You're reading from SwiftUI Essentials - iOS Edition Learn to Develop iOS Apps using SwiftUI, Swift 5 and Xcode 11

Product type Paperback

Published in Nov 2018

Publisher Packt

ISBN-13 9781951442057

Length 813 pages

Edition 1st Edition

Languages

Swift

Tools

iOS

Concepts

iOS Development

Author (1):

Neil Smyth

View More author details

Table of Contents (373) Chapters

1. Start Here. 1 FREE CHAPTER

1.1 For Swift Programmers 1

1.2 For Non-Swift Programmers. 2

1.3 Source Code Download. 2

1.4 Feedback. 2

1.5 Errata. 2

2. Joining the Apple Developer Program.. 3

2.1 Downloading Xcode 11 and the iOS 13 SDK. 3

2.2 Apple Developer Program.. 3

2.3 When to Enroll in the Apple Developer Program?. 4

2.4 Enrolling in the Apple Developer Program.. 4

2.5 Summary. 5

3. Installing Xcode 11 and the iOS 13 SDK. 7

3.1 Identifying Your macOS Version. 7

3.2 Installing Xcode 11 and the iOS 13 SDK. 8

3.3 Starting Xcode. 8

3.4 Adding Your Apple ID to the Xcode Preferences. 8

3.5 Developer and Distribution Signing Identities. 9

4. An Introduction to Xcode 11 Playgrounds. 11

4.1 What is a Playground?. 11

4.2 Creating a New Playground. 11

4.3 A Basic Swift Playground Example. 13

4.4 Viewing Results 15

4.5 Adding Rich Text Comments. 16

4.6 Working with Playground Pages 18

4.7 Working with UIKit in Playgrounds 18

4.8 Adding Resources to a Playground. 20

4.9 Working with Enhanced Live Views 21

4.10 Summary. 23

5. Swift Data Types, Constants and Variables. 25

5.1 Using a Swift Playground. 26

5.2 Swift Data Types 26

5.2.1 Integer Data Types 26

5.2.2 Floating Point Data Types. 27

5.2.3 Bool Data Type. 27

5.2.4 Character Data Type. 27

5.2.5 String Data Type. 28

5.2.6 Special Characters/Escape Sequences 29

5.3 Swift Variables 30

5.4 Swift Constants. 30

5.5 Declaring Constants and Variables 30

5.6 Type Annotations and Type Inference. 30

5.7 The Swift Tuple. 31

5.8 The Swift Optional Type. 32

5.9 Type Casting and Type Checking. 36

5.10 Summary. 38

6. Swift Operators and Expressions 39

6.1 Expression Syntax in Swift 39

6.2 The Basic Assignment Operator 39

6.3 Swift Arithmetic Operators 39

6.4 Compound Assignment Operators. 40

6.5 Comparison Operators 41

6.6 Boolean Logical Operators 42

6.7 Range Operators 42

6.8 The Ternary Operator 43

6.9 Bitwise Operators 44

6.9.1 Bitwise NOT. 44

6.9.2 Bitwise AND. 45

6.9.3 Bitwise OR. 45

6.9.4 Bitwise XOR. 45

6.9.5 Bitwise Left Shift 46

6.9.6 Bitwise Right Shift 46

6.10 Compound Bitwise Operators 47

6.11 Summary. 47

7. Swift Control Flow.. 49

7.1 Looping Control Flow.. 49

7.2 The Swift for-in Statement 49

7.2.1 The while Loop. 50

7.3 The repeat ... while loop. 51

7.4 Breaking from Loops 51

7.5 The continue Statement 52

7.6 Conditional Flow Control 52

7.7 Using the if Statement 53

7.8 Using if ... else … Statements 53

7.9 Using if ... else if ... Statements 54

7.10 The guard Statement 54

7.11 Summary. 55

8. The Swift Switch Statement 57

8.1 Why Use a switch Statement?. 57

8.2 Using the switch Statement Syntax. 57

8.3 A Swift switch Statement Example. 58

8.4 Combining case Statements. 58

8.5 Range Matching in a switch Statement 59

8.6 Using the where statement 60

8.7 Fallthrough. 60

8.8 Summary. 61

9. An Overview of Swift 5 Functions, Methods and Closures 63

9.1 What is a Function?. 63

9.2 What is a Method?. 63

9.3 How to Declare a Swift Function. 63

9.4 Implicit Returns from Single Expressions 64

9.5 Calling a Swift Function. 65

9.6 Handling Return Values 65

9.7 Local and External Parameter Names 65

9.8 Declaring Default Function Parameters 66

9.9 Returning Multiple Results from a Function. 67

9.10 Variable Numbers of Function Parameters. 67

9.11 Parameters as Variables 68

9.12 Working with In-Out Parameters 68

9.13 Functions as Parameters 69

9.14 Closure Expressions. 71

9.15 Closures in Swift 73

9.16 Summary. 73

10. The Basics of Object-Oriented Programming in Swift 75

10.1 What is an Instance?. 75

10.2 What is a Class?. 75

10.3 Declaring a Swift Class 75

10.4 Adding Instance Properties to a Class 76

10.5 Defining Methods 76

10.6 Declaring and Initializing a Class Instance. 78

10.7 Initializing and Deinitializing a Class Instance. 78

10.8 Calling Methods and Accessing Properties 79

10.9 Stored and Computed Properties. 80

10.10 Lazy Stored Properties 81

10.11 Using self in Swift 82

10.12 Understanding Swift Protocols 84

10.13 Opaque Return Types. 85

10.14 Summary. 86

11. An Introduction to Swift Subclassing and Extensions 87

11.1 Inheritance, Classes and Subclasses. 87

11.2 A Swift Inheritance Example. 87

11.3 Extending the Functionality of a Subclass 88

11.4 Overriding Inherited Methods 89

11.5 Initializing the Subclass 90

11.6 Using the SavingsAccount Class. 91

11.7 Swift Class Extensions 91

11.8 Summary. 92

12. An Introduction to Swift Structures. 93

12.1 An Overview of Swift Structures 93

12.2 Value Types vs. Reference Types 94

12.3 When to use Structures or Classes 96

12.4 Summary. 96

13. An Introduction to Swift Property Wrappers 97

13.1 Understanding Property Wrappers 97

13.2 A Simple Property Wrapper Example. 97

13.3 Supporting Multiple Variables and Types 99

13.4 Summary. 102

14. Working with Array and Dictionary Collections in Swift 103

14.1 Mutable and Immutable Collections 103

14.2 Swift Array Initialization. 103

14.3 Working with Arrays in Swift 104

14.3.1 Array Item Count 104

14.3.2 Accessing Array Items 105

14.4 Random Items and Shuffling. 105

14.5 Appending Items to an Array. 105

14.5.1 Inserting and Deleting Array Items. 105

14.6 Array Iteration. 106

14.7 Creating Mixed Type Arrays. 106

14.8 Swift Dictionary Collections 107

14.9 Swift Dictionary Initialization. 107

14.10 Sequence-based Dictionary Initialization. 108

14.11 Dictionary Item Count 108

14.12 Accessing and Updating Dictionary Items 109

14.13 Adding and Removing Dictionary Entries 109

14.14 Dictionary Iteration. 109

14.15 Summary. 110

15. Understanding Error Handling in Swift 5. 111

15.1 Understanding Error Handling. 111

15.2 Declaring Error Types 111

15.3 Throwing an Error 112

15.4 Calling Throwing Methods and Functions. 113

15.5 Accessing the Error Object 114

15.6 Disabling Error Catching. 114

15.7 Using the defer Statement 114

15.8 Summary. 115

16. An Overview of SwiftUI 117

16.1 UIKit and Interface Builder 117

16.2 SwiftUI Declarative Syntax 118

16.3 SwiftUI is Data Driven. 118

16.4 SwiftUI vs. UIKit 119

16.5 Summary. 120

17. Using Xcode in SwiftUI Mode. 121

17.1 Starting Xcode 11. 121

17.2 Creating a SwiftUI Project 122

17.3 Xcode in SwiftUI Mode. 122

17.4 The Preview Canvas 123

17.5 Preview Pinning. 125

17.6 Modifying the Design. 125

17.7 Editor Context Menu. 129

17.8 Previewing on Multiple Device Configurations 129

17.9 Running the App on a Simulator 131

17.10 Running the App on a Physical iOS Device. 132

17.11 Managing Devices and Simulators. 134

17.12 Enabling Network Testing. 135

17.13 Dealing with Build Errors. 135

17.14 Monitoring Application Performance. 135

17.15 Exploring the User Interface Layout Hierarchy. 136

17.16 Summary. 139

18. The Anatomy of a Basic SwiftUI Project 141

18.1 Creating an Example Project 141

18.2 UIKit and SwiftUI 141

18.3 The AppDelegate.swift File. 141

18.4 The SceneDelegate.swift File. 142

18.5 ContentView.swift File. 144

18.6 Assets.xcassets. 144

18.7 Info.plist 144

18.8 LaunchScreen.storyboard. 144

18.9 Summary. 144

19. Creating Custom Views with SwiftUI 145

19.1 SwiftUI Views. 145

19.2 Creating a Basic View.. 145

19.3 Adding Additional Views 146

19.4 Working with Subviews. 148

19.5 Views as Properties 149

19.6 Modifying Views 150

19.7 Working with Text Styles 150

19.8 Modifier Ordering. 152

19.9 Custom Modifiers 153

19.10 Basic Event Handling. 153

19.11 The onAppear and onDisappear Methods 154

19.12 Building Custom Container Views. 155

19.13 Summary. 156

20. SwiftUI Stacks and Frames 157

20.1 SwiftUI Stacks. 157

20.2 Spacers, Alignment and Padding. 159

20.3 Container Child Limit 161

20.4 Text Line Limits and Layout Priority. 162

20.5 SwiftUI Frames 164

20.6 Frames and the Geometry Reader 166

20.7 Summary. 167

21. Working with SwiftUI State, Observable and Environment Objects 169

21.1 State Properties 169

21.2 State Binding. 171

21.3 Observable Objects. 172

21.4 Environment Objects 174

21.5 Summary. 176

22. A SwiftUI Example Tutorial 177

22.1 Creating the Example Project 177

22.2 Reviewing the Project 178

22.3 Adding a VStack to the Layout 180

22.4 Adding a Slider View to the Stack. 180

22.5 Adding a State Property. 181

22.6 Adding Modifiers to the Text View.. 182

22.7 Adding Rotation and Animation. 183

22.8 Adding a TextField to the Stack. 185

22.9 Adding a Color Picker 185

22.10 Tidying the Layout 187

22.11 Summary. 190

23. SwiftUI Observable and Environment Objects – A Tutorial 191

23.1 About the ObservableDemo Project 191

23.2 Creating the Project 191

23.3 Adding the Observable Object 191

23.4 Designing the ContentView Layout 192

23.5 Adding the Second View.. 194

23.6 Adding Navigation. 195

23.7 Using an Environment Object 196

23.8 Summary. 198

24. SwiftUI Stack Alignment and Alignment Guides. 199

24.1 Container Alignment 199

24.2 Alignment Guides. 201

24.3 Using the Alignment Guides Tool 205

24.4 Custom Alignment Types 206

24.5 Cross Stack Alignment 209

24.6 ZStack Custom Alignment 212

24.7 Summary. 215

25. SwiftUI Lists and Navigation. 217

25.1 SwiftUI Lists 217

25.2 SwiftUI Dynamic Lists 219

25.3 SwiftUI NavigationView and NavigationLink. 221

25.4 Making the List Editable. 223

25.5 Summary. 226

26. A SwiftUI List and Navigation Tutorial 227

26.1 About the ListNavDemo Project 227

26.2 Creating the ListNavDemo Project 227

26.3 Preparing the Project 227

26.4 Adding the Car Structure. 228

26.5 Loading the JSON Data. 229

26.6 Adding the Data Store. 230

26.7 Designing the Content View.. 230

26.8 Designing the Detail View.. 233

26.9 Adding Navigation to the List 235

26.10 Designing the Add Car View.. 236

26.11 Implementing Add and Edit Buttons 239

26.12 Adding the Edit Button Methods. 241

26.13 Summary. 242

27. Building Tabbed Views in SwiftUI 243

27.1 An Overview of SwiftUI TabView.. 243

27.2 Creating the TabViewDemo App. 244

27.3 Adding the TabView Container 244

27.4 Adding the Content Views 244

27.5 Adding the Tab Items. 244

27.6 Adding Tab Item Tags. 245

27.7 Summary. 246

28. Building Context Menus in SwiftUI 247

28.1 Creating the ContextMenuDemo Project 247

28.2 Preparing the Content View.. 247

28.3 Adding the Context Menu. 248

28.4 Testing the Context Menu. 249

28.5 Summary. 250

29. Basic SwiftUI Graphics Drawing. 251

29.1 Creating the DrawDemo Project 251

29.2 SwiftUI Shapes 251

29.3 Using Overlays 254

29.4 Drawing Custom Paths and Shapes 254

29.5 Drawing Gradients. 257

29.6 Summary. 260

30. SwiftUI Animation and Transitions 261

30.1 Creating the AnimationDemo Example Project 261

30.2 Implicit Animation. 261

30.3 Repeating an Animation. 264

30.4 Explicit Animation. 264

30.5 Animation and State Bindings 265

30.6 Automatically Starting an Animation. 266

30.7 SwiftUI Transitions. 269

30.8 Combining Transitions 270

30.9 Asymmetrical Transitions 271

30.10 Summary. 271

31. Working with Gesture Recognizers in SwiftUI 273

31.1 Creating the GestureDemo Example Project 273

31.2 Basic Gestures. 273

31.3 The onChange Action Callback. 275

31.4 The updating Callback Action. 276

31.5 Composing Gestures 278

31.6 Summary. 280

32. Integrating UIViews with SwiftUI 281

32.1 SwiftUI and UIKit Integration. 281

32.2 Integrating UIViews into SwiftUI 282

32.3 Adding a Coordinator 283

32.4 Handling UIKit Delegation and Data Sources. 284

32.5 An Example Project 286

32.6 Wrapping the UIScrolledView. 286

32.7 Implementing the Coordinator 287

32.8 Using MyScrollView.. 288

32.9 Summary. 289

33. Integrating UIViewControllers with SwiftUI 291

33.1 UIViewControllers and SwiftUI 291

33.2 Creating the ViewControllerDemo project 291

33.3 Wrapping the UIImagePickerController 291

33.4 Designing the Content View.. 293

33.5 Completing MyImagePicker 294

33.6 Completing the Content View.. 296

33.7 Testing the App. 297

33.8 Summary. 297

34. Integrating SwiftUI with UIKit 299

34.1 An Overview of the Hosting Controller 299

34.2 A UIHostingController Example Project 300

34.3 Adding the SwiftUI Content View. 300

34.4 Preparing the Storyboard. 301

34.5 Adding a Hosting Controller 302

34.6 Configuring the Segue Action. 304

34.7 Embedding a Container View.. 306

34.8 Embedding SwiftUI in Code. 308

34.9 Summary. 310

35. Preparing and Submitting an iOS 13 Application to the App Store. 311

35.1 Verifying the iOS Distribution Certificate. 311

35.2 Adding App Icons 313

35.3 Designing the Launch Screen. 314

35.4 Assign the Project to a Team.. 314

35.5 Archiving the Application for Distribution. 315

35.6 Configuring the Application in iTunes Connect 316

35.7 Validating and Submitting the Application. 317

35.8 Configuring and Submitting the App for Review.. 320

An Introduction to Swift Playgrounds

Working with Array and Dictionary Collections in Swift

The Swift Switch Statement

Swift Control Flow

The Basics of Object-Oriented Programming in Swift

Creating Custom Views with SwiftUI

Integrating UIViews with SwiftUI

Installing Xcode 11 and the iOS 13 SDK

SwiftUI Stacks and Frames

Joining the Apple Developer Program

An Overview of Swift 5 Functions, Methods and Closures

SwiftUI Stack Alignment and Alignment Guides

A SwiftUI Example Tutorial

SwiftUI Observable and Environment Objects – A Tutorial

SwiftUI Lists and Navigation

The Anatomy of a Basic SwiftUI Project

SwiftUI Animation and Transitions

Working with SwiftUI State, Observable and Environment Objects

A SwiftUI List and Navigation Tutorial

Integrating UIViewControllers with SwiftUI

Integrating SwiftUI with UIKit

21. Working with SwiftUI State, Observable and Environment Objects

Earlier chapters have described how SwiftUI emphasizes a data driven approach to app development whereby the views in the user interface are updated in response to changes in the underlying data without the need to write handling code. This approach is achieved by establishing a publisher and subscriber binding between the data and the views in the user interface.

SwiftUI offers three options for implementing this behavior in the form of state properties, observable objects and environment objects, all of which provide the state that drives the way the user interface appears and behaves. In SwiftUI, the views that make up a user interface layout are never updated directly within code. Instead, the views are updated automatically based on the state objects to which they have been bound as they change over time.

This chapter will describe these three options and outline when they should be used. Later chapters (A SwiftUI...

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Table of Contents (373) Chapters

21. Working with SwiftUI State, Observable and Environment Objects

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