开发mobile要知道的六件事情（Six things you need to know about developing mobile applications）

Bert Latamore

August 02, 2007 (Computerworld) Mobile applications are moving beyond e-mail on cell phones to real functionality linked back to applications on corporate servers.

Mobile devices are therefore becoming intelligent front ends for corporate applications, capable of capturing and storing information locally, and then exchanging that information with the company when connectivity is available.

No. 1: Not just toys anymore

So the first thing corporate IT needs to realize about this new trend is that handhelds are no longer just executive toys -- a way to stay in touch with the office from the beach. They are real productivity tools, and the action, says Steve McCorry, technical director for PSM Mobility Ltd. in London, is blue-collar field service-type applications.

"The first thing service people do every morning is come into the office to pick up their work orders," McCorry says. "Then at the end of the day, they go back to the office to turn in the completed sheets of paper. Well, all that time they spend driving to and from the office is time they aren't being productive."

PSM Mobility is a reseller of handhelds, mainly based on ruggedized Motorola (formerly Symbol) Windows Mobile devices, to corporations for field support. It started selling hardware and moved into customized application development to support customer needs.

What its customers often want is a product for digitizing and automating the interchange of those work orders between central dispatch and field personnel so that they can start their day at their first assignment and finish it at their last one. The product is typically a ruggedized handheld device that can connect back to the corporate dispatching application over a secure Internet connection. And this has the extra benefit that a dispatcher can reroute service personnel during the day to respond to emergencies. That increase in productivity alone can easily justify the purchase of the ruggedized handhelds.

No. 2: Don't repeat mistakes of PC revolution

The second thing to recognize is that IT doesn't want to repeat the mistakes of the PC revolution in handhelds. Specifically, it doesn't want these devices to become tiny islands of automation with minimal connectivity. Twenty-five years after IBM's first PC, many organizations are still struggling to get vital corporate data out of spreadsheets and onto networked applications.

But simple browser-based access to applications on corporate servers isn't sufficient partly because even with multiband (Wi-Fi and cellular) devices, IT can't guarantee universal connectivity at every site, which a browser-based application demands. The device needs the ability to store and, to an extent, process data locally for those times when connections fail and the smarts to transmit that data when connectivity is restored.

Also, neither the stand-alone nor the browser-based approach provides the flexibility that the field environment often demands. And the third thing that IT needs to know about mobile devices, says McCorry, is to keep your options open. And the key to that and to simpler, faster custom application development on handhelds, he says, is middleware, and specifically the Agentry platform from Syclo LLC.

For example, one of PSM Mobility's customers installed thousands of PCs on corporate desktops. It wanted a mobile asset management application to track the hardware and software it installed, both for its own records and those of its customers. "The challenge was that they work with a wide variety of organizations, from large merchant banks who want a precise accounting of assets, including disposal of replaced PCs, to some pretty laid-back organizations."

As a result, the data capture and reporting parameters are different for each client, and sometimes a customer may change its data requirements in the middle of an engagement. "Handheld applications tend to be pretty inflexible, so accommodating these changes would be difficult on a handheld-based solution," says McCorry. PCM's solution was to use Agentry to build an easily customizable front-end form on the handheld linked over the network to a database back end that is easily customized to the need of individual clients.

Another client provides office management and janitorial services to office buildings. It initially came to PCM for a mobile system for its field maintenance teams to use to track their activities for billing. "They had a customer who complained that their people weren't spending enough time at his location," McCorry says. "So the problem became how do you prove where someone was at a given date and time." The answer was to use a handheld with a built-in GPS, in this case the Symbol MC70. "Syclo has a neat tool that lets you capture time-stamped GPS coordinates as part of the work orders to prove they did visit the sites when they were scheduled to."

No. 3: Handhelds have special capabilities

This illustrates a third point. Just as PCs have their own set of applications that are different from those on servers, so handhelds represent a new class of computing with their own unique set of capabilities. In large part, these are location based, either capturing records as events occur or providing information about the immediate vicinity. For example, handhelds can be used to capture information about the location of a work group at specific times, what they did -- including bar code scans of equipment installed or parts replaced -- and signatures of customers verifying work order completion.

No. 4: Different physical needs in the field

The fourth thing IT needs to know, says McCorry, is that field service workers have different physical needs in a handheld from executives. Tiny, sleek and fragile don't make it with people who spend their day with large, heavy tools. But equally they need something they can carry on a tool belt or pocket. They don't have free hands for a tablet or portable computer. "The MC70 is a ideal form factor for mobile, blue-collar workers," McCorry says.

No. 5: Intelligent devices result in call for more apps

Once they have intelligent devices, they will quickly start asking for more applications. Field service personnel often need to track expenses and mileage, for example, so why not an application that lets them capture that data as it happens and report that back directly into the accounting applications at headquarters?

They also typically have to carry a library of service manuals. If those can be digitized and put either into the device's memory or an SD card, the company can eliminate the need for printing and distributing paper manuals and automate updating through downloads to ensure everyone has the most recent versions. And the service workers will always have the information they need at hand, rather than in the trunk or left at home, without having to carry a heavy manual with them as well as tools and spare parts. So when selecting a device to standardize on, think about expandability.

No. 6: Battery life is vital

Finally, battery life is vital for a device intended for field use that will not be near a recharger all day. Obviously, the most capable device does little good if its battery dies halfway through the day, which is another reason tablets -- which because of their large screens, tend to have a three-to-four hour battery life -- are often not a good choice for blue-collar field applications. "Battery life has improved over the years," McCorry says, "but the number of peripherals that need power has grown right along with that."

The key, he says, is to get into the low-level device management software and optimize the device for maximum battery life. With Wi-Fi, Bluetooth, cellular and infrared running constantly, the battery may only last three hours. But by adjusting the management functions to turn off those power-draining peripherals except when they are needed, battery life can be extended to comfortably cover the full workday. For example, have the Wi-Fi and cellular only come on when a work order is completed and ready to send, only activate the infrared when the bar-code software is opened, etc.

Overall handhelds are becoming mainstream, the front ends of the new service-level architecture applications, extending machine intelligence and the efficiencies it brings to operations that have never known computers before. Today, this can offer competitive advantage to organizations that harness them first to increase efficiency and drive out costs. Tomorrow inevitably, they will become a competitive necessity, particularly in industries with large field staffs, and late adopters run the risk of coming out behind in the competitive race.

Bert Latamore is a journalist with 10 years' experience in daily newspapers and 25 in the computer industry. He has written for several computer industry and consumer publications. He lives in Linden, Va., with his wife, two parrots and a cat