Iphone Application Development for Dummies (Paperback)

Chapter 1
Creating Killer iPhone Applications
In This Chapter
? Figuring out what makes an insanely great iPhone application
? Listing the features of the iPhone that can inspire you
? Coming up against the limitations you have to live with
? Checking out the possibilities that are open to you
? Developing iPhone software now rather than later
Imagine that you’ve just landed at Heathrow Airport. It’s early in the morning, and you’re dead tired as you clear customs. All you want to do now is find the fastest way to get into London, check into your hotel, and sleep for a few hours. You take out your iPhone and touch the MobileTravel411 icon. On the left in Figure 1-1, you can see it asks whether you want to use Heathrow Airport as your current location. You touch Yes, and then touch Getting To From (as you can see in the center of Figure 1-1). Since it already knows that you’re at Heathrow, it gives you your alternatives. Because of the con

Chapter 1
Creating Killer iPhone Applications
In This Chapter
? Figuring out what makes an insanely great iPhone application
? Listing the features of the iPhone that can inspire you
? Coming up against the limitations you have to live with
? Checking out the possibilities that are open to you
? Developing iPhone software now rather than later
Imagine that you’ve just landed at Heathrow Airport. It’s early in the morning, and you’re dead tired as you clear customs. All you want to do now is find the fastest way to get into London, check into your hotel, and sleep for a few hours. You take out your iPhone and touch the MobileTravel411 icon. On the left in Figure 1-1, you can see it asks whether you want to use Heathrow Airport as your current location. You touch Yes, and then touch Getting To From (as you can see in the center of Figure 1-1). Since it already knows that you’re at Heathrow, it gives you your alternatives. Because of the congestion in and out of London, it suggests using the Heathrow Express, especially during rush hour. You touch the Heathrow Express tab and it tells you where to get the train and also tells you that the fare is £14.50 if you buy it from the ticket machine and £17.50 if you buy it on board the train. (The iPhone on the right in Figure 1-1 is proof that I’m not making this up.) It turns out that you’re so jetlagged that you can’t do the math in your head so you touch the Currency button and it tells you that £14.50 is around $21.35 if you took it from the ATM, $21.14 on your no-exchange-rate-fee credit card, or $22.31 at the bureau de change at the airport. Another touch gets you the current weather, which prompts you to dig out a sweater from your luggage before you get on the train. COPYRIGHTED MATERIAL 10 Part I: Getting Started When you get to Paddington Station, you really don’t have a clue where the hotel that someone at the office booked for you might be. You touch Getting Around, and the application allows you to use the hotel address that is in your iPhone Contacts, and then gives you your options when it comes to finally finding that big, comfortable, English bed. These include walking, taking a taxi, and public transit. You touch Tube and it directs you to the nearest Tube stop, and then displays fares, schedules, and how to buy a ticket. Figure 1-1: The Mobile- Travel411 application can use your current location. How much of a fantasy is this? Not much. Except for automatically determining your location and giving you public-transit directions as well as real-time exchange rates (stuff I’ll be adding in the near future) this application already exists. What’s more, it took me only a little over two months to develop that application, starting from where you are now, with no iPhone programming experience. What Makes a Great iPhone Application You’ll find a lot of different kinds of applications on the iPhone, ranging from utilities like the Weather Application, to games, to the New York Times reader, to the application I just described. Each one of these applications also falls on another continuum. At one end of this continuum is what I think of as the mobile desktop. These are applications you might use if you were using your desktop or laptop — applications you could port to (rewrite for) the iPhone. For example, I have a Chapter 1: Creating Killer iPhone Applications 11 weather application on my MacBook Pro on which I can read the New York Times as well — and it doesn’t take any major imaginative leap to see how one can do the Weather/New York Times thing on an iPhone. Although I wouldn’t think about writing this book on my iPhone, I can easily picture the iPhone as a handy home for note-taking applications, spreadsheet apps, and even stock-trading apps. At the other end of this continuum are those applications that you would never want to do on the desktop (or even a laptop), either because you don’t have the hardware or because, even if you did, doing it that way would be way too inconvenient. Imagine being at Heathrow, dead tired, taking out your laptop in the middle of a crowded terminal, powering it up, launching the application, and then navigating through it with the touch pad to get the information I got easily while holding the iPhone in one hand. I want that kind of information quickly and conveniently; I don’t want to have to dig my way to it through menus or layers of screens (or even going through the hassle of finding a wireless Internet connection). Seconds count. By the time any road warrior tied to a laptop did this at Heathrow, I would already be on the Heathrow Express. I like to think of these kinds of applications as here-and-now applications. You want to do a specific task, with up-to-date information, which the iPhone can access over the Internet through a cell network or Wi-Fi connection. You may even want the information or tasks tailored to where you are, which the iPhone can determine with its location hardware. With all that in mind, I can think of two things that you need to consider — besides functionality, of course — when it comes to creating a great iPhone application: ? Create a compelling user experience. ? Exploit the platform. The next few sections dig a little into my Two-Part Rule of Great iPhone Applications. Creating a Compelling User Experience The iPhone allows an immediacy and intimacy as it blends mobility and the power of the desktop to create a new kind of freedom. I like to use the term user experience because it implies more than a pretty user interface and nice graphics. A compelling user experience enables users to do what they need to do with a minimum of fuss and bother. But more than that, it forces you to think past a clean interface and even beyond basic convenience (such as not having to scroll through menus to do something simple). It includes meeting the expectations of the user based on the context — all the stuff going on around a user — in which they are using the application. 12 Part I: Getting Started A guidebook application may have a great user interface, for example, but it may not give me the most up-to-date information, or let me know a tour of Parliament is leaving in 5 minutes from the main entrance. Without those added touches, I’m just not willing to consider an app compelling. Exploiting the Platform The iPhone’s unique software and hardware allow you to create an application that enables the user to do something that may not be practical, or even possible with a laptop computer. Although the iPhone is a smaller, mobile personal computer, it is not a replacement for one. It is not intended to produce documents, proposals, or research. The iPhone has the capability to be an extension of the user, seamlessly integrated into his or her everyday life, and able to accomplish a singly focused task, or step in a series of tasks, in real time, based on where he or she is. Device-guided design While the enormous capabilities of the iPhone that make it possible to deliver the compelling user experience, you must take into account the limitations of the device as well. Keeping the two in balance is device-guided design. The next two sections describe both the features and limitations of the iPhone — and how to take them into account as you plan and develop an application. But understanding these constraints can also inspire you to create some really innovative applications. After a closer look at device-guided design, I come back to what makes a compelling user experience. Exploiting the features One of the keys to creating a great application is to take advantage of what the device offers. In the case of a new platform with new possibilities, such as the iPhone, this is especially important. Think about the possibilities that open up to you when your application can easily do the following: ? Access the Internet ? Know the location of the user ? Track orientation and motion ? Track the action of the user’s fingers on the screen ? Play audio and video ? Access the user’s contacts ? Access the user’s pictures and camera Chapter 1: Creating Killer iPhone Applications 13 Accessing the Internet The ability to access Web sites and servers on the Internet allows you to create applications that can provide real-time information to the user. It can tell me, for example, that the next tour at the Tate Modern is at 3:00 o’clock. This kind of access also allows you, as the developer, to go beyond the limited memory and processing power of the device and access large amounts of data stored on servers, or even offload the processing. I don’t have to have all the information for every city in the world stored on my iPhone, and don’t have to strain the poor CPU to compute the best way to get someplace on the Tube. I can send the request to a server and have it do all that work. This is client-server computing — a well established software architecture where the client provides a way to make requests to a server on a network that’s just waiting for the opportunity to do something. A Web browser is an example of a client accessing information from other Web sites that act as servers. Knowing the location of the user The iPhone Operating System (OS) and hardware allow a developer to determine the device’s current location, or even be notified when that location changes. As people move, it may make sense for your application to tailor itself to where the user is moment by moment. There are already iPhone applications that use location information to tell you where the nearest coffee house is, or even where your friends are. The MobileTravel411 application uses this information to tell you the nearest Tube stop and give you directions to your hotel. Tracking orientation and motion The iPhone contains three accelerometers — devices that detect changes in movement. Each device measures change along one of the primary axes in three-dimensional space. You can, for example, know when the user has turned the device from vertical to horizontal, and change the view from portrait to landscape if it makes for a better user experience. You can also determine other types of motion such as a sudden start or stop in movement (think of a car accident or fall), or the user shaking the device back and forth. It makes some way cool features easy to implement — for example, the Etch- A-Sketch® metaphor of shaking a device to reset it, and controlling a game by moving the iPhone like a controller. Tracking the action of the user’s fingers on the screen People use their fingers, rather than a mouse, to select and manipulate objects on the iPhone screen. The moves that do the work, called gestures, give the user a heightened sense of control and intimacy with the device. There is a set of standard gestures — taps, pinch-close and pinch-open, flicks, and drags — that are used in the applications supplied with the iPhone. 14 Part I: Getting Started I suggest strongly that you use only the standard gestures in your application. Even so, the iPhone’s gesture-recognition hardware and software allows you to go beyond standard gestures when appropriate. Because you can monitor the movement of each finger to detect gestures, you can create your own, but use that capability sparingly — only when it’s undoubtedly the right thing to do in your application. Playing audio and video The iPhone OS makes it easy to play and include audio and video in your application. You can play sound effects, or take advantage of the multichannel audio and mixing capabilities available to you. You can also play back many standard movie file formats, configure the aspect ratio, and can specify whether or not controls are displayed. This means your application can not only use the iPhone as a media player, but also use and control pre-rendered content. Let the games begin! Accessing the user’s contacts Your application can access the user’s contacts on the phone and display that information in a different way, or use it as information in your application. As a user of the MobileTravel411 application, for example, you could enter the name and address of your hotel, and the application would file it in your Contacts database. That way you have ready access to the hotel address — not only from MobileTravel411, but also from your phone and other applications. Then, when you arrive at Paddington Station, the application can retrieve the address from Contacts and display directions for you. Accessing the user’s pictures and camera As with Contacts, your application can also access the pictures stored on the user’s phone — and not only display them, but also to use or even modify them. The Photos application, for example, lets you add a photo to a contact, and there are several applications that enable you to edit your photos on the iPhone itself. You can also incorporate the standard system interface to actually use the camera as well. Embracing the limitations Along with all those features, however, the iPhone has some limitations. The key to successful applications — and to not making yourself too crazy — is to understand those limitations, live (and program) within them, and even learn to love them. (It can be done. Honest.) These constraints help you understand the kinds of applications that are right for this device. Often it’s likely that if you can’t do something (easily, anyway) because of the iPhone’s limitations, then maybe you shouldn’t. Chapter 1: Creating Killer iPhone Applications 15 So learn to live with and embrace some facts of iPhone life: ? The small screen. ? Users with fat fingers (me included). ? Limited computer power, memory, and battery life. The next sections can help get you closer to this state of enlightenment. Living with the small screen While the iPhone’s screen size and resolution allows you to deliver some amazing applications, it is still pretty small. Yet while the small screen limits what you can display on a single page, I have managed to do some mental jujutsu on myself to really think of it as a feature. When your user interface is simple and direct, the user can understand it more easily. With fewer items in a small display, users can find what they want more quickly. A small screen forces you to ruthlessly eliminate clutter and keep your text concise and to the point (the way you like your books, right?). Designing for fingers While the Multi-Touch interface is an iPhone feature, it brings with it limitations as well. First of all, fingers aren’t as precise as a mouse pointer, which makes some operations difficult (text selection, for example). User interface elements need to be large enough (Apple recommends that anything a user has to select or manipulate with a finger be a minimum of 44x44 pixels in size), and spaced far enough apart so that user fingers can find their way around the interface comfortably. You also can only do so much using fingers. There are definitely a lot fewer possibilities using fingers than the combination of multi-button mouse and keyboard. Because it’s so much easier to make a mistake using just fingers, you also need to ensure that you implement a robust — yet unobtrusive — undo mechanism. You don’t want to have your users confirm every action (it makes using the application tedious), but on the other hand, you don’t want your application to let anybody mistakenly delete a page without asking, “Are you sure this is what you really want to do?” Lost work is worse than tedious. Another issue around fingers is that the keyboard is not that finger-friendly. I admit it, using the iPhone keyboard is not up there on the list of things I really like about my iPhone. So instead of requiring the user to type some information, Apple suggests that you have a user select an item from a list. But on the other hand, the items in the list must be large enough to be easily selectable, which gets back to the first problem. 16 Part I: Getting Started But again, like the small screen, this limitation can inspire (ok may force) you to create a better application. To create a complete list of choices, for example, the application developer is forced to completely understand the context (and be creative about) what what the user is trying to accomplish. Having that depth of understanding then makes it possible to focus the application on the essential, eliminating what is unnecessary or distracting. It also serves to focus the user on the task at hand. Limited computer power, memory, and battery life As an application designer for the iPhone, you have several balancing acts to keep in mind: ? Although significant by the original Macintosh’s standards, the computer power and amount of memory on the iPhone is limited. ? Although access to the Internet can mitigate the power and memory limitations by storing data and (sometimes) offloading processing to a server, those operations eat up the battery faster. ? Although the power-management system in the iPhone OS conserves power by shutting down any hardware features that are not currently being used, a developer must manage the trade-off between all those busy features and shorter battery life. Any application that takes advantage of Internet access using Wi-Fi or the 3G network, core location, and a couple of accelerometers, is going to eat up the batteries. The iPhone OS is particularly unforgiving when it comes to memory usage. If you run out of memory, it will simply shut you down. This just goes to show that not all limitations can be exploited as “features.” A Compelling User Experience When you’ve got a handle on the possibilities and limitations of the iPhone, your imagination is free to soar to create a compelling user experience. Which reminds me: It’s worth considering what “compelling user experience” really means. For openers, a compelling user experience has to result from the interaction of several factors: ? Interesting, useful, plentiful content. ? Powerful, fast, versatile functionality. ? An intuitive, well-designed user interface. Chapter 1: Creating Killer iPhone Applications 17 Compelling content As I said earlier, there are a lot of different kinds of applications on the iPhone. What most of the really good ones have in common is focus. They address a well defined task that can be done within a time span that is appropriate for that task. If I need to look something up, I want it right now! If I am playing a game while waiting in line, I want it to be of short duration, or broken up into a series of short and entertaining steps. The application content itself then, especially for here-and-now applications, must be streamlined and focused on the fundamental pieces of the task. Although you can provide a near-infinity of details just to get a single task done, here’s a word to the wise: Don’t. You need to extract the essence of each task; focus on the details that really make a difference. Here’s an example: The other night, my wife and I were standing with some friends inside the lobby of a movie theater, trying to decide where to go to grab some dinner. It was cold (at least by California standards) but we wanted to walk to the restaurant from the theater. We had two iPhones going, switching from application to application, trying to get enough information to make a decision. None of the applications gave us what we really needed — restaurants ranked by distance and type, with reviews and directions. One of the applications was a great example of how to frustrate the user. It allowed you to select a restaurant by distance and cuisine. After you selected the distance, it gave you a list of cuisines. So far, so good. But the cuisine list was not context-based; when I tapped Ethiopian, all I got was a blank screen. Very annoying! I took it off my iPhone then and there — I don’t want an application that makes me work only to receive nothing in return. Your users won’t either. Every piece of a good application is not merely important to the task, but important to where you are in the task. For example, if I’m trying to decide how to get to central London from Heathrow, don’t give me detailed information about the Tube until I need it. That doesn’t mean your applications shouldn’t make connections that ought to be made. One aspect of a compelling user experience is that all the pieces of an application work together to tell a story. If the tasks in your application are completely unconnected, perhaps they should be separate applications. An application such as MobileTravel411 is aimed at people who may not know anything about their destination. If the application informs them that one reason to take the Heathrow Express is that it offers convenient Tube access on arrival in London, the users then have a bite-size bit of valuable information about how to get around London once they’re in the city. Save the train routes for when they’re in the station. 18 Part I: Getting Started By limiting the focus to a single task, it also enables you to leave behind some iPhone constraints, and the limitations of the iPhone can guide you to a better application design. Consistency with the user’s world Great applications are based on the way people — users — think and work. When you make your application a natural extension of the user’s world, it makes the application much easier and pleasant to use — and to learn. Your users already have a mental model that describes the task your software is enabling. The users also have their own mental models of how the device works. At the levels of both content and user interface, your application must be consistent with these models if you want to create a superb user experience (which in turn creates loyalty — to your application). The user interface in MobileTravel411 was based on how people divide up the experience of traveling. Here are typical categories: ? Foreign currency — how much it really costs and what’s the best way to convert money and buy things abroad. ? Getting to and from the airport with maximum efficiency and minimum hassle. ? Getting around a city, especially an unfamiliar one. ? Finding any special events happening while you’re in the city. ? Handling traveler’s tasks — such as making phone calls, tipping, or finding a bank or ATM — with aplomb. ? Checking the current weather and the forecast. ? Staying safe in unfamiliar territory — places you shouldn’t go, what to do if you get in trouble, and so on. This is only a partial list, of course. I get into this aspect of application design in more detail when I take you through the design of MobileTravel411. I suppose there are other ways to divide up the tasks, but anything much different would be ignoring the user’s mental model — which would mean the application wasn’t meeting some of the user’s expectations. It would be less pleasant to use because it would impose an unfamiliar way of looking at things instead of building on the knowledge and experiences those users already have. When possible, model your application’s objects and actions on objects and actions in the real world. For example, the iPhone has a set of iPod-style playback controls, tapping controls to make things happen, sliding on-off switches, and flicking through the data shown on Picker wheels. All of these are based on physical counterparts in the real world. Chapter 1: Creating Killer iPhone Applications 19 Your application’s text should be based on the target user. For example, if your user isn’t steeped in technical jargon, avoid it in the user interface. This does not mean that you have to “dumb down” the application. Here are some guidelines: ? If your application is targeted for a set of users who already use (and expect) a certain kind of specialized language, then sure, you can use the jargon in your application. Just do your homework first and make sure you use those terms right. For example, if your application is targeted at high-powered foreignexchange traders, your application might use pip (“price interest point” — the smallest amount that a price can move, as when a stock price advances by one cent). In fact, a foreign exchange trader expects to see price movement in pips, and not only can you, but you should use that term in your user interface. ? If your application requires that the user have a certain amount of specialized knowledge about a task in order to use your application, identify what that knowledge is up front. ? If the user is an ordinary person with generalized knowledge, use ordinary language. Gear your application to your user’s knowledge base. In effect, meet your users where they are; don’t expect them to come to you. The user interface – form following function Basing your application on how the user interacts and thinks about the world makes designing a great user interface easier. Don’t underestimate the effect of the user interface on the people who are trying to use it. A bad user interface can make even a great application painful to use. If users can’t quickly figure out how to use your application, or if the user interface is cluttered or obscure, they’re likely to move on and probably complain loudly about the application to anyone who will listen. Simplicity and ease of use are fundamental principles for all types of software, but in iPhone applications they are critical. Why? One word: multitasking. iPhone OS users are probably doing other things simultaneously while they use your application. The iPhone hardware and software is an outstanding example of form following function; the user interfaces of great applications follow that principle as well. In fact, even the iPhone’s limitations (expect for battery life) are a result 20 Part I: Getting Started of form following from the functional requirements of a mobile device user. Just think how the iPhone fulfills the following mobile device user wish list: ? Small footprint ? Thin ? Light weight ? Self contained — no need for an external keyboard or mouse ? Task oriented It’s a pretty safe bet that part of the appeal of the iPhone to many people — especially to non-technical users (like most of my friends) — is aesthetic: The device is sleek compact, and fun to use. But the aesthetics of an iPhone application aren’t just about how “beautiful” your application is on-screen. Eye candy is all well and good, but how well does your user interface match its function — that is, do its job? Consistency As with the Macintosh, users have a general sense of how applications work on the iPhone. (The Windows OS has always been a bit less user-friendly, if you ask a typical Mac user.) One of the early appeals of the Macintosh was how similarly all the applications worked. So Apple (no fools they) carried over this similarity into the iPhone as well. The resulting success story suggests the following word to the wise. . . . A compelling iPhone user experience usually requires familiar iPhone interface components offering standard functionality, such as searching and navigating hierarchical sets of data. Use the iPhone standard behavior, gestures, and metaphors in standard ways. For example, users tap a button to make a selection and flick or drag to scroll a long list. iPhone users understand these gestures because the built-in applications utilize them consistently. Fortunately, staying consistent is easy to do on the iPhone; the frameworks at your disposal have that behavior built in. This is not to say that you should never extend the interface, especially if you’re blazing new trails or creating a new game. For example, if you were creating a roulette wheel for the iPhone, why not use a circular gesture to spin the wheel, even if it isn’t a “standard” gesture? Making it obvious Although simplicity is a definite design principle, great applications are also easily understandable to the target user. If I’m designing a travel application, it has to be simple enough for even an inexperienced traveler to use. But if I’m designing an application for foreign-exchange trading, I don’t have to make it simple enough for someone with no trading experience to understand. ? The main function of a good application is immediately apparent and accessible to the users it’s intended for. Chapter 1: Creating Killer iPhone Applications 21 ? The standard interface components also give cues to the users. Users know, for example, to touch buttons and select items from table views (as in the contact application). ? You can’t assume that users are so excited about your application that they are willing to invest lots of time in figuring it out. Early Macintosh developers were aware of these principles. They knew that users expected that they could rip off the shrink-wrap, put a floppy disk in the machine (these were really early Macintosh developers), and do at least something productive immediately. The technology has changed since then; user attitudes, by and large, haven’t. Engaging the user While we’re on the subject of users, here’s another aspect of a compelling application: direct manipulation and immediate feedback. ? Direct manipulation makes people feel more in control. On the desktop, that meant a keyboard and mouse; on the iPhone, the Multi-Touch interface serves the same purpose. In fact, using fingers gives a user a more immediate sense of control; there’s no intermediary (such as a mouse) between the user and the object on-screen. To make this effect happen in your application, keep your on-screen objects visible while the user manipulates them, for example. ? Immediate feedback keeps the users engaged. Great applications respond to every user action with some visible feedback — such as highlighting list items briefly when users tap them. Because of the limitations imposed by using fingers, applications need to be very forgiving. For example, although the iPhone doesn’t pester the user to confirm every action, it also won’t let the user perform potentially destructive, non-recoverable actions (such as deleting all contacts or restarting a game) without asking, “Are you sure?” Your application should also allow the user to easily stop a task that’s taking too long to complete. Also: Notice how the iPhone uses animation to provide feedback. (I especially like the flipping transitions in the weather application when I touch the Info button.) But keep it simple; excessive or pointless animation interferes with the application flow, reduces performance, and can really annoy the user. Why Develop iPhone Applications? Because you can. Because it’s time. And because it’s fun. Developing my iPhone applications has been the most fun I’ve had in many years (don’t tell my wife!). Here’s what makes it so much fun (for me, anyway): 22 Part I: Getting Started ? iPhone apps are usually bite-size — small enough to get your head around. A single developer — or one with a partner and maybe some graphics support — can do them. You don’t need a 20-person project with endless procedures and processes and meetings to create something valuable. ? The applications are crisp and clean, focusing on what the user wants to do at a particular time and/or place. They’re simple but not simplistic. This makes application design (and subsequent implementation) much easier — and faster. ? The free iPhone Software Development Kit (SDK) makes development as easy as possible. I reveal its splendors to you throughout this book. If you can’t stand waiting, you could go on to Chapter 3, register as an iPhone developer, and download the SDK . . . but (fair warning) jumping the gun leads to extra hassle. It’s worth getting a handle on the ins and outs of iPhone application development beforehand. The iPhone has three other advantages that are important to you as a developer: ? The App Store. Apple will list your application in the App Store, and take care of credit-card processing, hosting, downloading, notifying users of updates, and all those things that most developers hate doing. Developers name their own prices for their creations; Apple gets 30% of the sales price, with the developer getting the rest. Apple has an iPhone developer program. To get your application into the store, you have to pay $99.00 join the program. But that’s it. There are none of the infamous “hidden charges” that you often encounter, especially when dealing with credit-card companies. I explain how to join the developer program in Chapter 3, and how to work with the App Store in Chapter 13. ? It’s a business tool. The iPhone has become an acceptable business tool, in part because it has tight security, as well as support for Microsoft Exchange and Office. This happy state of affairs expands the possible audience for your application. Examining the Possibilities Just as the iPhone can extend the reach of the user, the device possibilities and the development environment can extend your reach as a developer. Apple talks often about three different application styles: ? Productivity applications use and manipulate information. The MobileTravel411 application is an example. ? Utility applications perform simple, highly defined tasks. The weather application is an example. Chapter 1: Creating Killer iPhone Applications 23 ? Immersive applications are focused on delivering — and having the user interact with — content in a visually rich environment. A game is a typical example of an immersive application. Although these categories help you understand how Apple thinks about iPhone applications (at least publicly), don’t let them get in the way of your creativity. You have probably heard ad nauseam about stepping outside the box. But hold on to your lunch; the iPhone “box” isn’t even a box yet. So here’s a more extreme metaphor: Try diving into the abyss and coming up with something really new. The Sample Applications When I started writing this book, I decided that there was no way I was going to do what legions of computer-book authors have done from time immemorial. You know — some kind of insipid “Hello World” application. With a little more (although not much more) work, you can use the development environment to actually create something of value. In Figure 1-2, you can see the first application that I show you how to develop — the one I thought about after I lost my iPhone for the first time. I realized that if anyone found it and wanted to return it, well, returning it wouldn’t be easy. Sure, whoever found it could root around in my Contacts or Favorites and maybe call a few of them and ask if any of their friends had lost an iPhone. But to save them the work, I decided to create an application called ReturnMeTo, whose icon sat on the upper-left corner of the home screen and looked like something you would want to select if you had found this phone. It would show a phone number to call and create a very happy person at the receiving end of the call. Originally I thought I would simply create this application and then get on with the rest of the book. It turned out, however, that as I showed my friends the application, I got a lot of feedback and made some changes to it. I’ll include those changes as well — because they’ll give you insight to the iPhone application-development process. All my friends also told me that they’d love to have the application (hey, they’re my friends, after all). To pay them back for using them as a test group, I’ll be uploading it to the App store — I show you how to do the same with yours, in detail, in Chapter 13. After I go through developing ReturnMeTo, I take you through the design of MobileTravel411 in Chapter 14. Then I show you how to implement a subset of this application, iPhoneTravel411, which shows you how to use much of the “technology” that implements the functionality of the MobileTravel411 application. You’ll find out how to use table views (like the ones you see in the Contacts, iPod, Mail, and Settings applications that come with the 24 Part I: Getting Started iPhone), access data on the Web, go out to and return from Web sites while staying in your application, store data in files, include data with your application, allow users to set preferences, and even how to resume your application where the user last left off. I’ll even talk about localization and self-configuring controllers and models. (Don’t worry; by the time you get there, you’ll know exactly what that means.) Figure 1-2: ReturnMeTo — please! What’s Next I’m sure that you are raring to go now and just can’t wait to download the Software Development Kit (SDK) from the iPhone Developers Web site. That’s exactly what I did back in the day — and later was sorry that I didn’t spend more time up front understanding how applications work in the iPhone environment. So I ask you to be patient. In the next chapter I explain what goes on behind the screen, and then, I promise, it’s off to the races.