Datasheet

Getting Started

Developing for iOS

iOS development is more complicated than OS X development. Development is controlled by

provisioning, an Apple-generated security control, which is built into Xcode and manages

access to hardware testing and App Store distribution.

iPhone, iPod touch, and iPad platforms all use iOS, but these platforms are significantly different

and may not always run the same version of iOS. Even when they do run the same version, not

all hardware features and UI options are available on very device.

In extreme cases, conditional code is required to check which device an app is running on and

which version of iOS it supports. Code paths may need to be selected accordingly with manual

checks at runtime.

Apple is unlikely to simplify this process in future releases of Xcode. It’s more likely that the iOS

device range will expand, and apps will need to manage an ever-increasing selection of screen

sizes, hardware features, and operating systems.

The Xcode Simulator, shown in Figure 1.15, includes separate iPhone and iPad testing options,

but it is suitable only for apps that don’t use any of the iOS hardware features, such as the GPS

and the accelerometer. All but the very simplest commercial apps should be tested on real

hardware.

The extra requirements of provisioning and multi-platform support can make iOS development

feel challenging and complex. A further complication is the need to produce high-quality sup-

porting graphics and screen designs for maximum buyer impact in the App Store.

To date, Apple’s beta cycle for iOS has been more aggressive than for OS X, and it’s usual to

have a new beta preview of iOS available almost as soon as the most recent version has been

made public. Beta development requires a parallel version of Xcode and beta firmware for every

test device. It may also require an updated version of iTunes and OS X.

So although the iPhone and iPad are simpler than a Mac, and app code can be very much sim-

pler, you should allow extra time to work for projects to support all the different possible tar-

gets, versions, and security options.

Xcode supports these extra possibilities, but it doesn’t simplify them. Developing and testing a

universal iOS app—a single app that can run on an iPhone, an iPod, and an iPad—remains a

challenge.

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