Objective-C Fundamentals

More documents

Recommendations

Info

Using Xcode to develop a simple Coin Toss game 7 1.2.2 Expecting an unreliable internet connection In this age of cloud computing, a number of iOS applications need connectivity to the internet. The iOS platform provides two main forms of wireless connectivity: local area in the form of 802.11 Wi-Fi and wide area in the form of various cellular data standards. These connection choices provide a wide variability in speed, ranging from 300 kilobits to 54 megabits per second. It’s also possible for the connection to disappear altogether, such as when the user puts the device into flight mode, disables cellular roaming while overseas, or enters an elevator or tunnel. Unlike on a desktop, where most developers assume a network connection is always present, good iOS applications must be designed to cope with network connectivity being unavailable for long periods of time or unexpectedly disconnecting. The worst user experience your customers can have is a “sorry, cannot connect to server” error message while running late to a meeting and needing to access important information that shouldn’t require a working internet connection to obtain. In general, it’s important to constantly be aware of the environment in which your iOS application is running. Your development techniques may be shaped not only by the memory and processing constraints of the device but also by the way in which the user interacts with your application. That’s enough of the background information. Let’s dive right in and create an iOS application! 1.3 Using Xcode to develop a simple Coin Toss game Although you might have grand ideas for the next iTunes App Store smash, let’s start with a relatively simple application that’s easy to follow without getting stuck in too many technical details, allowing the unique features of the development tools to shine through. As the book progresses, we dig deeper into the finer points of everything demonstrated. For now the emphasis is on understanding the general process rather than the specifics of each technique. The application you develop here is a simple game that simulates a coin toss, such as is often used to settle an argument or decide who gets to go first in a competition. The user interface is shown in figure 1.2 and consists of two buttons labeled Heads and Tails. Using these buttons, the user can request that a new coin toss be made and call the desired result. The iPhone simulates the coin toss and updates the screen to indicate if the user’s choice is correct. In developing this game, the first tool we need to investigate is Xcode. Figure 1.2 game Coin Toss sample
8 CHAPTER 1 Building your first iOS application 1.3.1 Introducing Xcode—Apple’s IDE As mentioned earlier in this chapter, Xcode is an IDE that provides a comprehensive set of features to enable you to manage the entire lifecycle of your software development project. Creating the initial project, defining your class or data model, editing your source code, building your application, and finally debugging and performancetuning the resultant application are all tasks performed in Xcode. Xcode is built on the foundation of several open source tools: LLVM (the open source Low-Level Virtual Machine), GCC (the GNU compiler), GDB (the GNU debugger), and DTrace (instrumentation and profiling by Sun Microsystems). 1.3.2 Launching Xcode easily Once you install the iOS software development kit (SDK), the first challenge to using Xcode is locating the application. Unlike most applications that install in the/Applications folder, Apple separates developer-focused tools into the/Developer/Applications folder. The easiest way to find Xcode is to use the Finder to open the root Macintosh HD folder (as shown in figure 1.3). From there, you can drill down into the Developer folder and finally the Applications subfolder. As a developer, you’ll practically live within Xcode, so you may wish to put the Xcode icon onto your Dock or place the folder in the Finder sidebar for easy access. Once you locate the/Developer/Applications folder, you should be able to easily locate and launch Xcode. It’s important to note that Xcode isn’t your only option. Xcode provides all the features you require to develop applications out of the box, but that doesn’t mean you can’t complement it with your own tools. For example, if you have a favorite text editor in which you feel more productive, it’s possible to configure Xcode to use your external text editor in favor of the built-in functionality. The truly masochistic among you could even revert to using makefiles and the command line. Figure 1.3 A Finder window showing the location of the Developer folder, which contains all iPhone developer–related tools and documentation
Page 1 and 2: Christopher K. Fairbairn Johannes F
Page 4 and 5: Objective-C Fundamentals CHRISTOPHE
Page 6: PART 1 brief contents GETTING START
Page 9 and 10: viii CONTENTS 1.5 Compiling the Coi
Page 11 and 12: x CONTENTS 5.4 Declared properties
Page 13 and 14: xii CONTENTS PART 3 MAKING MAXIMUM
Page 16 and 17: preface Having been involved in the
Page 18 and 19: ACKNOWLEDGMENTS xvii Christopher wo
Page 20 and 21: ABOUT THIS BOOK xix skills. There
Page 22 and 23: author online Purchase of Objective
Page 24: Part 1 Getting started with Objecti
Page 27 and 28: 4 CHAPTER 1 Building your first iOS
Page 29: 6 CHAPTER 1 Building your first iOS
Page 33 and 34: 10 CHAPTER 1 Building your first iO
Page 51 and 52: Data types, variables, and constant
Page 53 and 54: 30 CHAPTER 2 Data types, variables,
Page 79 and 80: 56 CHAPTER 3 An introduction to obj
Page 81 and 82:
58 CHAPTER 3 An introduction to obj
Page 83 and 84:
Page 85 and 86:
Page 87 and 88:
Page 89 and 90:
Page 91 and 92:
Page 93 and 94:
Page 95 and 96:
Page 97 and 98:
Storing data in collections This ch
Page 99 and 100:
76 CHAPTER 4 Storing data in collec
Page 101 and 102:
Page 103 and 104:
Page 105 and 106:
Page 107 and 108:
Page 109 and 110:
Page 111 and 112:
Page 113 and 114:
Page 115 and 116:
Page 117 and 118:
Page 120 and 121:
Creating classes This chapter cover
Page 122 and 123:
Declaring the interface of a class
Page 124 and 125:
Page 126 and 127:
Page 128 and 129:
Page 130 and 131:
Providing an implementation for a c
Page 132 and 133:
Declared properties 109 - (Property
Page 134 and 135:
Declared properties 111 Let’s bri
Page 136 and 137:
Declared properties 113 Although @s
Page 138 and 139:
Creating and destroying objects 115
Page 140 and 141:
Page 142 and 143:
Page 144 and 145:
Using the class in the Rental Manag
Page 146 and 147:
Summary 123 a number of rental prop
Page 148 and 149:
Subclassing 125 the only class you
Page 150 and 151:
Adding new instance variables 127 s
Page 152 and 153:
Accessing existing instance variabl
Page 154 and 155:
Overriding methods 131 } return gen
Page 156 and 157:
Overriding methods 133 } "for $%@ p
Page 158 and 159:
Class clusters 135 Figure 6.2 Graph
Page 160 and 161:
Categories 137 This code tells the
Page 162 and 163:
Subclassing in your demo applicatio
Page 164 and 165:
Subclassing in your demo applicatio
Page 166 and 167:
Summary 143 6.8 Summary Object-orie
Page 168 and 169:
Defining a protocol 145 Mastering t
Page 170 and 171:
Implementing a protocol 147 7.2.1 C
Page 172 and 173:
Implementing a protocol 149 Listing
Page 174 and 175:
Important protocols 151 iPhone UIKi
Page 176 and 177:
Important protocols 153 executed. T
Page 178 and 179:
Important protocols 155 Any table v
Page 180 and 181:
Important protocols 157 or in table
Page 182 and 183:
Important protocols 159 For s
Page 184 and 185:
Important protocols 161 Listing 7.1
Page 186 and 187:
Dynamic typing and runtime type inf
Page 188 and 189:
Static vs. dynamic typing 165 If yo
Page 190 and 191:
How messaging works 167 Messages ar
Page 192 and 193:
How messaging works 169 8.3.2 Handl
Page 194 and 195:
Runtime type information 171 The if
Page 196 and 197:
Runtime type information 173 8.4.3
Page 198 and 199:
Practical uses of runtime type intr
Page 200 and 201:
Memory management This chapter cove
Page 202 and 203:
Reference counting 179 Figure 9.1 A
Page 204 and 205:
Reference counting 181 the object i
Page 206 and 207:
Reference counting 183 Keep yoursel
Page 208 and 209:
Autorelease pools 185 Ideally, you
Page 210 and 211:
Autorelease pools 187 With knowledg
Page 212 and 213:
Autorelease pools 189 i * 1000 + j]
Page 214 and 215:
Memory zones 191 Memory zones have
Page 216 and 217:
Responding to low-memory warnings 1
Page 218 and 219:
Page 220 and 221:
Page 222 and 223:
Summary 199 addObserver:selector:na
Page 224 and 225:
Part 3 Making maximum use of framew
Page 226 and 227:
Error and exception handling This c
Page 228 and 229:
NSError—handling errors the Cocoa
Page 230 and 231:
Creating NSError objects 207 chapte
Page 232 and 233:
Creating NSError objects 209 10.2.2
Page 234 and 235:
Summary 211 10.3.2 Catching excepti
Page 236 and 237:
Making your objects KVC-compliant 2
Page 238 and 239:
Making your objects KVC-compliant 2
Page 240 and 241:
Handling special cases 217 This que
Page 242 and 243:
Filtering and matching with predica
Page 244 and 245:
Page 246 and 247:
Page 248 and 249:
Sample application 225 rentingFor:2
Page 250 and 251:
Summary 227 The core of the logic o
Page 252 and 253:
Core Data history 229 Structured Qu
Page 254 and 255:
Core Data objects 231 In Xcode you
Page 256 and 257:
Core Data resources 233 careful to
Page 258 and 259:
Building the PocketTasks applicatio
Page 260 and 261:
Page 262 and 263:
Page 264 and 265:
Page 266 and 267:
Page 268 and 269:
Page 270 and 271:
Page 272 and 273:
Page 274 and 275:
Beyond the basics 251 How do you us
Page 276 and 277:
Beyond the basics 253 All you do is
Page 278 and 279:
Beyond the basics 255 attributeName
Page 280 and 281:
Blocks and Grand Central Dispatch T
Page 282 and 283:
The syntax of blocks 259 What if yo
Page 284 and 285:
The syntax of blocks 261 change the
Page 286 and 287:
The syntax of blocks 263 } [super d
Page 288 and 289:
Performing work asynchronously 265
Page 290 and 291:
Page 292 and 293:
Page 294 and 295:
Page 296 and 297:
Page 298 and 299:
Summary 275 more to learn about GCD
Page 300 and 301:
Building an application, complete w
Page 302 and 303:
Understanding NSLog 279 Figure 14.3
Page 304 and 305:
Bringing memory leaks under control
Page 306 and 307:
Bringing memory leaks under control
Page 308 and 309:
Detecting zombies 285 (and the appl
Page 310 and 311:
Summary 287 and its ease of use and
Page 312 and 313:
Preparing your iOS device for devel
Page 314 and 315:
Preparing your iOS device for devel
Page 316 and 317:
appendix B The basics of C Througho
Page 318 and 319:
Variable naming conventions 295 As
Page 320 and 321:
Expressions 297 Table B.3 Relationa
Page 322 and 323:
Expressions 299 B.2.4 Assignment op
Page 324 and 325:
Conditional statements 301 based on
Page 326 and 327:
Conditional statements 303 The gene
Page 328 and 329:
Looping statements 305 Not as strai
Page 330 and 331:
Looping statements 307 One importan
Page 332 and 333:
Looping statements 309 As in a do l
Page 334 and 335:
Summary 311 CONTINUE The continue s
Page 336 and 337:
A short history of Objective-C 313
Page 338 and 339:
The iPhone SDK: Safari 315 C.2 Alte
Page 340 and 341:
The iPhone SDK: Safari 317 C.3.2 ha
Page 342 and 343:
The iPhone SDK: Safari 319 It’s i
Page 344 and 345:
Scripting languages: Lua and Ruby 3
Page 346 and 347:
Mono (.NET) 323 the iOS platform. F
Page 348 and 349:
Summary 325 Xamarin announced a fol
Page 350 and 351:
index Symbols ^ operator 298 - oper
Page 352 and 353:
INDEX 329 application-specific quer
Page 354 and 355:
INDEX 331 collections (continued) e
Page 356 and 357:
INDEX 333 E e character 35 editButt
Page 358 and 359:
INDEX 335 iOS Developer account 9 i
Page 360 and 361:
INDEX 337 mutableCopyWithZone 190 M
Page 362 and 363:
INDEX 339 Organizer window 291 over
Page 364 and 365:
INDEX 341 setFlag 164 setNilValueFo
Page 366:
INDEX 343 vardic method 75 variable
show all

Objective-C Fundamentals

Create successful ePaper yourself

Delete template?

Save as template?