Notification that a key transitioned from "up" to "down".

Notification that a key was pressed. This does not necessarily correspond to a character depending on the key and language. Use KEYEVENT_CHAR for character input.

Notification that a key was released.

Notification that a character was typed. Use this for text input. Key down events may generate 0, 1, or more than one character event depending on the key, locale, and operating system.