Neil Smyth wrote:Although the technology marketplace appears to evolve at a rapid and continuous pace, much of this progress takes place in the form of incremental improvements. It is only once every 10 to 20 years that new technology truly results in sweeping changes to both the technology industry and consumer behavior. The late 1970s and early 1980s, for example, witnessed the introduction of the personal computer. The late 1990s, of course, saw the widespread adoption of the internet. A little over a decade later we are in the middle of yet another revolution in the form of smartphones and tablets.

In actual fact there are many similarities between the PC and smartphone revolutions. Both resulted in the widespread adoption of new technology by businesses and consumers alike. Both caused a massive surge of development activity resulting in large numbers of new applications being written. Perhaps most interestingly, however, both were triggered to a large extent by the actions of Apple, Inc. first with the introduction of the Apple II computer in 1977, then again 30 years later with the iPhone in 2007.

The iPhone and its peers in the smartphone market are remarkable technological achievements. In a device small enough to put in your pocket the iPhone can make phone calls, send and receive email, SMS and MMS messages, stream and play audio and video, detect movement and rotation, vibrate, adapt the display brightness based on the ambient lighting, surf the internet, run apps from a selection of hundreds of thousands, take high resolution photos, record video, tell you your exact location, provide directions to your chosen destination, play graphics intensive games and even detect when you put the device to your ear.

Perhaps the most amazing thing about the iPhone is that all of these capabilities and hardware features are available to you as an app developer. In fact, once you have an iPhone, an Intel-based Mac computer, the iOS SDK, a copy of the Xcode development environment and the necessary skills, the only limit to the types of apps you can create is your own imagination (and, of course, the restrictions placed on apps accepted into the Apple App Store).

The subject of this book is version 5 of the iOS operating system within the context of the iPhone. iOS 5 introduces a wide range of new opportunities for the iPhone application developer to utilize. Beginning with the basics, this book provides an overview of the iPhone hardware and the architecture of iOS 5. An introduction to programming in Objective-C is provided followed by an in-depth look at the design of iPhone applications and user interfaces. More advanced topics such as file handling, database management, graphics drawing and animation are also covered, as are touch screen handling, gesture recognition, multitasking, iAds integration, location management, local notifications, camera access and video and audio playback support. New iOS 5 specific features are also covered including page view controller implementation, iCloud based storage, Storyboard user interface design, image filtering with Core Image and Twitter integration.

The aim of this book, therefore, is to teach you the skills necessary to build your own apps for the iPhone. Assuming you have downloaded the iOS 5 SDK and Xcode, have an Intel-based Mac and some ideas for some apps to develop, you are ready to get started.