The Advanced iOS 6 Developer's Cookbook

Erica Sadun is the bestselling author, coauthor, and contributor to several dozen books on programming, digital video and photography, and web design, including the widely popular The iOS 5 Developer’s Cookbook. She currently blogs at TUAW.com and has blogged in the past at O’Reilly’s Mac Devcenter, Lifehacker, and Ars Technica. In addition to being the author of dozens of iOS-native applications, Erica holds a Ph.D. in Computer Science from Georgia Tech’s Graphics, Visualization, and Usability Center. A geek, a programmer, and an author, she’s never met a gadget she didn’t love. When not writing, she and her geek husband parent three geeks-in-training, who regard their parents with restrained bemusement, when they’re not busy rewiring the house or plotting global dominance.

Preface   xiii

1 Device-Specific Development   1

Accessing Basic Device Information   1

Adding Device Capability Restrictions   2

Recipe: Checking Device Proximity and Battery States   5

Recipe: Recovering Additional Device Information   9

Recipe: Using Acceleration to Locate “Up”   11

Working with Basic Orientation   12

Retrieving the Current Accelerometer Angle Synchronously   13

Recipe: Using Acceleration to Move Onscreen Objects   16

Recipe: Accelerometer-Based Scroll View   19

Recipe: Core Motion Basics   21

Recipe: Retrieving and Using Device Attitude   26

Detecting Shakes Using Motion Events   27

Recipe: Using External Screens   29

Tracking Users   35

One More Thing: Checking for Available Disk Space  35

Summary   36

2 Documents and Data Sharing   39

Recipe: Working with Uniform Type Identifiers   39

Recipe: Accessing the System Pasteboard   45

Recipe: Monitoring the Documents Folder   48

Recipe: Presenting the Activity View Controller   54

Recipe: The Quick Look Preview Controller   63

Recipe: Adding a QuickLook Action   66

Recipe: Using The Document Interaction Controller   69

Recipe: Declaring Document Support   75

Recipe: Creating URL-Based Services   82

Summary   84

3 Core Text   87

Core Text and iOS   87

Attributed Strings   89

Recipe: Basic Attributed Strings   93

Recipe: Mutable Attributed Strings   95

The Mystery of Responder Styles   98

Recipe: Attribute Stacks   100

Recipe: Using Pseudo-HTML to Create Attributed Text   105

Drawing with Core Text   109

Creating Image Cut-Outs   112

Recipe: Drawing Core Text onto a Scroll View   114

Recipe: Exploring Fonts   116

Adding Custom Fonts to Your App   118

Recipe: Splitting Core Text into Pages   119

Recipe: Drawing Attributed Text into a PDF   120

Recipe: Big Phone Text   122

Summary   125

4 Geometry   127

Recipe: Retrieving Points from Bezier Paths   127

Recipe: Thinning Points   129

Recipe: Smoothing Drawings   132

Recipe: Velocity-Based Stroking   135

Recipe: Bounding Bezier Paths   137

Recipe: Fitting Paths   142

Working with Curves   144

Recipe: Moving Items Along a Bezier Path   148

Recipe: Drawing Attributed Text Along a Bezier Path   151

Recipe: View Transforms   154

Recipe: Testing for View Intersection   161

Summary   166

5 Networking   167

Recipe: Secure Credential Storage   167

Recipe: Entering Credentials   171

Recipe: Handling Authentication Challenges   176

Recipe: Uploading Data   177

Recipe: Building a Simple Web Server   181

Recipe: OAuth Utilities   184

Recipe: The OAuth Process   188

Summary   196

6 Images   197

Image Sources   197

Reading Image Data   199

Recipe: Fitting and Filling Images   203

Recipe: Rotating Images   208

Recipe: Working with Bitmap Representations   210

Recipe: Basic Image Processing   215

Recipe: Image Convolution   216

Recipe: Basic Core Image Processing   219

Capturing View-Based Screen Shots   221

Drawing into PDF Files   222

Recipe: Reflection   223

Recipe: Emitters   226

Summary   228

7 Cameras   229

Recipe: Snapping Photos   229

Recipe: Enabling a Flashlight   233

Recipe: Accessing the AVFoundation Camera   235

Recipe: EXIF   242

Image Orientations   247

Recipe: Core Image Filtering   249

Recipe: Core Image Face Detection   251

Recipe: Sampling a Live Feed   257

Summary   260

8 Audio   261

Recipe: Playing Audio with AVAudioPlayer   261

Recipe: Looping Audio   269

Recipe: Handling Audio Interruptions   272

Recipe: Recording Audio   274

Recipe: Recording Audio with Audio Queues   280

Recipe: Picking Audio with the MPMediaPickerController   286

Creating a Media Query   288

Recipe: Using the MPMusicPlayerController   290

Summary   294

9 Connecting to the Address Book   297

The AddressBook Frameworks   297

Recipe: Searching the Address Book   322

Recipe: Accessing Contact Image Data   325

Recipe: Picking People   326

Recipe: Limiting Contact Picker Properties   329

Recipe: Adding and Removing Contacts   331

Modifying and Viewing Individual Contacts   334

Recipe: The “Unknown” Person Controller   335

Summary   338

10 Location   339

Authorizing Core Location   339

Recipe: Core Location in a Nutshell   344

Recipe: Geofencing     348

Recipe: Keeping Track of “North” by Using Heading Values   350

Recipe: Forward and Reverse Geocoding   353

Recipe: Viewing a Location   355

Recipe: User Location Annotations   360

Recipe: Creating Map Annotations   363

Summary   369

11 GameKit   371

Enabling Game Center   371

Recipe: Signing In to Game Center   373

Designing Leaderboards and Achievements   375

Recipe: Accessing Leaderboards   378

Recipe: Displaying the Game Center View Controller   380

Recipe: Submitting Scores   381

Recipe: Checking Achievements   382

Recipe: Reporting Achievements to Game Center   383

Recipe: Multiplayer Matchmaking   385

Recipe: Responding to the Matchmaker   387

Recipe: Creating an Invitation Handler   388

Managing Match State     390

Recipe: Handling Player State Changes   390

Recipe: Retrieving Player Names   392

Game Play   393

Serializing Data   394

Recipe: Synchronizing Data   397

Recipe: Turn-by-Turn Matchmaking   399

Recipe: Responding to Turn-Based Invitations  401

Recipe: Loading Matches   402

Recipe: Responding to Game Play   403

Recipe: Ending Gameplay   407

Recipe: Removing Matches   410

Recipe: Game Center Voice   411

GameKit Peer Services   415

Summary   425

12 StoreKit   427

Getting Started with StoreKit   427

Creating Test Accounts   430

Creating New In-App Purchase Items   431

Building a Storefront GUI   435

Purchasing Items   438

Validating Receipts   443

Summary   445

13 Push Notifications   447

Introducing Push Notifications   447

Provisioning Push   451

Registering Your Application   454

Recipe: Push Client Skeleton   458

Building Notification Payloads   465

Recipe: Sending Notifications   466

Feedback Service   471

Designing for Push   473

Summary     473

Index   475