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SECONDARY LABELS, ALSO LIKE MODE SWITCHES>...

Problem

Functions on the device, and in the interface, are controlled by a series of keys arrayed around the periphery of the device. Users must be able to understand, learn and control their behavior.

Solution

Outside of Keyboards & Keypads and Directional Entry controls, practically all mobile devices have numerous additional keys. Regardless of their function, all must comply with some basic behavioral standards in order to be useful, usable and valuable to the user.

Variations

There are two basic types of hardware keys, based on their effect.

  • Hardware -- The key affect is to device hardware. Any on-screen, interactive display is incidental to the function. These are functions like volume, and radio toggles.

  • Interaction -- The key affect is only to interactive, software driven elements, generally resulting in a principle, unmistakable interaction. Back, search or camera keys are representative of this type.

In either case, the attributes and behaviors discussed in this pattern are applied in the same manner.

Interaction Details

The use of any hardware key must have an immediate, noticeable response, regardless of the type of function being performed. This applies even if the action takes some time to take effect, such as time to load the camera application.

There should always be a visible effect. Generally, this should be an on-screen display of some sort. If the primary effect is either not an interactive element, or cannot be launched within about 1/10th of second, and secondary display must be used. Though many options are available, some frequently-used variations are:

  • Pop-up dialogue, sometimes a variation which is for display only, has no opaque bounding box or background field, and cannot be interacted with.

  • Annunicator or other notification indication. An icon can be added, or change in an obvious manner.
  • Pre-launch the application. If camera hardware takes a few seconds to load, the camera application can still begin launching immediately, and open in a state that indicates this delay.

Pop-Ups will generally disappear after a few seconds. Annunicators may need to remain in place, to indicate the change of state permanently, such as enabling Bluetooth features, which displays the Bluetooth icon in the Annunicator Row.

Direct responses should also be used when technically feasible. If individual-key backlight is available, the backlight should dim momentarily during keypress. Rarely, this may be used successfully as an indicator with all key backlighting changing based on certain keypresses.

Haptic or audio responses are also valuable as a way for the user to confirm the key has been activated, or for multi-step keys (such as volume) to give a better sense of the number of steps entered. Subtle clicks, whether through vibration or the speaker, can serve this need.

PRESS-AND-HOLD... COPY FROM MODE SWITCHES OR REFER...

Presentation Details

The key must be unambiguously labeled with the function. Volume keys may get a pass as they are expected, so any single key pair may be understood to be volume controls. However, the difference between the camera and power buttons -- for example -- should be made clear by labels.

Labels should be visible in all conditions. See the Mode Switches pattern for additional details on this, and especially for risks of backlight under certain lighting conditions.

labels and descriptions for on-screen effects such as notification icons should comply with the hardware label to draw a clear parallel between the two.

Key position should considered carefully. Keys should meet established best practice whenever possible. Camera buttons are very often arranged like a shutter, so are at the right side of the top edge when in conventional (landscape) orientation.

On-screen behaviors and their keys should be adjacent to each other whenever possible. Softkeys, for example, must be near the bottom edge of the screen, and aligned near the left and right edges. If the position of more obscure keys is known to the software, it may be pointed to as an aide to the user, either routinely or during first-run tutorials or help topics.

SECONDARY LABELS, ALSO LIKE MODE SWITCHES>...

Antipatterns

Do not cast labels into keys without highlighting with color and/or providing a backlight. Impressed keys labels are unreadable under all but the best lighting conditions, and will not be understandable by the user.

Do not make up new symbols to denote key functions. Use common, universally-recognized icons or other labels.

Do not attempt to use lines or other guides to make up for softkeys far-removed from the screen. If this cannot be surmounted, users will eventually learn it, but guides do not tend to help.

Examples

Other Hardware Keys (last edited 2011-07-31 23:13:42 by shoobe01)