears

5.2.1. Step 5: Change how the label looks, and run the app to test it

5.3. Summary

Chapter 6. The button app, explained

6.1. The button, explained

6.1.1. Creating outlets (or How do I contact Butch?)

6.1.2. Creating actions

6.1.3. Is Xcode clairvoyant?

6.1.4. User interfaces and the front end of apps

6.2. Documentation

6.3. Commenting: you can never be too wordy, can you?

6.3.1. Comments are your friends

6.3.2. How to comment your code

6.4. Summary

Chapter 7. Capturing user input: adding text boxes

7.1. Adding text fields

7.1.1. Step 1: Create a new single-view application

7.1.2. Step 2: Add a button and a label to the view

7.1.3. Step 3: Add a text field to the view

7.1.4. Step 4: Connect the button, label, and text box to the code (wire them up), and test the app

7.1.5. Step 5: Add code to change the label, and test the app

7.1.6. Step 6: Comment the code

7.2. Summary

Chapter 8. Playing on the playground

8.1. Swift Playgrounds: learning to interact with others

8.2. Frameworks

8.3. Types of variables

8.3.1. Not your shoestrings

8.3.2. Going back to math class

8.3.3. Double, double, toil and trouble

8.4. Summary

2. The keys to the city: understanding key development concepts

Chapter 9. Go with the flow, man! Controlling the flow of your app

9.1. Control your flow

9.2. If you do that again, I’m going to...

9.3. If you do that OR if you... then I’m going to...

9.4. If you do that AND you do this, I will...

9.5. If you do this, else if you do this, else if you do this...

9.5.1. Printing a line with values of variables and strings

9.6. If you do that, otherwise...

9.7. Summary

Chapter 10. While you’re doing that...

10.1. Using the while statement to control your code

10.1.1. The while statement in action

10.1.2. Wrapping up the while statement discussion

10.2. Turn around now switch (remember Will Smith?)—the switch statement

10.2.1. Assignment

10.3. How many fingers am I holding up?

10.3.1. Step 1: Add all the components to the storyboard

10.3.2. Step 2: Make the storyboard connections

10.3.3. Step 3: Create a variable to capture the number guessed: numberGuessed

10.3.4. Step 4: Change the numberGuess variable when the stepper is tapped

10.3.5. Connecting the Guess! button

10.4. Summary

Chapter 11. Collections

11.1. Quantum arrays: not really, but that sounds **br/** scary, right?

11.2. The for statement and loop

11.3. Dictionaries

11.4. Creating a state name lookup app

11.4.1. Step 1: Create an app named StateAbbreviationLookup

11.4.2. Step 2: Add the UI components to the storyboard

11.4.3. Step 3: Connect the UI components to the code

11.4.4. Step 4: Create the dictionary of state abbreviations and names

11.4.5. Step 5: Create the code to look up the state abbreviation when the user types in the state name

11.5. Summary

Chapter 12. Telling stories with storyboards

12.1. Storyboards

12.2. Creating an example storyboard app

12.2.1. Step 1: Create a new app called StoryboardExample

12.2.2. Step 2: Add a second scene to the app

12.2.3. Step 3: Add a navigation bar to the second scene

12.2.4. Step 4: Link the Cancel button to the first scene

12.3. Segue animation types

12.4. Summary

Chapter 13. ViewControllers in depth

13.1. Inheritance

13.2. The override keyword

13.3. ViewController lifecycles

13.4. The Lifecycle app

13.4.1. Step 1: Create a new project called Lifecycle

13.4.2. Step 2: Add a second ViewController

13.4.3. Step 3: Create an unwind segue

13.4.4. Step 4: Override the five functions

13.4.5. Step 5: Test the app

13.5. Summary

Chapter 14. Put it on my tab: creating tab bars

14.1. The Tab Bar Controller

14.1.1. Step 1: Create a new app

14.1.2. Step 2: Delete the existing scene

14.1.3. Step 3: Add a Tab Bar Controller to the storyboard

14.1.4. Step 4: Add labels to the different tabs

14.1.5. Step 5: Add a third tab to the app

14.2. Summary

Chapter 15. Table views: more than a coffee table picture book

15.1. Delegation

15.1.1. Making pizza from scratch

15.1.2. Delegating pizza making

15.2. Protocols

15.3. Data sources

15.4. Creating a table view app

15.4.1. Step 1: Create a new app

15.4.2. Step 2: Add a table view to the ViewController

15.4.3. Step 3: Set up a prototype cell

15.4.4. Step 4: Set the protocols for UITableView

15.4.5. Step 5: Create a data source for the pizza

15.4.6. Step 6: Connect the data to a table

15.5. Summary

Chapter 16. Patterns: learning to sew

16.1. Design patterns, defined

16.1.1. Clean code

16.1.2. Understandable

16.1.3. Maintainable

16.1.4. Extensibility

16.2. Types of design patterns

16.2.1. Model-View-Controller design pattern

16.2.2. Delegate pattern

16.2.3. The Memento pattern

16.3. Summary

3. Creating the Like it or Not app

Chapter 17. Putting it all together: the LioN app

17.1. Like it or Not

17.2. Getting started

17.2.1. Creating the app

17.2.2. Adding a Navigation Controller

17.2.3. Adding an iPhone 4s Simulator

17.2.4. Connecting the data to the table view

17.2.5. Implement the functions for table views

17.3. Summary

Chapter 18. Adding data to your LioN app

18.1. Adding hardcoded data to your LioN

18.1.1. Creating an array of dummy data

18.1.2. Wiring lionData to the table view with hardcoded data

18.2. Adding a model to the mix

18.2.1. Adding a new Swift file to the project

18.3. Changing the layout of the table cell

18.3.1. Changing the cell in the storyboard to show the description

18.3.2. Updating the function to show the description

18.4. Summary

Chapter 19. Displaying details of your LioN

19.1. Capturing the tapped row index

19.2. Adding a detail page to the storyboard

19.2.1. Adding a ViewController to the storyboard

19.2.2. Creating a new ViewController class

19.3. Passing data to the DetailViewController

19.3.1. Preparing the DetailViewController to accept the LioN

19.3.2. Updating the MainViewController to pass data

19.4. Summary

Chapter 20. Creating the details of the detail view

20.1. Adding some labels to your detail screen

20.1.1. Converting an Int to a string using the description

20.1.2. Converting an Int to a string using String

20.2. Adding new LioNs to the list

20.2.1. Adding the + button to the view

20.2.2. Creating a function to handle the action and link the **br/** two together

20.2.3. Adding hardcoded values to the LioN list

20.2.4. Deleting LioNs from the list

20.3. Summary

Chapter 21. The AddEditView scene

21.1. Creating a new detail view

21.1.1. Adding a new Table ViewController

21.1.2. Adding a new AddEditViewController class

21.1.3. Hooking up the Cancel and Done buttons

21.1.4. Checkpoint

21.2. Adding new LioNs

21.2.1. Don’t allow the cell to be selected

21.2.2. Setting the keyboard behaviors

21.2.3. Dismissing the keyboard on user tap

21.3. Summary

Chapter 22. Delegates are everywhere

22.1. Connecting your views

22.1.1. Implementing the protocol

22.1.2. Updating your Cancel and Done actions

22.1.3. Capturing the user input

22.2. MainViewController conformance

22.3. Adding the LioN object to the lion array

22.3.1. Changing the Done button properties

22.4. Setting the like and dislike properties

22.5. Summary

Chapter 23. Editing LioNs

23.1. Editing existing LioNs

23.1.1. Setting up the AddEditViewController to accept a LioN object **br/** to edit

23.1.2. Filling in the text boxes with the LioN name and description

23.1.3. Showing whether the LioN is liked or disliked

23.1.4. Passing the LioN object to the Add/Edit controller

23.1.5. Saving the LioN when the user taps Done, but not creating a new LioN

23.2. Summary

Chapter 24. Saving LioNs

24.1. Playing in the sandbox

24.2. Saving your data

24.2.1. Changing the class definition for the LioN object

24.2.2. Encoding the data for saving

24.2.3. Decoding the data for loading

24.2.4. Adding the loadLions() function

24.2.5. Loading summary

24.2.6. Adding save functionality

24.3. Testing the load and save functionality

24.4. Summary

Chapter 25. Making your LioN prettier

25.1. Basic fixes

25.1.1. Creating two sections

25.1.2. Adding the Like and Dislike images

25.1.3. Changing the table view background colors

25.1.4. Toggling the images based on selection

25.1.5. Setting images on the cells

25.1.6. Making the MainView scene prettier

25.1.7. Updating the navigation bars

25.2. Adding an icon

25.3. Updating the launch scene

25.4. Summary

Chapter 26. Working with Auto Layout

26.1. Changing the layout to work for all screen sizes

26.1.1. Make changes to the AddEditView scene

26.1.2. Changing the color of cells on the main scene

26.2. Summary

Chapter 27. Search your LioNs

27.1. Adding the search functionality

27.2. Filtering LioNs based on user input

27.2.1. Creating the filter function

27.2.2. Filtering the array using a closure

27.2.3. Changing the table view data source

27.2.4. Polishing the app

27.3. Searching other fields

27.4. Summary

27.5. Where do you go from here?

Appendix A. Installing Xcode and Apple developer registration

A.1 Downloading and installing Xcode

A.2 Apple requirements for iPhone and iPad development

Appendix B. Running the app on your device

 Overview

 Topics covered

Index

List of Figures

Preface

I’m incredibly excited to have finally completed this book. I want to see more people learning to program, but some are intimidated by the enormous world of programming and have trouble finding a good place to start. I hope this book will help.

I didn’t major in Computer Science in college, so I probably started my computer career somewhere close to where you are now. I got my first iPhone when they came out in 2007, and I was enamored. I wanted to create my own apps, so I found a local class that taught iOS programming, and away I went. I’ve been programming on the iPhone in some fashion ever since.

One of the things you’ll notice after you begin programming is that your friends will frequently mention that they have a great idea for an app. Then they’ll ask if you can create it for them, and they’ll promise you a share of what they’re sure will be huge profits. I’ve received so many of these requests that my general response includes telling people they should learn to create the app themselves. They usually follow up with a comment or two about not knowing where to start, not being smart enough, their brain not working like that, or programming being too hard. I constantly deny these things—writing an app isn’t rocket science, and I think everyone can do it, given the time and the tools.

I’ve also been involved in a lot of women’s initiatives: specifically, trying to encourage more girls and women to get into science, technology, engineering, and math (STEM) areas. This STEM interest, combined with my friends asking if I could help them create an app, led me to want to write a book for absolute beginner programmers. This book isn’t written just for girls and women, but that was definitely an inspiration when I began.

Why Manning? Well, I had purchased many Manning books in the past, and they were high quality. And many years ago, I volunteered to review draft manuscripts; I’ve reviewed several, so I was familiar (at a very high level) with the publishing process. As soon as I decided to write the book, I knew it had to be with Manning. I submitted my idea for the book, waited for a few weeks, and then received word that Manning wanted me to write it! Let the panic ensue!

This has been a long, fun journey—one that I wouldn’t trade for anything. It’s been a labor of love, joy, panic, long nights, stress, and happiness. This is the first book I’ve ever written, so I appreciate your reading it, and I hope you enjoy it.

Remember: you are smart enough, and your brain will understand this topic. Be patient—you can do it!

Acknowledgments

There are many people to thank for helping make this crazy dream of mine a reality. Thank you to my biggest supporter: my wife, Jocelyn Whitfield. You believed in me, supported me, encouraged me, and picked me up when I was down. I absolutely could not have completed this book without you. Thank you to my parents for also encouraging me, helping me, and, of course, raising me! Thank you to all of my family and friends, as well. You don’t know just how much your love and support helped me, especially Clay, Kristine, Nancy, and Ja. I love you all!

I also want to thanks the wonderful people at Manning who made this book possible: publisher Marjan Bace and everyone on the editorial and production teams, including Christina Taylor, Janet Vail, Tiffany Taylor, Corbin Collins, Melody Dolab, Dennis Dallinik, and many others who worked behind the scenes.

I can’t thank enough the amazing group of technical peer reviewers led by Ozren Harlovic—Stephen Byrne, Mark Cooper, Igor Delovski, Olivier Ducatteeuw, Laurence Giglio, Pieter Gyselinck, Marius Horga, Jocelyn Jeriah, Kelvin Meeks, Drew Monrad, Jason Pike, and Stuart Woodward—and the talented forum contributors. Their contributions included catching technical mistakes, errors in terminology, and typos, and making topic suggestions. Each pass through the review process and each piece of feedback implemented through the forum topics shaped and molded the manuscript. Special thanks to Robin Dewson, who served as the book’s technical editor, and Scott Steinman, who served as the book’s technical proofreader.

About this Book

I assume you bought this book because you want to learn how to make an iOS app but you’ve never done any coding before (that, or you know me and want to support me!). Either way, you’re going to learn a lot and have fun in the process. The book is meant for people who have never written any code, or who have coded a little something but definitely not an iOS app. It also assumes that you have the patience to read the book, try the examples, and then rework the examples if they didn’t work perfectly the first time. That’s a lot of what coding is: debugging. Even the best developers miss things, so don’t get frustrated when your code doesn’t work exactly right the first time. Patience, Grasshopper.

Why iOS apps? If you tell your friends that you’re learning iOS (or Swift, or developing for Apple phones), they may say, Wow, I heard that was pretty hard. Why don’t you start with something easier? Your answer can be, Well, I have an idea for an app, and I have the patience and willingness to learn. Ergo, I will. People may encourage you to learn something easier, like Hypertext Markup Language (HTML, used in web pages and such). That’s all well and good, but you really wanted to learn to create apps for Apple devices (using Swift), so you’re reading this book. I’m here to tell you, you can start with iOS, and you can learn to write apps; and with time, patience, and resolve, you can be an expert someday if you want to be.

My goal in this book is to give you just enough of what you need to know to complete the next step, without overwhelming you with a lot of things you don’t need to know right now. In other words, I’m trying to teach this subject with just-in-time learning techniques. This means although there may be pages and pages of stuff you could learn about a topic, you don’t need to learn all of that up front. I take all of those pages and distill them down into smaller portions of what you really need to know in order to get started.

Many people are leery of learning to program. The programming world is huge—there are many languages and many acronyms, and it seems as though some programmers haven’t seen the Sun in years. Rest assured, you can get started by learning just the basics, and I’ll walk you through the acronyms and the programmer jargon. Think of programming as just another hobby at this point. You can spend as much or as little time on it as you want, but the more time you devote, the better you’ll be at it. Imagine me accompanying you on the path—we’ll get there together.

Every developer begins slowly, learning the fundamentals. Even the most seasoned programmer had to start somewhere! There isn’t a club that only allows certain people to be developers. Everyone can do it, including you. Take the time to learn the basics, understand the concepts, and work through the exercises, and soon you’ll be an iOS developer, too.

Who is this book is written for?

This book is for absolute programming beginners who’ve never written a line of code and don’t know the underlying concepts for doing so. I make these assumptions:

You have no development experience.

You want to learn to make iOS applications.

You have a Mac on which you can code, or you are willing to purchase a Mac.

You have patience.

I hope this book proves to be the perfect place for you to begin, because I know you can do it!

Who is this book not written for?

If you’re a developer and are already familiar with concepts such as for loops, while loops, and if statements, and you just want to learn more about iOS, this probably isn’t the book for you. You can find other books that teach the syntax of Swift and differences between mobile development and other platform development, and you’ll probably get bored with this book pretty quickly. But if you’re a programmer and are only familiar with languages like HTML or COBOL, you can definitely learn something from this book.

Roadmap

The book is broken into three parts:

Part 1 (chapters 1–8)—This is the beginning of your programming career. You’ll learn the basics of how programming works, you’ll be introduced to Xcode and the Swift Playground, and you’ll write a few simple apps to get started.

Part 2 (chapters 9-16)—These chapters will teach you about some additional skills and concepts needed to create apps, including the while statement, the switch statement, arrays and collections, storyboards, ViewControllers, and tables. Part 2 is more advanced than part 1, so make sure you understand part 1 first.

Part 3 (chapters 17-27)—In these chapters, you’ll create a LioN (Like it or Not) app. The LioN app allows the user to add items to a list and rate whether they like those items. When I’m at the store, I can never remember which toothpaste I like; so, I open the LioN app and search for toothpaste, and the app shows me which toothpaste I like. The app will serve as a complete example you can follow as you go on to create your own apps.

Source code downloads

You can download all the projects from this book and refer to them anytime. They’re available at the Manning website (www.manning.com/books/anyone-can-create-an-app) and on GitHub (https://github.com/wlwise/AnyoneCanCreateAnApp).

Software/hardware requirements

Here’s what you need to get started:

A Mac computer—Chapter 1 gives you the basic requirements if you don’t have a Mac already.

Xcode—This integrated development environment (IDE) is the primary tool you’ll need to create apps. You probably already use a program like Microsoft Word to create documents. Well, Xcode is the application you use to create programs. Appendix A has instructions for installing this free tool, which you’ll begin using in chapter 2. I’ll also go into more detail about Xcode in chapter 4.

A membership in the Apple Developer Program—Appendix A explains how to join. There are two options: a free membership (which I recommend) and a $99 membership.

Online resources

The resource that will provide you with the most help with this book is the book’s website: www.manning.com/books/anyone-can-create-an-app. You can download the examples, ask questions about the exercises in the Author Online forum, and chat with other readers. I’ll try to be as responsive as possible and answer your forum questions, and of course you can tell me what you think of this book.

Apple is another great place to explore, including the resources in the Apple Developer Member Center (http://mng.bz/3OjD). You’ll need to be a member of the Apple Developer Program; see appendix A for more info. You do not need to read these documents to use this book—I’m just providing the location in case you want to learn more about a topic. The Getting Started resources are a good place to start, and the Guides section is another good type of resource is the Guides section.

Stack Overflow (www.stackoverflow.com) is another great place to get answers about specific questions. You can search on your exact need, and it’s almost guaranteed that someone has asked the question before and someone else has answered it. Be as specific as possible when searching, or you’ll get back an excess of information.

About the author

Wendy Wise has an extensive background in mobile and application development and has worked with several Fortune 500 companies. In her 17-year technical career, Wendy has served as a senior director of software development, a senior product manager for international mobile applications, and a hands-on developer for web and mobile technologies, among many other technical roles. Wendy fully embraces her nerd/geek side, as you’ll find out as you read this book. In her spare time, she enjoys beer, coffee, photography, camping, and being outdoors.

Author Online

Purchase of Anyone Can Create an App includes free access to a private web forum run by Manning Publications where you can make comments about the book, ask technical questions, and receive help from the author and from other users. To access the forum and subscribe to it, point your web browser to www.manning.com/books/anyone-can-create-an-app. This page provides information on how to get on the forum once you’re registered, what kind of help is available, and the rules of conduct on the forum.

Manning’s commitment to our readers is to provide a venue where a meaningful dialogue between individual readers and between readers and the author can take place. It’s not a commitment to any specific amount of participation on the part of the author, whose contribution to Author Online remains voluntary (and unpaid). We suggest you try asking the author some challenging questions, lest her interest stray! The Author Online forum and the archives of previous discussions will be accessible from the publisher’s website as long as the book is in print.

Part 1. Your very first app

Part 1 introduces you to the basic concepts of programming and aims to quickly get your feet wet in the programming world. You’ll create your first app in chapter 2 and then in chapter 3 learn more about what you did and why you did it. Chapter 4 walks you through the tool (Xcode) that you use to create apps. You’ll go deeper into the programming world in chapters 5–7 by adding buttons and text boxes. Finally, in chapter 8, you’ll learn about an exciting tool called the Swift Playground, which allows you to learn and test code quickly and easily.

Chapter 1. Getting started

This chapter covers

An overview of creating iPhone and iPad apps

Learning strategy—what to remember

What you’ll need to create apps for iOS

The world is continuously evolving, and the movement to mobile-first is part of that evolution. What is mobile-first? It’s the idea that many people use their iPhones or iPads as their main source of information—whether for email, news, social media, the internet, shopping, texting, or phone calls. Because of this, companies are considering how to provide that information on a mobile device (like an iPhone and iPad) first, rather than the old way, which was to make a web page first and then add mobile device applications (apps) to support it.

It’s an exciting time for technology growth and evolution, and you’re going to be a part of that. This book will teach you what you need to know to get started creating apps for iPhones and iPads. It assumes you have no previous development experience and that this is your first foray into the wonderful world of app creation. If you’ve developed apps before, some if this information may be familiar because we’re starting from the beginning, but everyone can use a refresher every now and then, right?

1.1. The big picture: iPhone and iPad development

Creating apps for iPhones and iPads is exciting. I understand that even thinking of creating apps for these powerful devices may seem daunting, but rest assured that we’re going to do this together, and you’ll complete several applications by the time you’re finished with this book. Making apps for iPhones and iPads is complex enough that it has its own vocabulary, which I’ll teach you.

Creating an app is known as developing software, and by the time you’re finished with this book, you’ll have developed several apps and will have a beginner’s knowledge of software terms and basics. Let’s start with the absolute basics to make sure we’re on the same page (pun intended).

1.1.1. Some key terms

First of all, learning to develop for iPhones and iPads means you’ll create apps that can be installed on and run only on iPhones and iPads. These applications can’t run on any other devices, so make sure you understand what you’re getting into. You’ll learn to develop applications to run on iOS, which is the operating system (OS) that runs on iPhones and iPads. An operating system is the underlying software that runs on machines—like Windows 95 (going old school!), Windows 8.1, or Mac OS X (now macOS). These operating systems do all the hard work of interacting with the electronic components that make up a computer, so you have to interact with the OS instead of trying to tell the computer what you mean when you press a key. The early chapters of this book cover the key concepts of developing for both iPhones and iPads, but the first examples will focus on iPhones. Developing for iPads is not that different, and I’ll show you the differences as we move into later chapters.

1.1.2. Am I developing or programming?

The term development is synonymous with programming because you’re learning to develop or program apps that will make a computer do stuff. There are many, many programming language options to choose from. A programming language is a formally constructed language used to communicate with a machine. When Apple created the iPhone, it created a language called Objective-C (the programming language used before Swift) that, when used by a programmer and compiled or translated by a compiling program called a compiler (more on that later), can be understood and acted upon by the iPhone. Figure 1.1 shows this programming language at work.

Figure 1.1. The app-creation process (the birds and bees of apps)

As the figure shows, using a programming language to create an app for an iPhone or iPad involves the following steps:

You type words on the screen, which are commands or code.

The compiler takes those words, and, if there are no errors in the program, translates them into a language that the machine can understand.

Learning to program is much like learning a foreign language. You need to understand the words and their meaning, and then you must put them together in the right order to form sentences.

1.1.3. Objectively Swift

As mentioned, there are