User Input

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Obviously, not every program interacts with a user in the same manner. For instance, a paint program such as Adobe's PhotoShop is very much mouse-oriented; you perform the majority of the functions in PhotoShop by using the mouse or some other pointing device. The idea of allowing a user to perform each and every function in PhotoShop using only the keyboard is a pipe dream for sure, but the product's developers have provided ways for users to use the keyboard to accomplish certain tasks . Although it's best to accommodate both keyboard and mouse usersyes, these are often separate campsthe nature of an application itself might make this extremely difficult.

At the opposite end of the spectrum are data entry applications. Data entry people are primarily keyboard people. If you really want to make one of these folks mad, insert a mouse-only task in the middle of a data entry process. (Remember, even though your program is a shining jewel to you, it's just a tool to the user.) Interrupting the user's work flow this way complicates the process for the user by adding a change of work mode. Because that change of mode is likely to be perceived as unnecessary by the user, it quickly becomes tedious and frustrating with repetition. So, when considering the interaction between the user and your program, be mindful of your target market. Create a profile of the type of person you expect to run your program, and carefully consider how that person works.

Most applications fall somewhere between the mouse extreme and the keyboard extreme. Microsoft Visual Basic, for example, requires you to be proficient with both the mouse and the keyboard. You can't write code with the mouse, but try adding controls to a form, moving and aligning them, and setting properties to create a functional and attractive interface by using only the keyboard! Because in most cases a user must work with both the mouse and the keyboard, it's important to make the transitions between the two input devices as smooth as possible. Furthermore, it's vitally important that you provide mouse capability and keyboard capability whenever possible. When a function supports both the mouse and the keyboard, it has what I call interactive duality . Interactive duality ensures that users will be able to use your program in the manner that suits their needs best.

Say you're typing some code in the Visual Basic code editor and you now want to test your changes by running the project. What do you do? Because your hands are already positioned on the keyboard, the most efficient method is pressing F5. On the other hand, say you're dragging a control around on a form with the mouse, trying to find that perfect spot for the control. You have the control where you want it and now want to run the project to see how it looks in run mode. Of course, the most efficient method in this case is clicking the Run button on the toolbar. You're already using the mouse, so this is quick and easy. Whenever you have to switch between the keyboard and the mouse, a pause occurs in your work process as your mind switches gears and you reposition your hands. However slight that pause might be, it's a distraction that's often avoidable because most functions can be created with interactive duality.

A program's interface is both a barrier and a bridge. This chapter teaches you how to make interfaces that let users more easily meld with your program. A good interface lets users do their jobs without having to think about the mechanics of the process. This undoubtedly creates more satisfied users, which helps you enjoy reduced support costs, an increase in the number of users that purchase upgrades, and better word-of-mouth advertising.