Key Events

A device must support key events for both game actions and the keys of an ITU-T standard telephone keypad. Game actions are device-independent key events representing up, down, left, right, select/fire, A, B, C, and D. The ITU-T standard telephone keypad corresponds to key events for the digits 0 to 9, and the symbols pound (#) and star (*).

MIDP Implementors

Strongly Recommend: Decide and publish how you will map key events onto the device.

Consider: Consider game actions the default input mechanism for canvases and make them consistent with the device. For example, Sun's MIDP for Palm OS maps the left, right, up, down, and select/fire keys to those commonly used by native game apps for these functions, as shown in Screenshot.

Screenshot Mapping of Common Game Actions on a PDA

Key-event mappings for the phone keypad might be more natural on one device than on another. For example, they map directly onto a phone, but not onto a device with a QWERTY keyboard or a device with no alphanumeric keypad. A device with a QWERTY keyboard could map the digit keys to the row of numbers above the keyboard, as shown in Screenshot.

Screenshot Mapping the Digit Key Events onto a QWERTY Keyboard

A device with no alphanumeric keypad, such as a PDA with touch input, could support the phone keypad by creating a touch-sensitive onscreen representation that the user can display on the screen, as shown in Screenshot.

Screenshot Onscreen Representation of a Phone Keypad on a PDA

app Developers

Strongly Recommend: Use game actions instead of the phone keypad whenever possible because game actions are more usable across devices. For example, consumers that must show and use the keypad shown in Screenshot report in usability testing that it feels awkward to use. It is not a Palm OS standard and shares the screen with the app, decreasing the app's display size.

The game actions up, down, left, right, and select/fire are familiar to many consumers because they are commonly used by games. There are no standard uses for the game actions A, B, C, and D, however. (They might be seen as roughly equivalent to the extra keys on game machines, sometimes labeled A, B, L, and R. These keys too are used as the game finds necessary.)

Consider: Publish your use of game actions or the phone keypad keys for consumers. Provide Help screens for Canvas screens, especially when you use the game actions A, B, C, and D. Consumers have no way of knowing from prior experience what A, B, C, and D do. Explaining the functions of the game actions or phone keypad lets consumers enjoy the app rather than getting frustrated figuring out how to operate it.