Writing Mobile Code Essential Software Engineering for Building Mobile Applications [Electronic resources] نسخه متنی

Do Not Port Your Desktop Application! Think Devices!

Mobile device applications may share information sources and broad purpose with desktop applications, but beyond this the two classes of applications have little in common. Mobile applications should be designed for mobile devices from the start and not ported by removing pieces of a desktop application until it fits onto a device. For this reason, it is important to decide the scope of the mobile application and then design from the ground up.

Mobile Software Usage Patterns vs. Desktop Software

A myth that is worth dispelling is that mobile devices will replace personal computers; there seems to be no practical evidence to support this. As noted in the early chapters of this book, people use mobile devices in qualitatively different ways than they use desktop computers. To be successful in creating great mobile applications, think of mobile devices as augmenting existing software with new mobile behaviors as well as creating entirely new classes of software rather than replacing existing desktop or Web software.

Desktop and laptop computers do many things well, namely providing a rich random-access exploratory way of working with different sources of data. It is not uncommon during a session with a desktop or laptop computer to pull information together from several different sources and use applications in an ad hoc way. Think of working with a word processor, doing e-mail, shopping for airline tickets on the Web, or programming with a software development tool. All of these are rich exploratory activities that often involve long sessions at the computer. The user tends to work in an ad hoc way with different applications and data sources, often switching contexts between them. Good mobile device software, on the other hand, provides the user with a focused, task-centric ability to zoom in on needed information during short usage sessions. Think of the frustration of trying to look up an address on a badly designed mobile device address book. The user wants to quickly make a phone call. The last thing the user wants is to randomly explore data; 10 seconds is a frustratingly long time to fiddle with buttons and navigate user interface when trying to initiate a phone call. Mobile devices are about portability, about always being on, and about quick access to information and services in situations where a desktop or laptop computer is simply not the right paradigm.

When designing your mobile device application, it is important to specifically consider the usage patterns and specific circumstances of the people who are going to be using the software. Is the application going to be used in a delivery truck right after a package delivery is made? Will the application need to be simple enough to be used by people while walking down crowded streets or will people use it while sitting down in someone's office and looking up complex data? Is the application going to be used during a flight, where communications will need to be cached until connectivity is available? Is the application going to be part of a package, where the same person uses the desktop and mobile device software, or will the people using desktop computers and mobile devices be separate and united only by the data they work with? What is the level of experience the target user has with using other computers and applications? Will the user interface need to be simplified to take user inexperience into account? It is important to map out what the scenarios are for the mobile device part of your system and how the users will expect to use them. This will not only help you determine the right features and user interface for your mobile application but may also help you choose the right target hardware for your mobile solution. If your application requires a certain kind of user interface, this may have a strong effect on the hardware and form factors you choose for your application.