Table Of ContentAdvanced iOS App Architecture
Advanced iOS App Architecture
By René Cacheaux & Josh Berlin
Copyright ©2019 Razeware LLC.
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Advanced iOS App Architecture
Dedications
"To my beautiful wife Lauren, to my fun-loving angel Zara, to my
soon-to-arrive son René Jr., to my parents who have given me
everything, and, last but not least, to my furry pals Paco and Charlie.
I love you all."
— René Cacheaux
"Thanks to my parents for buying me my first, second, and third
computers, and making me put them together myself. Thanks for
allowing me to take any path I wanted in life, even when it’s a little
crazy. Love y'all."
— Josh Berlin
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Advanced iOS App Architecture
About the Authors
Josh Berlin is an author of this book. He loves building thoughtful
user experiences on mobile. He’s currently an iOS engineer at Cruise
Automation making apps for self-driving cars. He's built apps for the
iPhone and iPad since 2008. Josh recently finished culinary school in
Austin, TX. When he's not coding, he's probably cooking or dreaming
of food.
René Cacheaux is an author of this book. He loves to architect and
build software. He currently is a Mobile Architect at Atlassian where
his mission is to design Atlassian's mobile platform. He especially
loves all things mobile and currently architects for both Android and
Apple platforms. René has been engineering iOS apps since 2009 and
has experience in mobile client and server engineering, mobile user
experience design and product management. René has worked on a
wide range of apps spanning from industrial sales enablement to
world-wide social networking. René enjoys starting his days in true
Austin-Texas fashion with a a breakfast taco alongside a freshly
brewed cappuccino. In addition to building mobile apps, he loves to
travel, snow ski, ocean kayak and root for his alma mater, the Texas
Longhorns.
About the Editors
Aaron Douglas is a tech editor for this book. He was that kid taking
apart the mechanical and electrical appliances at five years of age to
see how they worked. He never grew out of that core interest - to
know how things work. He took an early interest in computer
programming, figuring out how to get past security to be able to play
games on his dad's computer. He's still that feisty nerd, but at least
now he gets paid to do it. Aaron works for Automattic
(WordPress.com, WooCommerce, SimpleNote) as a Mobile Lead
primarily on the WooCommerce mobile apps. Find Aaron on Twitter
as @astralbodies or at his blog at https://aaron.blog.
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Advanced iOS App Architecture
Joshua Greene is a tech editor for this book. He is an experienced iOS
developer who loves creating elegant apps. When he's not slinging
code, he enjoys martial arts, Netflix and spending time with his
wonderful wife and two daughters. You can reach him on Twitter at
@jrg_developer.
Manda Frederick is an editor of this book. She has been involved in
publishing for over ten years through various creative, educational,
medical and technical print and digital publications, and is thrilled to
bring her experience to the raywenderlich.com family as Managing
Editor. In her free time, you can find her at the climbing gym,
backpacking in the backcountry, hanging with her dog, working on
poems, playing guitar and exploring breweries.
Darren Ferguson is the final pass editor for this book. He's an
experienced software developer and works for M.C. Dean, Inc, a
systems integration provider from North Virginia. When he's not
coding, you'll find him enjoying EPL Football, traveling as much as
possible and spending time with his wife and daughter. Find Darren
on Twitter at @darren102.
About the Artist
Vicki Wenderlich is the designer and artist of the cover of this book.
She is Ray’s wife and business partner. She is a digital artist who
creates illustrations, game art and a lot of other art or design work for
the tutorials and books on raywenderlich.com. When she’s not
making art, she loves hiking, a good glass of wine and attempting to
create the perfect cheese plate.
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Advanced iOS App Architecture
Table of Contents: Overview
What You Need........................................................ 10
Book License ............................................................ 11
Book Source Code & Forums ................................... 12
About the Cover....................................................... 13
Chapter 1: Welcome................................................. 14
Chapter 2: Which Architecture Is Right for Me? ....... 16
Chapter 3: Example App: Koober ............................ 34
Chapter 4: Objects & Their Dependencies.............. 47
Chapter 5: Architecture: MVVM ............................. 115
Chapter 6: Architecture: Redux.............................. 167
Chapter 7: Architecture: Elements, Part 1............... 212
Chapter 8: Architecture: Elements, Part 2 ............. 233
Conclusion ............................................................ 297
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Advanced iOS App Architecture
Table of Contents: Extended
What You Need . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
Book License . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
Book Source Code & Forums. . . . . . . . . . . . . . . . . . . . . . 12
About the Cover. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
Chapter 1: Welcome . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
What lies ahead . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
Who this book is for. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
Where to go from here?. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
Chapter 2: Which Architecture Is Right for Me? . . . . . 16
Identifying problems to solve . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
Boosting team velocity and strengthening code quality . . . . . . . . . . . 17
Examining the problems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
Increasing code agility . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
Surveying architecture patterns. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
Selecting a pattern. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31
Putting patterns into practice. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32
Key points . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33
Chapter 3: Example App: Koober . . . . . . . . . . . . . . . . . 34
Koober . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34
Why Koober? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41
Getting started with the source . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41
Key points . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46
Chapter 4: Objects & Their Dependencies. . . . . . . . . 47
Establishing the goals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47
Learning the lingo . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48
Creating dependencies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51
The fundamental considerations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52
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Advanced iOS App Architecture
Why is this architecture?. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53
Dependency patterns . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 54
Dependency Injection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55
On-demand approach. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 59
Factories approach . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 61
Single-container approach . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 67
Designing container hierarchies. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 69
Applying DI theory to iOS apps. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 74
Applying the on-demand approach . . . . . . . . . . . . . . . . . . . . . . . . . . . 82
Applying the factories approach . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 88
Applying the single-container approach . . . . . . . . . . . . . . . . . . . . . . 100
Applying the container hierarchy approach . . . . . . . . . . . . . . . . . . . . 107
Key points. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 113
Where to go from here?. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 114
Chapter 5: Architecture: MVVM . . . . . . . . . . . . . . . . . . 115
What is it?. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 116
Container views . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 122
Communicating amongst view models. . . . . . . . . . . . . . . . . . . . . . . . 124
Navigating . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 125
Applying theory to iOS apps . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 128
Composing views. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 139
Navigating . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 148
Managing state . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 159
Key points . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 164
Pros and cons of MVVM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 164
Where to go from here?. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 166
Chapter 6: Architecture: Redux . . . . . . . . . . . . . . . . . . 167
History . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 167
What is Redux? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 168
Applying theory to iOS apps . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 179
Key points . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 209
Pros and cons of Redux . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 209
Where to go from here?. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 211
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Advanced iOS App Architecture
Chapter 7: Architecture: Elements, Part 1 . . . . . . . . . 212
Introducing Elements. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 213
Underlying concepts of Elements. . . . . . . . . . . . . . . . . . . . . . . . . . . . 214
User interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 218
Interaction responder . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 226
Key points . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 232
Chapter 8: Architecture: Elements, Part 2 . . . . . . . . 233
Observer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 233
Use case . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 266
Pros and cons of Elements. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 295
Key points . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 296
Conclusion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 297
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W
What You Need
To follow along with this book, you'll need the following:
• A Mac running macOS Mojave (10.14.3) or later.
• Swift 5: all projects have been written to work with Swift 5 in Xcode.
• Xcode 10.2 or later. You'll need Xcode 10.2 or later to open and run the example
apps included in this book.
If you haven't installed the latest version of macOS or Xcode, be sure to do that before
continuing with the book. The code covered in this book depends on Swift 5 and Xcode
10.2.
This book provides the building blocks for developers who wish to broaden their
horizons and learn how architectures can help them build robust and maintainable
applications and SDKs.
The only prerequisites for this book are an intermediate understanding of Swift and iOS
development. If you’ve worked through our classic beginner books — Swift Apprentice
https://store.raywenderlich.com/products/swift-apprentice and iOS Apprentice https://
store.raywenderlich.com/products/ios-apprentice — or have similar development
experience, you’re ready to read this book.
As you work through the book, you’ll be taken through a deep dive into different
architectures for a fictional app named Koober. Each chapter will explain the theory
behind each of the architectures first. The second half of the chapters will guide you
through how the Koober application utilized the architecture and show you how the
architecture was used within the application.
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