MIDP Style Guide for the Java 2 Platform, Micro Edition

1.3 Consumer-Product Domains

Specialization for particular activities is a strength of consumer products such as televisions and mobile phones. Even products that might be used for multiple activities have a fundamental purpose. For example, a mobile phone is primarily a communications device, even though it may also include a few games. Devices that are compelling and successful in the marketplace have the right focus and features.

The focus of a device (the tasks it performs and the setting in which it is used) identifies its domain. For example, the domain of a basic pager is information access. Its tasks are receiving and displaying phone numbers or short text messages. It is used in short sessions and can be carried to any location. The consumer must be able to retrieve information (a phone number or a short message) quickly.

A product's domain has implications for the UI design and the user experience. There are many domains for consumer products. This section covers three that are relevant to MIDP.

1.3.1 Information Access and Communication

Mobile phones typify consumer products in the information access and communication domain. For example, consider a consumer using a web-enabled phone to find a particular restaurant, call it, and make reservations. Figure 1.1 shows how a consumer might interact with an application to perform this task.

The information access and communication domain has the following characteristics.

• Products are used for:

  - Short periods at a time (a few seconds to five minutes)

  - Specific tasks

• Tasks:

  - Are usually structured and directed

  - Might be interrupted, but the interruptions are likely to be task relevant, such as getting a call while looking up a phone number

• Consumers:

  - Are likely to concentrate during their interactions

  - Approach the product with specific tasks or goals in mind

  - Are motivated to complete tasks and want quick, efficient, easy experiences

  - May be skeptical of the device's network connectivity

  - May doubt the device's ability to communicate properly at all times

The characteristics of this domain lead to the following design considerations.

Application Developers

Consider: Create UIs that provide efficient experiences. Task completion is important and time may be a critical factor. Consumers must be able to complete tasks quickly and efficiently.

Recommend: Make screens work together. For example, an application should not return information to the consumer in one screen only to have the consumer enter it again a few screens later. It is inefficient and frustrating for a consumer to enter information that the application should already have.

Recommend: Let the consumer know the outcome of an interaction that takes place across a network. It is obvious when some interactions have completed successfully. For example, when a browser requests a web page, the information exchange has obviously completed when the page is displayed. For other interactions, such as sending data to a remote location, the outcome might not be as obvious. Let consumers know that such data exchanges are progressing and when they are completed.

1.3.2 Business Functions

Products in the business functions domain help workers or operators perform very specific, job-related tasks. Examples include:

• Devices to help waiters take orders

• Applications to help assembly-line supervisors debug problems

• Devices to help delivery personnel plan routes and get customer signatures

These kinds of products can be thought of as vertical-market devices and applications because they target a specific task in a narrow field. Figure 1.2 shows an example application in this domain.

The business functions domain has the following characteristics:

• Products are used for job-related tasks, for which training costs can be an issue

• Tasks are such that interruptions are possible but are likely to be task relevant

• Tasks might be completed incrementally

• Consumers usually have domain knowledge specific to the application

The characteristics and design implications of the business functions domain are similar to those of the information access and communication domain; however, applications in this domain need to be efficient and predictable. (See "Information Access and Communication" on page 3.)

1.3.3 Entertainment

Playing a game on a mobile phone while standing in line at the grocery store exemplifies an interaction in the entertainment domain; for example, see Figure 1.3.

Consumer products used for entertainment, such as games on PDAs or gaming devices, share these characteristics:

• Products are used:

  - In comfortable, low-stress environments

  - For 10 to 30 minutes or more at a time

  - For less structured tasks

• Tasks are such that interruptions are possible

• Consumers:

  - Are likely to have varying levels of concentration and attention during their interactions

  - Approach the products with a relaxed attitude

  - Are more interested in a pleasant experience than in performing a specific task

Design considerations for the entertainment domain include the following.

Application Developers and MIDP Implementors

Recommend: Create UIs that interfere as little as possible with the content. For example, an application's controls should take up as little screen real estate as possible so that consumers can see more of the screen. Consumers will have various levels of concentration. Forcing consumers to concentrate on the UI will make their experience with the product less enjoyable.

Application Developers

Consider: Create entertainment UIs that provide a pleasant experience in preference to an efficient one. Task completion time in this domain is not a critical factor because the consumer is not under significant time pressure.

Efficiency is a positive attribute, but in the entertainment domain, a pleasant and compelling experience is as important as efficiency. Predictability, however, is more important than efficiency.

Consider: Devote as much I/O bandwidth as possible to seeing, hearing, and interacting with the entertainment. The interaction of the consumer and the game is the product's most important feature.