Creating iPhone Apps with Cocoa Touch: The Mini Missing Manual by Craig Hockenberry Copyright © 2010 O’Reilly Media, Inc. All rights reserved. Published by O’Reilly Media, Inc., 1005 Gravenstein Highway North, Sebastopol, CA 95472. O’Reilly Media books may be purchased for educational, business, or sales promotional use. Online editions are also available for most titles: safari. oreilly.com. For more information, contact our corporate/institutional sales department: 800-998-9938 or
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May 2010:
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ISBN: 9781449388409
Table of Contents
Introduction .......................................................................................v Building Your First iPhone App....................................................... 1 Getting the Tools..............................................................................................................................1 Installing Xcode.......................................................................................................................3 Getting the iPhone SDK..........................................................................................................6 What Lies Ahead for the SDK?............................................................................................11 Exploring Your New Tools............................................................................................................15 Every Flashlight Needs a Parts List.....................................................................................15 Some Assembly Required....................................................................................................21 Taking It for a Run on Your Mac..........................................................................................23 Revision Decision..................................................................................................................26
The Power of Brackets ................................................................... 33 Objective-C: The Nuts and Bolts for Your iPhone App............................................................34 The Land of Square Brackets...............................................................................................34 The Object of It All........................................................................................................................36 Telling Your Objects to Do Things.......................................................................................37 Masses of Classes..........................................................................................................................39 Classes in Detail.....................................................................................................................40 The Methods Behind the Madness.............................................................................................45 Categorically Speaking.........................................................................................................46 Implementation: The Brains Behind the Beauty...............................................................48 Creating New Classes...................................................................................................................50 Managing Memory........................................................................................................................53 Take a nil Pill .........................................................................................................................56 Autorelease with Ease..........................................................................................................58 Properties and Dots..............................................................................................................60
Methods of Class...........................................................................................................................62 Initializing Objects.........................................................................................................................64 Deallocation Location...........................................................................................................65 Loops: For Better or For Worse .................................................................................................66 Your Exceptional Code..................................................................................................................67 Learn by Crashing.................................................................................................................69 Selector Projector..........................................................................................................................73 Show Your id ................................................................................................................................75 Where to Go from Here...............................................................................................................79 Developer Documentation...................................................................................................80 Learn To Be Lazy...................................................................................................................84
Cocoa Touch: Putting Objective-C to Work.................................. 87 Get in Cocoa Touch.......................................................................................................................88 The Big Three: Models, Views, Controllers................................................................................89 Views.......................................................................................................................................91 Models....................................................................................................................................91 Controllers..............................................................................................................................92 Value Objects.................................................................................................................................94 Let’s Get Primitive.................................................................................................................95 Objectified..............................................................................................................................96 Collections....................................................................................................................................100 Copying in Depth................................................................................................................102 Property Lists.......................................................................................................................102 Mutable vs. Immutable...............................................................................................................103 Make It Mutable..................................................................................................................104 Protect Your Data................................................................................................................106 Delegation and Data Sources....................................................................................................107 Targets and Actions..................................................................................................................... 110 User Interface: The Hard Way........................................................................................... 112 User Interface: The Easy Way............................................................................................ 119 Notifications.................................................................................................................................135 Singletons.....................................................................................................................................139 Singletons as Globals ........................................................................................................140 Where to Go from Here.............................................................................................................142 The Language of Design.....................................................................................................142
Colophon ........................................................................................143
Introduction
Since the iTunes App Store’s launch in July 2008, developers have submitted over 100,000 iPhone applications to the store, resulting in over 3 billion downloads and climbing. Who wouldn’t want a piece of that action? Before the app store was launched, iPhone app development was limited to the engineers at Apple headquarters in Cupertino, Califormia. Now that Apple has released the developer tools to anyone who wants to download them, thousands of developers have discovered how easy and fun it is to write software for the iPhone. If you’ve done any programming in C or a related language like C++, Java, PHP, or Perl, you can learn to write iPhone apps in a snap. Objective-C will feel wonderfully familiar, since its entire infrastructure is based on standard C. In iPhone App Development: The Mini Missing Manual, you’ll create your first iPhone app right from the get-go, and get up to speed fast on all of your tools—Cocoa Touch, Interface Builder, Xcode, and Objective-C. Tip: There’s more to producing your own app than just writing the code. This eBook is ideal if the Cocoa Touch programming interface is all you want help with. For the full story on creating and selling a successful app—designing, programming, troubleshooting, submitting, and marketing—check out iPhone App Development: The Missing Manual. It covers everything in this Mini Manual, plus the entire lifecycle of an iPhone app.
Chapter 1
Building Your First iPhone App You have an idea that will lead to fame and fortune on the iTunes App Store. You decide to write an iPhone app. The first and most important task is for you to become comfortable with the tools used to build your products. A Chinese proverb says, “the journey is the reward,” and this chapter is all about the journey. In the upcoming pages, you’ll experience the entire application development process, start to finish. You’ll learn how to set up the software you need, and try your hand at building an app. But what app? If you do a quick search of the App Store, you’ll find no shortage of flashlights. For many aspiring developers, this simple application is a rite of passage, so now’s your chance to join this illustrious crowd. Once you see how easy it is to create your own app, you’ll wonder why people pay 99¢ for them on iTunes!
Getting the Tools You can’t build anything, including an iPhone app, without tools. Luckily, you can find everything you need on your Mac, or download it for free. Specifically, you need to download and install Xcode development software and the iPhone Software Development Kit (SDK) on your Mac. (And if you don’t have a Mac, see the box on page 2.)
Chapter 2
The Power of Brackets
You’ve now seen how easy it is to build an iPhone app: It’s not rocket science. Or is it? Apple has done an excellent job of creating the tools you use for building iPhone applications, but if you’re going to become a master craftsperson, you need to learn more about these new tools. The first section of this chapter will get you started in this exploration: You’re going to take a look the basics of the Objective-C language used to create apps. Also, a thriving community of developers is working on the iPhone. You’ll learn where to look for help with your coding questions, how to keep up with the ever evolving technologies used in the iPhone, and where to download free sample code to use in your own app development.
Chapter 3
Cocoa Touch: Putting Objective-C to Work
Now that you’ve gotten a taste of Objective-C, it’s time to put the language to work. If you think of Objective-C as the glue for building applications, you’re now going to explore the building blocks—parts of the Cocoa Touch frameworks—that get pieced together with your new adhesive. Before you start gluing the components of the Cocoa Touch frameworks together, you’ll need to learn a bit about the architecture and design patterns recommended by Apple’s engineers. Just as knowing how the correct building materials work together helps to build a house, a good working knowledge of the frameworks lets you build more robust applications and save time. You’ll also learn where to look for more information about Cocoa Touch. Plenty of resources on the Web and in your favorite bookstore can help you improve your iPhone development skills.
