Flex Article

Designing for Flex – Part 4: Merging the web and the desktop

Flex accessibility

Accessibility for disabled users is an important concern for most web and desktop applications. In many countries, any application created for the government must meet certain accessibility requirements by law. Even those applications that have no legal obligations may not wish to alienate users with disabilities.

Although it is not strictly a web/desktop issue, Flex accessibility contains elements of both desktop and web approaches. I will discuss how to use these mechanisms to support disabled users here.

When someone mentions accessibility, most designers and developers think of support for screen readers and keyboard-only navigation. Flex supports both of these features. For the standard component set, this requires little extra work so long as you compile your application with accessibility support enabled (it is not enabled by default). Usually you only need to set the tab order so that the tab key moves between the controls in a logical order. This is important even to non-disabled users, as many users frequently use the tab key to move between form fields while entering data.

Figure 10. Diagram showing the expected tab ordering through a hypothetical order form. For users from western nations, tab order should generally move left-to-right, top-to-bottom within a section. Ensure that you tab through all the controls of one section before jumping to the next.

Most disabled users, however, are not blind and do not require the use of a screen reader. Most are low-vision users; they can see the screen but have difficulty reading small text or distinguishing elements with low contrast. Many users also lack fine motor skills and may have difficulty using small controls. Do not overlook the importance of providing colors and font sizes that are legible to low-vision users and control sizes that are easy to manipulate. One option is to simply provide high-contrast colors and sufficiently large fonts and controls in your application to begin with. This is the best option if a large percentage of your users will be low-vision. For applications with only a small percentage of low-vision users, however, this may make the design less desirable to users with normal vision. Instead, use Flex’s style sheets to provide alternate versions of the application design which increase the font size, the size of controls, and the contrast of colors.

Figure 11. Adobe.com supports type size adjustment for low-vision users (although it could, perhaps, support it more gracefully).

Flash has a bad reputation for lacking support for accessibility, but this is no longer true. With no more effort than is typically required for an HTML web application, you can make Flex applications equally accessible to disabled users.

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