UIML: an appliance-independent XML user interface language

Today's Internet appliances feature user interface technologies almost unkn own a few years ago: touch screens, styli, handwriting and voice recognitio n, speech synthesis, tiny screens, and more. This richness creates problems . First, different appliances use different languages: WML for cell phones; SpeechML, JSML, and VoxML for voice enabled devices such as phones; HTML a nd XUL for desktop computers, and so on. Thus, developers must maintain mul tiple source code families to deploy interfaces to one information system o n multiple appliances. Second, user interfaces differ dramatically in compl exity (e.g, PC versus cell phone interfaces). Thus, developers must also ma nage interface content. Third, developers risk writing appliance-specific i nterfaces for an appliance that might not be on the market tomorrow. A solu tion is to build interfaces with a single, universal language free of assum ptions about appliances and interface technology. This paper introduces suc h a language, the User Interface Markup Language (UIML), an XML-compliant l anguage. UIML insulates the interface designer from the peculiarities of di fferent appliances through style sheets. A measure of the power of UIML is that it can replace hand-coding of Java AWT or Swing user interfaces. (C) 1 999 Published by Elsevier Science B.V. All rights reserved.