About the Book

Get started fast with Swift 2 programming for iOS and OS X

Learning Swift 2 Programming is a fast-paced, hands-on introduction to writing production-quality iOS and OS X apps with Apple’s programming language. Written for developers with experience in any modern language, this book explains Swift simply and clearly, using relevant examples that solve realistic problems.

Author Jacob Schatz’s popular YouTube video tutorials have already helped thousands of Apple developers get started with Swift. Now, he helps you take full advantage of Swift’s advanced design, remarkable performance, and streamlined development techniques.

Step by step, you’ll move from basic syntax through advanced features such as closures and generics—discovering helpful tips and tricks along the way. After you’ve mastered Swift’s building blocks and learned about its key innovations, a full section of case studies walks you through building complete apps from scratch.

Learn how to:

• Compare Swift with Objective-C, JavaScript, Python, Ruby, and C
• Collect data with arrays and dictionaries, and store it with variables and constants
• Group commonly used code into functions for easy reuse
• Structure your code with enums, structs, and classes
• Use generics to get more done with less code
• Write closures to share small blocks of functionality
• Use optionals to write more robust, crash-resistant, and cleaner code
• Integrate existing Objective-C code into new Swift apps
• Program on the bit and byte levels with advanced operators
• Implement efficient design patterns with protocols and delegates
• Create animated 2D games with SpriteKit, and apps with UIKit

Table of Contents:
Introduction 1

1 Getting Your Feet Wet: Variables, Constants, and Loops 5
Building Blocks of Swift 6
     Computed Properties (Getters and Setters) 6
     Using Comments 8
     Inference 8
Merging Variables into a String 10
Optionals: A Gift to Unwrap 11
     Printing Your Results 14
     Implicitly Unwrapped Optionals 14
Tuples 15
Number Types 16
From Objective-C to Swift 17
     Control Flow: Making Choices 18
     Switching It Up: switch Statements 25
     Stop...Hammer Time 28
Summary 29

2 Collecting Your Data: Arrays and Dictionaries 31
Using Arrays 31
     Your First Array the Long Way 31
     A Quicker Array 32
     Using AnyObject 32
     Differences Between NSArrays and Swift Arrays 33
Modifying Arrays 33
     Accessing Array Elements 33
     Adding Elements to an Array 34
     Removing Elements from Arrays 34
     Iterating Over Arrays 35
     Extra Bits of Arrays 35
     Emptying an Array 36
Using Dictionaries 36
     Adding, Removing, and Inserting with Dictionaries 37
     Iterating Over Dictionaries 37
     Extra Bits of Dictionaries 38
     Emptying a Dictionary 38
     Testing Dictionaries for the Presence of Values 38
     Putting It All Together 39
Summary 41

3 Making Things Happen: Functions 43
Defining Functions 44
     Return Types 45
     Multiple Return Values 46
More on Parameters 47
     External Parameter Names 47
     Default Parameter Values 48
     Variadic Parameters 49
     In-Out Parameters 50
     Functions as Types 51
     Putting It All Together 52
Summary 55

4 Structuring Code: Enums, Structs, and Classes 57
Enums 58
     Which Member Was Set? 59
     Associated Values 59
     Raw Values 60
Structs 61
     Defining Methods in Structs 63
     Structs Are Always Copied 64
     Mutating Methods 65
     Classes 66
     Initialization 66
     What Is a Reference Type? 68
     Do I Use a Struct or a Class? 68
     Forgot Your Pointer Syntax? 69
     Property Observers 69
     Methods in Classes 70
Summary 74

5 SpriteKit 75
Introducing SpriteKit 75
     The SKNode and SKSpriteNode 75
Creating a Game 76
     The New Project Screen 76
     The Game 85
Summary 92

6 Reusable Code: Closures 93
What Are Closures? 93
Closures in Other Languages 94
How Closures Work and Why They’re Awesome 95
     The Closure Syntax 96
     Inferring Using Context 96
     Arguments Have a Shorthand, Too 97
     Sorting a Custom Car Class 97
     Closures Are Reference Types 98
     Automatic Reference Counting 99
     Strong Reference Cycles 100
     Trailing Closures 106
Summary 107

7 Creating Your Own Syntax: Subscripts and Advanced Operators 109
Writing Your First Subscript 110
Bits and Bytes with Advanced Operators 113
     Bitwise NOT 114
     Bitwise AND 115
     Bitwise OR 116
     Bitwise XOR 117
     Shifting Bits 118
     UInt8, UInt16, UInt32, Int8, Int16, Int32, and So On 119
     Value Overflow and Underflow 119
Customizing Operators 120
Making Your Own Operators 122
Bits and Bytes in Real Life 123
Summary 127

8 Protocols 129
Writing Your First Protocol 129
     Properties 131
Animizable and Humanizable 134
     Methods 135
Delegation 136
Protocols as Types 138
Protocols in Collections 139
     Protocol Inheritance 140
     Protocol Composition 141
     Protocol Conformity 143
     Optional Protocol Prerequisites 145
Optional Chaining 146
     Back to Optional Protocol Requisites 148
     Useful Built-in Swift Protocols 149
Summary 151

9 Becoming Flexible with Generics 153
The Problem That Generics Solve 153
     Other Uses for Generics 155
     Generics for Protocols 157
     The where Clause 158
Summary 162

10 Games with SpriteKit 163
The Game 163
The Setup 163
Tour the Code 164
The Game 164
     Step 1: Create the World 165
     Step 2: Making Things Move 176
Summary 185

11 Making Games with Physics 187
Making a Physics-Based Game 187
     Creating the Project 188
     Adding the Assets 189
     Adding the Levels 189
     Generating the Levels 190
     Making a Playable Game 197
     Creating the Cage 199
Summary 204

12 Making Apps with UIKit 205
Application Types 205
     Single-View Applications 206
     Creating the User Interface 208
     Adding Constraints 209
     Hooking Up the UI to Code 211
     Writing the Code 212
     The TableView 216
Summary 218

Index 219