KeyEventKEYCODE

KeyEvent.KEYCODE is a collection of integer constants defined in the Android SDK within the android.view.KeyEvent class. Each constant represents a specific key code used by the input system to identify key presses and releases from physical keyboards, soft keyboards, or other input devices. These codes are delivered to applications through input events such as onKeyDown, onKeyUp, or onKeyMultiple, typically accessible via event.getKeyCode().

The KEYCODE set covers multiple categories, including alphanumeric keys (for example, KEYCODE_A through KEYCODE_Z and KEYCODE_0 through KEYCODE_9), navigation keys (such as DPAD_UP, DPAD_DOWN, DPAD_LEFT, DPAD_RIGHT, ENTER, CENTER, BACK, MENU, HOME), and functional or system keys (such as BACK, HOME, MENU, SEARCH, POWER, VOLUME_UP and VOLUME_DOWN, CAMERA, ENTER, SPACE, DEL). It also includes keys used by devices with hardware controls or external keyboards, as appropriate for the device and input method.

Because key codes can vary by device, input method, and keyboard layout, some codes may not be implemented on all devices or may map to different physical keys. Developers should handle unknown codes gracefully and can rely on getUnicodeChar to obtain the character representation for keys that produce printable input.

Example usage: if (event.getKeyCode() == KeyEvent.KEYCODE_A) { … } demonstrates handling a specific alphanumeric key. For complete coverage, refer to the official Android documentation for the full list of KEYCODE constants and their meanings.