Discovering Flex

Adobe Flex is a new medium specifically created for designing and developing rich Internet applications, or RIAs. RIAs are a new breed of applications that break out of the constraints of traditional web and desktop environments to provide a more fluid, information-focused user experience. Flex makes it much easier to create these experiences, but it requires application designers and developers to think differently about the application design problem than they did when creating traditional web and desktop applications.

If you’re reading this document, chances are you’re getting ready to embark on a journey into the world of Flex application design. Perhaps you’re an interface or interaction designer who knows application design inside and out. Perhaps you’re a UI-savvy developer who builds applications that don’t just work, but work well. Or perhaps you’re a manager or business analyst who leads application design projects. Whether you come from the world of the web, the desktop, or are already experienced with Flex, this series offers a solid foundation of knowledge to apply and extend as you design and develop your next great Flex application.

Flex applications have much in common with their web and desktop predecessors, but they also require a somewhat unique approach to design. This section covers:

• How Flex differs from other technology mediums.
• Why Flex is an ideal technology for crafting rich Internet applications.
• Why Flex gives you more freedom, yet requires you to design in a slightly different way than you did for HTML or desktop technologies.

The Flex rich Internet application

From the very beginning, we designed Flex to be the best platform available for designing and building RIAs. Flex RIAs enable designers and developers to build applications that break out of the old constraints of the web and the desktop to deliver experiences that are more useful, usable, and desirable for their intended users. However, Flex also introduces new design challenges to overcome and new user expectations to meet. These challenges and opportunities are caused by two aspects of well-designed Flex RIAs:

They blend web and desktop idioms and thus must satisfy user expectations for both mediums. They open up new design possibilities through their ability to use motion in applications, render content in novel ways, and perform many computations and screen updates directly on the user’s computer while still having access to all the information services of the Internet.

Flex applications blend the web and the desktop by borrowing the best from both mediums. Most Flex applications appear on a website, usually alongside traditional HTML content and applications. Users of these Flex applications have certain expectations of “web-ness” that goes along with the environment: They expect their browser’s back button to return them to the location they’d been to before. They expect to bookmark sections of your application and to add hyperlinks to other web pages that connect them directly to that section. They expect the visual appearance of your application to seamlessly match the branding of the rest of your website. Lastly, they expect to access your application anywhere, on any computer, regardless of their browser or operating system software.

Likewise, Flex also brings the feel and to some extent the look of the major desktop operating systems to the web. Flex provides out-of-the-box implementations of advanced desktop controls such as tabs, sliders, trees, and data grids as well as advanced desktop idioms such as drag and drop, direct selection, and in-place validation. Because these controls and idioms are readily available and consistently implemented, users come to expect a richness of interaction that they might not from a traditional website.

Flex opens up new design possibilities by enhancing standard web browsers with the Adobe Flash technology on which Flex is built. This technology is now available in two compatible runtime environments: Adobe Flash Player, a browser plug-in that is installed on 98% of the world’s internet-connected PCs; and Adobe AIR, a runtime that allows Flex applications to exist on the user’s desktop outside the confines of a web browser. Both runtimes provide a set of powerful, time-tested tools that open up new possibilities for web and desktop application design. These tools include:

Powerful drawing and media APIs for using vector graphics, bitmap graphics, and high-quality video to build rich information displays for your application. Popular examples include the stock charts on Google Finance and the interactive video player on YouTube

Built-in support for motion and effects effects that creates new ways to guide users and provide meaningful feedback.

A modern code execution engine that is powerful enough to enable hard-core developers to build any application behavior they wish, yet has its roots in a simple scripting language that empowers even non-programmers to express their ideas in code. This engine enables designers and developers to make use of the user’s computer, rather than the server, for many processing tasks involving validating data, safeguarding information, and caching results to reduce latency