Getting iPhone Apps to Run on the iPad

Rory Lewis
(The following article is an excerpt from "iPhone and iPad Apps for Absolute Beginners," published by Apress)

Right off the bat, let's understand what the iPad is all about. In fact, let's think about what all the Apple geeks were doing after the iPad was launched. Within the first 24 hours of the iPad's release, chances are many of the Mac-heads were scratching their heads and complaining. 'What's in it for me? There's nothing new here. This really sucks!' This crowd was tuned into the fact that, with their Macs and their iPhones, they had everything they needed already, and many of them quickly concluded that the iPad wouldn't be serving any immediate need.

Well, then, who is the target audience for the iPad?

Knowing why the iPad was developed, and for whom, will help you understand which kind and style of apps have the greatest chance at succeeding. I spent close to two years following the events that led up to the introduction of the iPad, from initial speculation, to whether it would be called the iTablet or the iSlate, to mid-release reports and news updates - everything.

Believe it or not, the iPad design is aimed at older users who are new to the computer world and who don't want to spend more than $1,000. These are people who have just figured out how to turn the computer on and off and use e-mail! The iPad is also targeted at young students in an attempt to outdo the Kindle. One of the iPad's primary goals is to make the purchase of textbooks obsolete by offering a digital bookstore, in the same manner that iTunes offers music. So there you have it: older and younger generations of users are the target markets, instead of the standard set of geeks that normally goes for high-tech devices.

In this book, I present you with the knowledge and techniques to create applications that work with the iPhone and the iPad. The app images in this book include the iPad Simulator, which inherently implies the iPhone Simulator. Be sure to check out the various figures that contain images of results, and study the differences between the iPad and the iPhone. It will be important to know how the iPad does differ from the iPhone.

Do Apps Both Run on the iPad and the iPhone?

All the apps illustrated in this book run on both the iPad and the iPhone. I know this because I personally tested them - not only on the simulators, but also on my actual devices. Some of the images could have been made with larger (higher resolution) files had they been of apps coded exclusively for the iPad, but I chose to keep everything compatible with both devices.

The best way to tell if a future app you create works for both the iPhone and iPad is to simply plug in your iPad to your Mac; iTunes will display the apps that work on the iPad (Figure 3-8).

More Screen Space

The physical dimensions of the iPad are a little more than twice the height of the iPhone, and slightly more than triple the width, but the depth is increased by only 1.1 millimeters! The result is a roughly six-fold increase in the surface area, at practically the same depth, so this is truly a much bigger device that still possesses an extremely slender and light body. The physical dimensions are not, however, the same as the display dimensions.

This extra space has very important implications. Most obviously, quite a bit more information can be presented to the user at any given time. This means the organizational mindset that programmers are using on their existing iPhone apps may not always translate directly to the new, relatively expansive platform. Also, it turns out that migration from iPhone to iPad involves classes - preprogrammed sub-routines - that are not shared between the devices, and accomplishing this may require some specialization inside applications. Handling the user interface changes and application programming interface (API) differences will be addressed a little later. Right now let's consider the implications of the increased real estate the iPad boasts.

The iPad has the ability to run iPhone applications without changing the code one iota. Moreover, the iPad can run these applications at double their original size using a magnification function. This makes the migration process nearly painless for current iPhone developers. However, we are dealing with much more here than an oversized iPhone! There are numerous legitimate improvements over the iPhone that went into this newer device - not just incremental change, but quantum change. Because of this, we want to leverage these improvements and knock the socks off our future users.

More screen space means more information and more eye candy. A user can now see multiple pieces of data at once without having to navigate through the application. More room for videos, pictures, text, or game graphics means more flexibility and longevity for your app. The iPad structure supports all of the same features of the iPhone, including UIKit, Core Graphics, Media Kit, and OpenGL ES. Simply put, these are tool kits from which a bunch of different applications can be built. The increased processing power and larger screen size, however, mean that the iPad - and therefore your apps - can do significantly more with the same set of tools.

This increase in screen area, with improved high-resolution multi-touch sensors, also means more space for the user to interact with your application - with finer articulation. Complex gestures can now be used to navigate and manipulate an application in ways that are impossible on the relatively small iPhone screen. Keep this in mind as your application begins to take shape.

What gestures make sense here? What kinds of input could trigger this or that? In addition to the increased ability to support input from key gestures that stand for shortcut commands, the large screen size makes toolbars and accessory views possible. Providing the user with a toolbar is no longer taboo, and this may actually be encouraged to help your users leverage the increased interface of the iPad.

When you take all of these changes collectively, it behooves us to carefully consider our applications' designs. The creativity you and your fellow programmers wield must not only take advantage of the ability to display greater quantities of information in an easy-to-read, intuitive format, it must border on a total reorganization and transformation of the user experience.

Add Comment      Leave a comment on this blog post
Aug 1, 2011 12:08 PM comment perdre du ventre comment perdre du ventre  says:
Very interesting points you have mentioned, thank you for putting up. Reply
Oct 21, 2011 8:10 AM recuperer son ex recuperer son ex  says:
Perfect piece of work you have done, this website is really cool with fantastic information. Reply
Dec 6, 2011 7:12 PM Anonymous Anonymous  says:
The new iOS5 Version of Dr. Lewis' is essentially the second edition of the book quoted above. This new book however focuses on storyboarding and iOS5. It will be on sale in February in bookstores but one can buy the eBook sooner. Check in here: Reply

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