Objective-C for Absolute Beginners: iPhone, iPad and Mac Programming Made Easy

292 Pages·2010·15.72 MB·English

by  James Bennett

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Objective-C for Absolute
Beginners
iPhone, iPad, and Mac Programming
Made Easy

■ ■ ■
Gary Bennett
Mitch Fisher
Brad Lees

i
Objective-C for Absolute Beginners: iPhone, iPad, and Mac Programming Made Easy
Copyright © 2010 by Gary Bennett, Mitch Fisher, Brad Lees
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ISBN-13 (pbk): 978-1-4302-2832-5
ISBN-13 (electronic): 978-1-4302-2833-2
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ii
I would like to dedicate this book to my wife Stefanie and to my children, Michael, Danielle,
Michelle, and Emily. Thank you for always supporting me when I decide to do crazy things like
write a book.
Also, I want to thank two of my friends, Mitch Fisher and Brad Lees, for co-authoring this book
with me. They are two of the finest developers in the country, and are great friends. It was great
being able to work with them again.
—Gary Bennett

I would like to thank all my family and friends who have patiently supported my work on this book.
You know who you are. I would like to especially thank Lisa, Jade, Eric, and Patti for the long
nights and forever-busy weekends that I was spending on this book and not with them.
—Mitch Fisher

I would like to thank my wife Natalie and my kids for the support and time they have given me to
work on this book. I am also grateful for good friends who convince me to take on crazy
endeavors.
—Brad Lees

iii
Contents at a Glance
■Contents at a Glance.......................................................................................iv
■Contents..........................................................................................................v
■About the Authors ...........................................................................................x
■About the Technical Reviewer........................................................................xi
■Acknowledgments.........................................................................................xii
■Introduction..................................................................................................xiii
■Chapter 1: Becoming a Great iPhone/iPad or Mac Programmer.....................1(cid:1)
■Chapter 2: Programming Basics...................................................................13(cid:1)
■Chapter 3: It’s All About the Data..................................................................37(cid:1)
■Chapter 4: Making Decisions About…and Planning Program Flow..............57(cid:1)
■Chapter 5: Object Oriented Programming with Objective-C..........................81(cid:1)
■Chapter 6: Introducing Objective-C and Xcode..............................................97(cid:1)
■Chapter 7: Objective-C Classes, Objects, and Methods...............................117(cid:1)
■Chapter 8: Programming Basics in Objective-C..........................................137(cid:1)
■Chapter 9: Comparing Data.........................................................................157(cid:1)
■Chapter 10: Creating User Interfaces with Interface Builder......................175(cid:1)
■Chapter 11: Memory, Addresses, and Pointers...........................................199(cid:1)
■Chapter 12: Debugging Programs with Xcode............................................219(cid:1)
■Chapter 13: Storing Information..................................................................237(cid:1)
■Chapter 14: Protocols and Delegates..........................................................257(cid:1)
■Index............................................................................................................263
iv
Contents
■Contents at a Glance.......................................................................................iv(cid:1)
■Contents..........................................................................................................v(cid:1)
■About the Authors ...........................................................................................x(cid:1)
■About the Technical Reviewer........................................................................xi(cid:1)
■Acknowledgments.........................................................................................xii
■Introduction..................................................................................................xiii(cid:1)

■Chapter 1: Becoming a Great iPhone/iPad or Mac Programmer.....................1(cid:1)
Thinking Like a Developer......................................................................................................................................1(cid:1)
Completing the Development Cycle........................................................................................................................4(cid:1)
Introducing Object Oriented Programming.............................................................................................................6(cid:1)
Working with the Alice Interface.............................................................................................................................8(cid:1)
Summary..............................................................................................................................................................11(cid:1)
Exercises...............................................................................................................................................................11(cid:1)
■Chapter 2: Programming Basics...................................................................13(cid:1)
Taking a Tour with Alice.......................................................................................................................................13(cid:1)
Navigation Menu..............................................................................................................................................14(cid:1)
World Window..................................................................................................................................................15(cid:1)
Classes, Objects, and Instances in Alice..........................................................................................................17(cid:1)
Object Tree.......................................................................................................................................................18(cid:1)
Editor Area.......................................................................................................................................................18(cid:1)
Details Area......................................................................................................................................................19(cid:1)
Events Area......................................................................................................................................................19(cid:1)
Creating an Alice App—To the Moon Alice...........................................................................................................20(cid:1)
Your First Objective-C Program............................................................................................................................26(cid:1)
Installing Xcode...............................................................................................................................................27(cid:1)
Launching and Using Xcode.............................................................................................................................30(cid:1)
Summary..............................................................................................................................................................35(cid:1)
Exercises...............................................................................................................................................................36(cid:1)

v
■ CONTENTS
■Chapter 3: It’s All About the Data..................................................................37(cid:1)
Numbering Systems Used in Programming..........................................................................................................37(cid:1)
Bits...................................................................................................................................................................37(cid:1)
Bytes................................................................................................................................................................39(cid:1)
Hexadecimal....................................................................................................................................................41(cid:1)
Unicode............................................................................................................................................................42(cid:1)
Data Types............................................................................................................................................................42(cid:1)
Using Variable and Data Types with Alice.............................................................................................................43(cid:1)
Data Types and Objective-C..................................................................................................................................50(cid:1)
Identifying Problems.............................................................................................................................................54(cid:1)
Summary..............................................................................................................................................................56(cid:1)
Exercises...............................................................................................................................................................56(cid:1)
■Chapter 4: Making Decisions About…and Planning Program Flow..............57(cid:1)
Boolean Logic.......................................................................................................................................................57(cid:1)
Truth Tables.....................................................................................................................................................59(cid:1)
Comparison Operators.....................................................................................................................................61(cid:1)
Designing Apps.....................................................................................................................................................62(cid:1)
Pseudo-code....................................................................................................................................................62(cid:1)
Design Requirements............................................................................................................................................64(cid:1)
Flowcharting....................................................................................................................................................67(cid:1)
Designing and Flowcharting an Example App.................................................................................................68(cid:1)
The App’s Design.............................................................................................................................................69(cid:1)
Using Loops to Repeat Program Statements...................................................................................................70(cid:1)
Coding the Example App in Alice..........................................................................................................................72(cid:1)
Coding the Example App in Objective-C................................................................................................................74(cid:1)
Nested If Statements and Else-If Statements.......................................................................................................77(cid:1)
Improving the Code Through Refactoring.............................................................................................................77(cid:1)
Moving Forward Without Alice..............................................................................................................................78(cid:1)
Summary..............................................................................................................................................................79(cid:1)
Exercises...............................................................................................................................................................80(cid:1)
■Chapter 5: Object Oriented Programming with Objective-C..........................81(cid:1)
The Object.............................................................................................................................................................81(cid:1)
What Is a Class.....................................................................................................................................................82(cid:1)
Planning Classes...................................................................................................................................................83(cid:1)
Inheritance............................................................................................................................................................93(cid:1)
Why Use OOP?......................................................................................................................................................94(cid:1)
Eliminate Redundant Code...............................................................................................................................94(cid:1)
Ease of Debugging...........................................................................................................................................95(cid:1)
Ease of Replacement.......................................................................................................................................95(cid:1)
Advanced Topics...................................................................................................................................................95(cid:1)
Interface...........................................................................................................................................................95(cid:1)
Polymorphism..................................................................................................................................................95(cid:1)
Summary..............................................................................................................................................................96(cid:1)
Exercises...............................................................................................................................................................96(cid:1)
■Chapter 6: Introducing Objective-C and Xcode..............................................97(cid:1)
A Brief History of Objective-C...............................................................................................................................97(cid:1)
Understanding C Language Basics.......................................................................................................................98(cid:1)
vi
■ CONTENTS
Putting the “Objective” into Objective-C.............................................................................................................100(cid:1)
Introducing Xcode...............................................................................................................................................105(cid:1)
Starting Up Xcode...............................................................................................................................................106(cid:1)
Creating Your First Project..................................................................................................................................107(cid:1)
Adding a New Class.......................................................................................................................................108(cid:1)
Building and Running the New Program........................................................................................................114(cid:1)
Summary............................................................................................................................................................115(cid:1)
Exercises.............................................................................................................................................................116(cid:1)
■Chapter 7: Objective-C Classes, Objects, and Methods...............................117(cid:1)
Creating an Objective-C Class............................................................................................................................117(cid:1)
Declaring Interfaces and Instance Variables.................................................................................................119(cid:1)
Sending Messages (Methods)........................................................................................................................119(cid:1)
Working with the Implementation File...........................................................................................................121(cid:1)
Implementing Methods..................................................................................................................................123(cid:1)
Using Our New Class...........................................................................................................................................125(cid:1)
Overriding Default Behavior...........................................................................................................................132(cid:1)
Taking Class Methods to the Next Level........................................................................................................133(cid:1)
Accessing the Xcode Documentation.................................................................................................................133(cid:1)
Summary............................................................................................................................................................134(cid:1)
Exercises.............................................................................................................................................................135(cid:1)
■Chapter 8: Programming Basics in Objective-C..........................................137(cid:1)
Creating a Simple Command Line Tool...............................................................................................................138(cid:1)
Introducing Instance Variables...........................................................................................................................140(cid:1)
Accessing Instance Variables........................................................................................................................141(cid:1)
Using Getter and Setter Methods...................................................................................................................142(cid:1)
Introducing Properties........................................................................................................................................144(cid:1)
Using Properties.............................................................................................................................................145(cid:1)
Understanding the Importance of Conventions..............................................................................................146(cid:1)
Creating the MyBookstore Program....................................................................................................................146(cid:1)
Using the NSMutableDictionary Class............................................................................................................148(cid:1)
Making Our Object Do Something..................................................................................................................149(cid:1)
Implementing Behavior..................................................................................................................................150(cid:1)
Cleaning Up Our Objects................................................................................................................................153(cid:1)
Using the Bookstore and Book Objects..........................................................................................................154(cid:1)
Summary............................................................................................................................................................156(cid:1)
Exercises.............................................................................................................................................................156(cid:1)
■Chapter 9: Comparing Data.........................................................................157(cid:1)
Introducing Boolean Logic..................................................................................................................................157(cid:1)
Using Relational Operators.................................................................................................................................158(cid:1)
Comparing Numbers......................................................................................................................................158(cid:1)
Using Boolean Expressions.................................................................................................................................163(cid:1)
Comparing Strings.........................................................................................................................................164(cid:1)
Comparing Dates...........................................................................................................................................166(cid:1)
Combining Comparisons................................................................................................................................168(cid:1)
Using the Switch Statement...............................................................................................................................168(cid:1)
Grouping Variables Together..............................................................................................................................170(cid:1)
NSArray..........................................................................................................................................................170(cid:1)
vii
■ CONTENTS
NSMutableArray.............................................................................................................................................171(cid:1)
NSDictionary..................................................................................................................................................172(cid:1)
NSMutableDictionary.....................................................................................................................................172(cid:1)
Summary............................................................................................................................................................173(cid:1)
Exercises.............................................................................................................................................................174(cid:1)
■Chapter 10: Creating User Interfaces with Interface Builder......................175(cid:1)
Understanding Interface Builder.........................................................................................................................176(cid:1)
The Model-View-Controller.................................................................................................................................177(cid:1)
Human Interface Guidelines (HIGs).....................................................................................................................179(cid:1)
Creating an Example iPhone App with Interface Builder....................................................................................180(cid:1)
Using Outlets..................................................................................................................................................185(cid:1)
Implementing an Action.................................................................................................................................186(cid:1)
Using Interface Builder..................................................................................................................................187(cid:1)
Document Window.........................................................................................................................................188(cid:1)
Library Window..............................................................................................................................................189(cid:1)
Inspector Window..........................................................................................................................................190(cid:1)
Creating the View...........................................................................................................................................191(cid:1)
Connecting the Outlets and Objects...............................................................................................................192(cid:1)
Connecting Actions and Objects....................................................................................................................193(cid:1)
Implementation File.......................................................................................................................................195(cid:1)
Broken Connections in Interface Builder............................................................................................................196(cid:1)
Summary............................................................................................................................................................198(cid:1)
Exercises.............................................................................................................................................................198(cid:1)
■Chapter 11: Memory, Addresses, and Pointers...........................................199(cid:1)
Understanding Memory.......................................................................................................................................200(cid:1)
Bits, Bytes, and Bases...................................................................................................................................200(cid:1)
Understanding Memory Address Basics.............................................................................................................204(cid:1)
Requesting Memory............................................................................................................................................208(cid:1)
Working with Automatic Variables and Pointers............................................................................................208(cid:1)
Deallocating Memory..........................................................................................................................................209(cid:1)
Using Special Pointers...................................................................................................................................210(cid:1)
Managing Memory in Objective-C.......................................................................................................................212(cid:1)
Using the Retain/Release Model....................................................................................................................212(cid:1)
Working with Implied Retain Messages.........................................................................................................214(cid:1)
Sending the dealloc Message........................................................................................................................215(cid:1)
If Things Go Wrong..............................................................................................................................................216(cid:1)
Summary............................................................................................................................................................217(cid:1)
Exercises.............................................................................................................................................................218(cid:1)
■Chapter 12: Debugging Programs with Xcode............................................219(cid:1)
Getting Started with Debugging..........................................................................................................................220(cid:1)
Setting Breakpoints.......................................................................................................................................220(cid:1)
Debugging Basics..........................................................................................................................................222(cid:1)
Working with the Debugger Controls.............................................................................................................223(cid:1)
Debugging a Program.........................................................................................................................................224(cid:1)
Using the Step Controls.................................................................................................................................225(cid:1)
Looking at the Thread Window and Call Stack..............................................................................................225(cid:1)
Debugging Variables......................................................................................................................................226(cid:1)
viii