ActionScript: The Definitive Guide

Name

Key Object — determine the state of keys on the keyboard

Availability

Flash 5

Synopsis

Key.property

				Key.methodName( )

Properties

Table 20.7 lists the properties of the Key object.

Table 20-7. Key Object Keycode Properties

Property	Equivalent Keycode	Property	Equivalent Keycode
BACKSPACE	8	INSERT	45
CAPSLOCK	20	LEFT	37
CONTROL	17	PGDN	34
DELETEKEY	46	PGUP	33
DOWN	40	RIGHT	39
END	35	SHIFT	16
ENTER	13	SPACE	32
ESCAPE	27	TAB	9
HOME	36	UP	38

Methods

getAscii( )

Returns the ASCII value of the last key pressed

getCode( )

Returns the keycode of the last key pressed

isDown( )

Checks if a specific key is currently depressed

isToggled( )

Checks if the Num Lock, Caps Lock, or Scroll Lock keys are activated

Description

The Key object is used to determine which keys are currently depressed and which key was last depressed. We can use it to build interfaces controlled by the keyboard, such as a game with a spaceship moved via the arrow keys.

Because not all keyboards are identical, keyboard-controlled interfaces can sometimes be tricky to create. By choosing our scripting tools correctly, however, we can ensure that all users have the same experience.

There are two general approaches to detecting keyboard commands:

• We may check if a key is currently depressed via the isDown( ) method. This is recommended for cases in which keyboard input is constantly required, such as in video games.

• We may check which key was last depressed using the getCode( ...