Sams Teach Yourself Objective-C in 24 Hours

Jesse Feiler is a developer, web designer, trainer, and author. He has been an Apple developer since 1985, and has worked with mobile devices starting with Apple’s Newton and continuing with the iOS products (iPhone, iPod touch, and iPad). His books include Sams Teach Yourself Core Data in 24 Hours, Data-Driven iOS Apps for iPad and iPhone with FileMaker Pro, Bento by FileMaker, and FileMaker Go (Sams/Pearson), Using FileMaker Bento (Sams/Pearson), FileMaker Pro in Depth (Sams/Pearson), Sams Teach Yourself Drupal in 24 Hours (Sams/Pearson), Get Rich with Apps!Your Guide to Reaching More Customers and Making Money NOW (McGraw-Hill), Database-Driven Web Sites (Harcourt), How to Do Everything with Web 2.0 Mashups (McGraw-Hill), iWork `09 for Dummies (Wiley), and The Bento Book (Sams/Pearson). He has written about Objective-C and the Apple frameworks in Rhapsody Developer’s Guide (AP Professional, 1997) and Mac OS X Developer’s Guide (Morgan Kaufmann, 2001). He is the author of MinutesMachine, the meeting management software for iPad. There are more details at champlainarts.com. A native of Washington DC, he has lived in New York City and currently lives in Plattsburgh, NY. He can be reached at northcountryconsulting.com.

Introduction    1

Who Should Read This Book    1

What This Book Covers    1

Downloading the Example Files    2

How This Book Is Organized    2

Part I: Getting Started with Objective-C

HOUR 1: Overview of Objective-C    7

Introducing Objective-C    7

Enrolling as an Apple Developer    8

Setting Up the Development Environment    11

Summary    19

Q&A    20

Workshop    20

HOUR 2: Object-Oriented Programming with Objective-C    23

Object-Oriented Programming in the Objective-C World    23

Creating C with Objects    26

Managing Inheritance in the Objective-C World    30

Summary    32

Q&A    32

Workshop    33

HOUR 3: Using Object-Oriented Features in Objective-C    35

Communicating to Methods with Messages    35

Allocating and Initializing Objects    39

Summary    40

Q&A    41

Workshop    41

HOUR 4: Organizing Projects with a Git Source Code Repository    43

Getting to Work with Xcode    43

Keeping Track of Your Source Code    47

Using a Remote Repository    62

Summary    66

Q&A    66

Workshop    66

HOUR 5: Using Compiler Directives    69

Exploring Your Project    69

Working with Compiler Directives    71

Using Objective-C Compiler Directives    77

Summary    78

Q&A    78

Workshop    78

Part II: Working with the Objective-C Basics

HOUR 6: Exploring Messaging and a Testbed App    81

Setting Up the Test App    81

Adding a Text Field and Connecting It to Your Code    85

Sending a Message to the Text Field    92

Reviewing the Message Syntax    94

Summary    95

Q&A    95

Workshop    95

HOUR 7: Declaring a Class in an Interface File    97

Letting Xcode Do the Work    97

Exploring Class Hierarchies    103

Declaring Classes    106

Summary    108

Q&A    108

Workshop    108

HOUR 8: Declaring Instance Variables in an Interface File    111

Declaring Instance Variables and Properties    111

Using the Class    111

Creating an Instance Variable for CurrencyConverter with id    114

Creating an Instance Variable for CurrencyConverter with the

Class Name    117

Creating an Instance Variable for CurrencyConverter with a

Superclass Name    119

Managing Instance Variable Scope    122

Summary    122

Q&A    123

Workshop    123

HOUR 9: Declaring Properties in an Interface File    125

Comparing Interface Variables and Properties    125

Using Declared Properties    130

Using Attributes    132

Using Other Attribute Decorators    135

Implementing Properties    135

Summary    136

Q&A    137

Workshop    137

HOUR 10: Declaring Methods in an Interface File    139

Working with Methods in a Class    139

Reviewing Method Syntax    140

Summary    145

Q&A    145

Workshop    146

HOUR 11: Declaring Actions in an Interface File    147

Introducing Actions    147

Comparing Actions in Mac OS X and iOS    158

Q&A    161

Workshop    161

HOUR 12: Routing Messages with Selectors    163

Getting Inside Objective-C Messages    163

Getting Inside the Objective-C Runtime    165

Working with SEL and @selector ()    166

Using performSelector    167

Using NSInvocation    170

Testing Whether an Instance Can Respond to a Selector    174

Summary    174

Q&A    175

Workshop    175

HOUR 13: Building on the Foundation    177

Exploring the Foundation Framework    177

Foundation Classes    178

Foundation Paradigms and Policies    180

Summary    185

Q&A    185

Workshop    185

HOUR 14: Defining a Class in an Implementation File    187

Working with a New Project    187

Creating a New App    191

Implementing a Method    194

Expanding the Class with init Methods    197

Summary    199

Q&A    200

Workshop    200

HOUR 15: Organizing Data with Collections    201

Collecting Objects    201

Getting Familiar with Property Lists    203

Comparing the Collection Classes    205

Creating a Collection    206

Enumerating a Collection    210

Testing Membership in a Collection    212

Accessing an Object in a Collection    213

Summary    213

Q&A    213

Workshop    214

HOUR 16: Managing Memory and Runtime Objects    215

Managing Objects in Memory    215

Managing Reference Counts Manually    217

Managing Reference Counts with ARC    220

Variable Qualifiers    222

Autoreleasing Variables    223

Summary    224

Q&A    224

Workshop    224

Part III: Expanding and Extending Classes

HOUR 17: Extending a Class with Protocols and Delegates    227

Exploring the Pros and Cons of Subclassing    227

Exploring Multiple Detail Views Sample Code    228

Looking Inside Protocols    235

Working with Delegates    235

Summary    240

Q&A    240

Workshop    240

HOUR 18: Extending a Class with Categories and Extensions    243

Comparing Categories and Protocols    243

Comparing Categories to Subclasses    244

Working with Categories    246

Using Class Extensions    249

Working with Informal Protocols    250

Summary    250

Q&A    250

Workshop    251

HOUR 19: Using Associative References and Fast Enumeration    253

Catching Up on Objective-C 2.0 Time-Saving Features    253

Extending Classes by Adding Instance Variables (Sort of)    254

Using Fast Enumeration    258

Summary    261

Q&A    261

Workshop    261

HOUR 20: Working with Blocks    263

Revisiting Blocks    263

Looking at Callbacks    264

Introducing Blocks    268

Exploring Blocks in Cocoa    270

Looking Deeper into Cocoa Blocks and Memory    273

Summary    273

Q&A    274

Workshop    274

Part IV: Beyond the Basics

HOUR 21: Handling Exceptions    275

Rethinking Exceptions and Errors    275

Introducing the Exception and Error Classes    276

Identifying an Exception    281

Throwing an Exception    282

Catching an Exception    283

Summary    283

Q&A    284

Workshop    284

HOUR 22: Grand Central Dispatch: Using Queues and Threading    285

Getting Started with Concurrency    285

Introducing Queues    288

Using Dispatch Queues    290

Summary    292

Q&A    293

Workshop    293

HOUR 23: Working with the Debugger    295

Logging Information    295

Using Console Logs    296

Using Smart Breakpoints    299

Summary    304

Q&A    304

Workshop    305

HOUR 24: Using Instruments for Analysis    307

Putting Instruments in Perspective    307

Looking at Instruments    309

Getting Started with Instruments    311

Connecting to the iOS Simulator    314

Summary    316

Q&A    316

Workshop    316

Part V: Appendixes

APPENDIX A: C Syntax Summary    319

Data Types    319

Control Structures    321

APPENDIX B: Apps, Packages, and Bundles    323

APPENDIX C: Archiving and Packaging Apps for Development and Testing    329

APPENDIX D: Introducing Xcode 4    333

Getting to Know Xcode    333

Goodbye “Hello, World”    334

Hello, App Development for Mac OS X and iOS    336

Getting Started with Xcode    338

Using the Navigator    341

Using Editors    351

Working with Assistant    355

Getting Help in an Editor Window    357

Using Utilities—Inspectors    357

Using Utilities—Libraries    360

Using the Text Editor    366

Using the Organizer Window    371

Index    375