Eng:When () Key Pressed (block)

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When () Key Pressed
Category	Event
Type	Hat

The When () Key Pressed block is an Events block and a Hat block. Scripts placed underneath this block will activate when the specified key is pressed.

The keys that can be sensed with this block include the entire English alphabet ( a b c etc.), the number keys ( 0 1 2 etc.), the arrow keys ( ← ↑ → ↓ ), and the space key. After an update, this block now includes an any option, which allows one to press any key to operate the block.

In the Experimental Viewer, the ↵ Enter key (or return key on Macs) could also be sensed.

The block will act similarly to typing text in a text box. There will be a delay between when the block first executes and the second time, but after that, there will be no delay until the key is released.

Example Uses

This block is used to get input from the player, for a variety of uses.

Some common uses include:

• Controlling an object

when [space v] key pressed
broadcast [Fire! v]
repeat (5)
 change y by (5)

• Typing on a word processor

when [a v] key pressed
switch to costume [a v]
stamp
change x by (20)

• Starting animations

when [space v] key pressed
broadcast [Animation starts! v]
play sound [Intro v]

• Moving around a map

when [up arrow v] key pressed
change y by (15)

Note:

Because of the built in delay, the <key [ v] pressed?> Boolean is often used for movement, as it will execute its script more rapidly and make movement smoother.

Workaround

Main article: List of Block Workarounds

This block can be partially replicated with the following code:

when flag clicked
forever
 if <key [wanted key v] pressed?>
 . . .
end

Note:

This workaround is not exact, as the hat block will break off in the middle of a script, but the workaround will not. The built-in delay in the hat block (if you hold down the key, there will be a slight pause, followed by a shorter pause) is not inherent in the workaround. Also, the hat block does not require the green flag to be pressed.

A more precise workaround:

when gf clicked
forever 
if <key [key v] pressed?> then
broadcast [ready v]

when I receive [ready v]
. . .

See Also

• Key () Pressed?