The iOS Programming : Big Nerd Ranch Guide,

528 Pages·2020·30.728 MB·English

by  Christian Keur, Aaron Hillegass;

iOS Programming: The Big Nerd Ranch Guide
by Christian Keur and Aaron Hillegass
Copyright © 2020 Big Nerd Ranch
All rights reserved. Printed in the United States of America. This publication is protected by copyright, and
permission must be obtained from the publisher prior to any prohibited reproduction, storage in a retrieval system,
or transmission in any form or by any means, electronic, mechanical, photocopying, recording, or likewise. For
information regarding permissions, contact
Big Nerd Ranch
200 Arizona Ave NE, Suite 200
Atlanta, GA 30307
[phone]
https://www.bignerdranch.com
[e-mail]
The 10-gallon hat is a trademark of Big Nerd Ranch.
Exclusive worldwide distribution of the English edition of this book by
Pearson Technology Group
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Indianapolis, IN 46240 USA
http://www.informit.com
The authors and publisher have taken care in writing and printing this book but make no expressed or implied
warranty of any kind and assume no responsibility for errors or omissions. No liability is assumed for incidental
or consequential damages in connection with or arising out of the use of the information or programs contained
herein.
App Store, Apple, Cocoa, Cocoa Touch, Finder, Instruments, iCloud, iPad, iPhone, iPod, iPod touch, iTunes,
Keychain, Mac, macOS, Multi-Touch, Objective-C, Quartz, Retina, Safari, and Xcode are trademarks of Apple,
Inc., registered in the U.S. and other countries.
Many of the designations used by manufacturers and sellers to distinguish their products are claimed as
trademarks. Where those designations appear in this book, and the publisher was aware of a trademark claim, the
designations have been printed with initial capital letters or in all capitals.

ISBN-10  0135265533
ISBN-13  978-0135265536
Seventh edition, first printing, March 2020
Release D.7.1.1
Acknowledgments
While our names appear on the cover, many people helped make this book a reality. We would like to
take this chance to thank them.
• First and foremost we would like to thank Joe Conway for his work on the early editions of this
book. He authored the first three editions and contributed greatly to the fourth edition as well.
Many of the words in this book are still his, and for that, we are very grateful.
• A couple other people went above and beyond with their help on this book. They are Amit Bijlani,
Chris Downie, Chris Morris, Jacob Bullock, Juan Pablo Claude, Mikey Ward, and Zachary
Waldowski.
• The other instructors who teach the iOS Bootcamp feed us a never-ending stream of suggestions
and corrections. Over the years, they have included Ben Scheirman, Bolot Kerimbaev, Brian
Hardy, Chris Downie, Chris Morris, Drew Kreuzman, Gabe Hoffman, JJ Manton, Jacob Bullock,
John Gallagher, Jonathan Blocksom, Joseph Dixon, Juan Pablo Claude, Mark Dalrymple,
Matt Bezark, Matt Mathias, Mike Zornek, Mikey Ward, Pouria Almassi, Robert Edwards, Rod
Strougo, Scott Ritchie, Step Christopher, Thomas Ward, TJ Usiyan, Tom Harrington, and Zachary
Waldowski. These instructors were often aided by their students in finding book errata, so many
thanks are due to all the students who attend the iOS Bootcamp.
• Thanks to all the employees at Big Nerd Ranch who helped review the book, provided
suggestions, and found errata.
• Our tireless editor, Elizabeth Holaday, took our distracted mumblings and made them into
readable prose.
• Simone Payment jumped in to provide proofing.
• Ellie Volckhausen designed the cover. (The photo is of the bottom bracket of a bicycle frame.)
• Chris Loper at IntelligentEnglish.com designed and produced the print and ebook versions of the
book.
• The amazing team at Pearson Technology Group that has patiently guided us through the business
end of book publishing.
The final and most important thanks goes to our students, whose questions inspired us to write this
book and whose frustrations inspired us to make it clear and comprehensible.
iii

Table of Contents
Introduction ................................................................................................................... xiii
Prerequisites .......................................................................................................... xiii
What Has Changed in the Seventh Edition? ................................................................ xiii
Our Teaching Philosophy ......................................................................................... xiv
How to Use This Book ............................................................................................. xv
How This Book Is Organized .................................................................................... xv
Style Choices ........................................................................................................ xvii
Typographical conventions .............................................................................. xvii
Necessary Hardware and Software ............................................................................ xvii
1. A Simple iOS Application .............................................................................................. 1
Creating an Xcode Project .......................................................................................... 2
Model-View-Controller ............................................................................................... 6
Designing Quiz ......................................................................................................... 7
Interface Builder ....................................................................................................... 8
Building the Interface ................................................................................................ 9
Creating view objects ....................................................................................... 10
Configuring view objects .................................................................................. 12
Running on the simulator .................................................................................. 14
A brief introduction to Auto Layout ................................................................... 15
Making connections ......................................................................................... 19
Creating the Model Layer ......................................................................................... 25
Implementing action methods ............................................................................ 26
Loading the first question ................................................................................. 26
Building the Finished Application .............................................................................. 27
Application Icons .................................................................................................... 28
Launch Screen ........................................................................................................ 31
For the More Curious: Running an Application on a Device ............................................ 32
2. The Swift Language ..................................................................................................... 35
Types in Swift ........................................................................................................ 36
Using Standard Types ............................................................................................... 37
Inferring types ................................................................................................ 39
Specifying types .............................................................................................. 39
Literals and subscripting ................................................................................... 41
Initializers ...................................................................................................... 42
Properties ....................................................................................................... 43
Instance methods ............................................................................................. 43
Optionals ................................................................................................................ 44
Subscripting dictionaries ................................................................................... 46
Loops and String Interpolation ................................................................................... 46
Enumerations and the Switch Statement ...................................................................... 48
Enumerations and raw values ............................................................................. 49
Closures ................................................................................................................. 50
Exploring Apple’s Swift Documentation ...................................................................... 51
3. Views and the View Hierarchy ....................................................................................... 53
View Basics ............................................................................................................ 54
v
iOS Programming
The View Hierarchy ................................................................................................. 54
Creating a New Project ............................................................................................. 56
Views and Frames ................................................................................................... 57
Customizing the labels ..................................................................................... 65
The Auto Layout System .......................................................................................... 68
The alignment rectangle and layout attributes ....................................................... 68
Constraints ..................................................................................................... 69
Adding constraints in Interface Builder ............................................................... 71
Intrinsic content size ........................................................................................ 74
Misplaced views .............................................................................................. 75
Adding more constraints ................................................................................... 76
Challenges .............................................................................................................. 78
Bronze Challenge: More Auto Layout Practice ............................................................. 79
Silver Challenge: Adding a Gradient Layer .................................................................. 79
Gold Challenge: Spacing Out the Labels ..................................................................... 80
For the More Curious: Retina Display ......................................................................... 81
4. View Controllers .......................................................................................................... 83
The View of a View Controller .................................................................................. 84
Setting the Initial View Controller .............................................................................. 85
Tab Bar Controllers .................................................................................................. 88
Tab bar items .................................................................................................. 91
Loaded and Appearing Views .................................................................................... 94
Refactoring in Xcode ....................................................................................... 96
Accessing subviews ......................................................................................... 98
Interacting with View Controllers and Their Views ........................................................ 98
Bronze Challenge: Another Tab ................................................................................. 99
Silver Challenge: Different Background Colors ............................................................. 99
5. Programmatic Views ................................................................................................... 101
Creating a View Programmatically ............................................................................ 103
Programmatic Constraints ........................................................................................ 104
Anchors ........................................................................................................ 105
Activating constraints ..................................................................................... 106
Layout guides ................................................................................................ 107
Margins ........................................................................................................ 108
Explicit constraints ......................................................................................... 109
Programmatic Controls ........................................................................................... 110
Bronze Challenge: Points of Interest ......................................................................... 112
Silver Challenge: Rebuild the Conversion Interface ...................................................... 112
For the More Curious: NSAutoresizingMaskLayoutConstraint ....................................... 113
6. Text Input and Delegation ............................................................................................ 115
Text Editing .......................................................................................................... 116
Keyboard attributes ........................................................................................ 121
Responding to text field changes ...................................................................... 122
Dismissing the keyboard ................................................................................. 124
Implementing the Temperature Conversion ................................................................. 126
Number formatters ......................................................................................... 129
Delegation ............................................................................................................ 130
Conforming to a protocol ................................................................................ 130
vi
iOS Programming
Using a delegate ............................................................................................ 131
More on protocols .......................................................................................... 133
Bronze Challenge: Disallow Alphabetic Characters ...................................................... 134
Silver Challenge: Displaying the User’s Region ........................................................... 134
7. Internationalization and Localization .............................................................................. 135
Internationalization ................................................................................................. 138
Formatters .................................................................................................... 138
Base internationalization ................................................................................. 142
Preparing for localization ................................................................................ 143
Localization .......................................................................................................... 150
NSLocalizedString and strings tables ................................................................. 153
Bronze Challenge: Another Localization .................................................................... 157
For the More Curious: Bundle’s Role in Internationalization .......................................... 157
For the More Curious: Importing and Exporting as XLIFF ............................................ 158
8. Debugging ................................................................................................................ 159
A Buggy Project .................................................................................................... 159
Debugging Basics .................................................................................................. 161
Interpreting console messages .......................................................................... 161
Fixing the first bug ........................................................................................ 164
Caveman debugging ....................................................................................... 165
The Xcode Debugger: LLDB ................................................................................... 167
Setting breakpoints ......................................................................................... 167
Stepping through code .................................................................................... 169
The LLDB console ......................................................................................... 178
9. UITableView and UITableViewController ....................................................................... 181
Beginning the LootLogger Application ...................................................................... 182
UITableViewController ........................................................................................... 184
Subclassing UITableViewController .................................................................. 185
Creating the Item Class ........................................................................................... 187
Custom initializers ......................................................................................... 187
UITableView’s Data Source ..................................................................................... 189
Giving the controller access to the store ............................................................. 191
Implementing data source methods ................................................................... 193
UITableViewCells .................................................................................................. 194
Creating and retrieving UITableViewCells .......................................................... 196
Reusing UITableViewCells .............................................................................. 198
Editing Table Views ............................................................................................... 200
Editing mode ................................................................................................ 200
Adding rows ................................................................................................. 205
Deleting rows ................................................................................................ 208
Moving rows ................................................................................................. 209
Design Patterns ...................................................................................................... 211
Bronze Challenge: Sections ..................................................................................... 212
Silver Challenge: Constant Rows .............................................................................. 212
Gold Challenge: Favorite Items ................................................................................ 212
10. Subclassing UITableViewCell ..................................................................................... 213
Creating ItemCell ................................................................................................... 214
Exposing the Properties of ItemCell .......................................................................... 216
vii
iOS Programming
Using ItemCell ...................................................................................................... 218
Dynamic Cell Heights ............................................................................................ 219
Dynamic Type ....................................................................................................... 220
Responding to user changes ............................................................................. 223
Bronze Challenge: Cell Colors ................................................................................. 224
Silver Challenge: Long Item Names .......................................................................... 224
11. Stack Views ............................................................................................................. 225
Using UIStackView ................................................................................................ 227
Implicit constraints ......................................................................................... 229
Stack view distribution .................................................................................... 231
Nested stack views ......................................................................................... 232
Stack view spacing ......................................................................................... 232
Segues ................................................................................................................. 234
Hooking Up the Content ......................................................................................... 235
Passing Data Around .............................................................................................. 242
Bronze Challenge: More Stack Views ........................................................................ 243
12. Navigation Controllers ............................................................................................... 245
UINavigationController ........................................................................................... 247
Navigating with UINavigationController .................................................................... 251
Appearing and Disappearing Views ........................................................................... 252
Dismissing the Keyboard ......................................................................................... 253
Event handling basics ..................................................................................... 254
Dismissing by pressing the Return key .............................................................. 254
Dismissing by tapping elsewhere ...................................................................... 256
UINavigationBar .................................................................................................... 258
Adding buttons to the navigation bar ................................................................. 261
Bronze Challenge: Displaying a Number Pad .............................................................. 264
Silver Challenge: A Different Back Button Title .......................................................... 264
Gold Challenge: Pushing More View Controllers ......................................................... 264
13. Saving, Loading, and Scene States ............................................................................... 265
Codable ................................................................................................................ 266
Property Lists ........................................................................................................ 267
Error Handling ...................................................................................................... 269
Application Sandbox .............................................................................................. 271
Constructing a file URL .................................................................................. 272
Scene States and Transitions .................................................................................... 273
Persisting the Items ................................................................................................ 277
Notification center .......................................................................................... 278
Saving the Items ............................................................................................ 280
Loading the Items .......................................................................................... 282
Bronze Challenge: Throwing Errors .......................................................................... 283
Gold Challenge: Support Multiple Windows ............................................................... 283
For the More Curious: Manually Conforming to Codable .............................................. 284
For the More Curious: Scene State Transitions ............................................................ 286
For the More Curious: The Application Bundle ........................................................... 288
14. Presenting View Controllers ....................................................................................... 291
Adding a Camera Button ......................................................................................... 294
Alert Controllers .................................................................................................... 299
viii
iOS Programming
Presentation Styles ................................................................................................. 302
15. Camera ................................................................................................................... 305
Displaying Images and UIImageView ........................................................................ 306
Taking Pictures and UIImagePickerController ............................................................. 308
Creating a UIImagePickerController .................................................................. 308
Setting the image picker’s delegate ................................................................... 312
Presenting the image picker modally ................................................................. 313
Permissions ................................................................................................... 314
Saving the image ........................................................................................... 316
Creating ImageStore ............................................................................................... 317
Giving View Controllers Access to the Image Store ..................................................... 318
Creating and Using Keys ......................................................................................... 320
Persisting Images to Disk ........................................................................................ 322
Loading Images from the ImageStore ........................................................................ 324
Bronze Challenge: Editing an Image ......................................................................... 325
Silver Challenge: Removing an Image ....................................................................... 325
For the More Curious: Navigating Implementation Files ............................................... 325
// MARK: ..................................................................................................... 327
16. Adaptive Interfaces ................................................................................................... 329
Size Classes .......................................................................................................... 329
Modifying traits for a specific size class ............................................................ 330
Adapting to Dark Mode .......................................................................................... 336
Adding colors to the Asset Catalog ................................................................... 340
Using custom dynamic colors .......................................................................... 342
Bronze Challenge: Stacked Text Field and Labels ........................................................ 347
17. Extensions and Container View Controllers ................................................................... 349
Starting Mandala ................................................................................................... 350
Creating the model types ................................................................................. 350
Adding resources to the Asset Catalog ............................................................... 351
Extensions ............................................................................................................ 353
Creating a custom container view controller ............................................................... 356
Creating the MoodSelectionViewController ........................................................ 357
Creating the MoodListViewController ............................................................... 365
Handling the embed segue ............................................................................... 368
18. Custom Controls ....................................................................................................... 371
Creating a Custom Control ...................................................................................... 372
Relaying actions ............................................................................................ 375
Using the Custom Control ....................................................................................... 376
Updating the Interface ............................................................................................ 377
Adding the Highlight View ...................................................................................... 379
Bronze Challenge: More Access Control .................................................................... 381
19. Controlling Animations .............................................................................................. 383
Property Animators ................................................................................................ 384
Basic animations ............................................................................................ 384
Timing functions ............................................................................................ 385
Spring animations .......................................................................................... 386
Animating Colors ................................................................................................... 387
Animating a Button ................................................................................................ 389
ix
iOS Programming
20. Web Services ........................................................................................................... 391
Starting the Photorama Application ........................................................................... 392
Building the URL .................................................................................................. 394
Formatting URLs and requests ......................................................................... 394
URLComponents ........................................................................................... 395
Sending the Request ............................................................................................... 398
URLSession .................................................................................................. 399
Modeling the Photo ................................................................................................ 402
JSON Data ........................................................................................................... 402
JSONDecoder and JSONEncoder ...................................................................... 403
Parsing JSON data ......................................................................................... 403
Enumerations and Associated Values ......................................................................... 405
Passing the Photos Around ...................................................................................... 406
Downloading and Displaying the Image Data ............................................................. 412
The Main Thread ................................................................................................... 414
Bronze Challenge: Printing the Response Information .................................................. 416
Silver Challenge: Fetch Recent Photos from Flickr ...................................................... 416
For the More Curious: HTTP ................................................................................... 417
21. Collection Views ...................................................................................................... 419
Displaying the Grid ................................................................................................ 420
Collection View Data Source ................................................................................... 421
Customizing the Layout .......................................................................................... 424
Creating a Custom UICollectionViewCell .................................................................. 427
Downloading the Image Data ................................................................................... 432
Image caching ............................................................................................... 436
Navigating to a Photo ............................................................................................. 437
Bronze Challenge: Horizontal Scrolling ..................................................................... 441
Silver Challenge: Updated Item Sizes ........................................................................ 441
22. Core Data ................................................................................................................ 443
Object Graphs ....................................................................................................... 443
Entities ................................................................................................................. 444
Modeling entities ........................................................................................... 445
NSManagedObject and subclasses .................................................................... 450
NSPersistentContainer ............................................................................................. 451
Updating Items ...................................................................................................... 452
Inserting into the context ................................................................................. 452
Saving changes .............................................................................................. 454
Updating the Data Source ....................................................................................... 455
Fetch requests and predicates ........................................................................... 455
Silver Challenge: Photo View Count ......................................................................... 460
For the More Curious: The Core Data Stack ............................................................... 460
NSManagedObjectModel ................................................................................. 460
NSPersistentStoreCoordinator ........................................................................... 460
NSManagedObjectContext ............................................................................... 460
23. Core Data Relationships ............................................................................................ 461
Relationships ......................................................................................................... 462
Adding Tags to the Interface .................................................................................... 465
Background Tasks .................................................................................................. 476
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