Interface Design Steps | Interface Design Issues

Interface Design Steps

• Introduction : Once interface analysis has been completed, all tasks (or objects and actions) required by the end user have been identified in detail and the interface design activity commences. 
• Interface design, like all software engineering design, is an iterative process. 
• Many different user interface design models have been proposed, all suggest some combination of the following steps : 
• Define interface objects and actions (operations). 
• Information developed during interface analysis, 
• Define events (user actions) 
• that will cause the state of the user interface to change. Model this behavior. 
• Depict (Represent) each interface state 
• It will actually look to the end-user. 
• Indicate how the user interprets the state of the system from information provided through the interface.

Interface Design Issues

• Introduction : Four common design issues almost always surface:
• (1) System response time,
• (2) User help facilities,
• (3) Error information handling,
• (4) Command labeling.
• It is far better to establish each as a design issue to be considered at the beginning of software design, when changes are easy and  costs are low.

(1) System response time,

• System response time is the primary complaint for many interactive applications.
• In general, system response time is measured from the point at which the user performs some control action (e.g., hits the return key or clicks a mouse) until the software responds with desired output or action.

(2) Help facilities, 

• Almost every user of an interactive, computer-based system requires help now and then.
• In some cases, a simple question addressed to a knowledgeable colleague can do the trick.
• In others, detailed research in a multivolume set of “user manuals” may be the only option.
• In most cases, however, modern software provides online help facilities that enable a user to get a question answered or resolve a problem without leaving the interface.

(3) Error Handling,

• Every error message or warning produced by an interactive system should have the following characteristics.
• The message should describe the problem in descriptive that the user can understand.
• The message should provide constructive advice for recovering from the error.
• The message should indicate any negative consequences of the error (e.g., potentially corrupted data files)
• The message should be accompanied by an audible or visual cue.
• The message should be “nonjudgmental.” That is, the wording should never place blame on the user.

(4) Menu and command labeling.

• The typed command was once the most common mode of interaction between user and system software and was commonly used for applications of every type.