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.Notice that the data is still readable and the user won t have to guess about theformatting.Of course, this is still a less than perfect solution, since the data does appear ontwo lines.It s important to keep every application element on a single screen if possible.The exampleapplication does this by sacrificing application data display space.The user can scrollthrough the data in the Result values field without moving other screen elements around.The stylus provided with a PDA doesn t lend itself to mouse-like movement.Make sure you consider XHTML for complex applications with many elements.It allows youto display your application in segments with relative ease.Other options include using theHandheld Device Markup Language (HDML) (http://www.w3.org/TR/NOTE-Submission-HDML-spec.html) or Wireless Markup Language (WML) (http://www.oasis-open.org/cover/wap-wml.html).Both of these technologies use the concept of cards anddecks to break information up into easily managed pieces.Of course, the PDA you use hasto provide support for these standards before you can use the tags within a document.Aswith XHTML, using either HDML or WML will prevent your page from appearing properly ona desktop machine.Using ColorDevelopers have gotten used to seeing colors on their applications.Color dresses up a drabdisplay and makes the application more fun to use.In addition, using color presents cues tothe user.For example, many users associate green with a good condition and red withsomething bad.In short, most applications rely heavily on color today, and with good reason.Depending on the PDA you use, you may not have any color at all.For example, many Palmmodels present the world in shades of gray.Even if a PDA does provide color support akinto the Pocket PC, the developer still has to use color carefully.The problem for PDA users is that the screen is already small.If they get into an area withbright sunlight, seeing the screen might become impossible, especially if it s filled with colorsthat don t work well in such an environment.Notice that the PDA screenshots in this chapterare mainly black and white.The actual screens contain some color for the icons, but that s about it.Since these applications don t need color to present the information they canprovide, it s possible to rely on a black and white image.Using color to display icons or to convey a message is still a good idea, even in the world ofthe PDA.For example, a red icon could signal danger or tell the user to wait without using upscreen real estate for words.Of course, you need to explain the meaning of the colorchanges within a manual or help file (preferably both).Pointer PointersMost PDA users rely on a pointer to do all of their work.Sure, a few PDAs do offer akeyboard and mouse as separate items, but most of these offerings are bulky and difficult touse.Pointer use is one of the reasons that you want to keep your application on one screenor use multiple screens when necessary.Scrolling on a PDA screen is less than intuitive andrequires some level of skill to master.SOAP applications that you move from the desktop to the PDA will require somemodification for screen size in many cases.While you re working on the screen, it might be agood time to add some pointer friendly features as well.For example, try to make as manytasks a single pointer option as possible.The user should be able to point to what theywant and allow the PDA to complete it for them.You can also build intelligence into the application.A SOAP application normally has a directconnection to the server.You can use some of the server s processing power to make thingseasier on the user.Most PDAs already include predictive logic as part of their setup.Forexample, as you write something, the PDA tries to guess the entire word.When it guessesthe correct word, you can click on it and save some writing time.The same principle worksfor other activities as well.For example, a SOAP application could automatically display adata screen that the user needs most often, rather than force the user to dig through severalscreens to find it.Pointer-friendly programs also make tasks yes or no propositions.Again, this allows theuser to accomplish the task with a single click, rather than having to write something down.The point is to make the PDA as efficient as possible so the user doesn t get frustrated tryingto do something simple.Understanding PDA Security IssuesMany network administrators view the PDA with more than a little suspicion, and for goodreason.The media has painted the PDA as a device that is so open that anyone can accessit at any time, so that smart users keep all of their sensitive data on the company computerand just place lists of tasks on their PDA.Of course, such a view defeats the entire purposeof having a PDA in the first place.A PDA should be an extension of your workplace not ahindrance to avoid.Many of the security concerns surrounding PDAs today are based on a perception thatthey re all wireless devices.Many PDAs use network or modem connections, not wirelessconnections.The PDAs that do provide wireless access tend to err on the side of safetywhenever possible.Vendors realize that wireless access is both a blessing and curse formany companies.However, the wireless issue probably isn t much of a concern for theSOAP developer.Count on many of your users to rely on modem or direct network interfacecard (NIC) connections.For example, the Pocket PC provides a slot that will accommodatean Ethernet card that provides a direct network connection. One of the biggest security issues for all PDA users is data storage.There are actually twothreats to consider.The first is that someone could access sensitive data if they stole yourPDA (or, at least, borrowed it for a while).Wireless or not, the person who has the PDA alsohas access to the data it contains.The second threat is data loss.Many PDAs lose all oftheir information once the main battery is exhausted.(Some PDAs provide a backup batterythat retains the contents of memory until the user replaces or recharges the main battery
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