Detect key press in Actionscript 3

I have previously created a tutorial called Keyboard controls in AS3 where you learn how to move an object around the stage using the keyboard arrow keys. In this tutorial you will learn how to detect the other keyboard keys such as the letters, spacebar, enter key, shift key etc. You will also learn how to detect multiple key presses on the keyboard. Every character on the keyboard has a unique key code number which has been mapped specifically to a location on the keyboard. For example, the letter ‘a’ is the key code number 65.


Detect key press in Actionscript 3

Step 1

Open a new Flash AS3 file.
On the timeline select the first frame then open up the Actions panel and enter the following code.

//Adds event listener to the stage.
stage.addEventListener(KeyboardEvent.KEY_DOWN, detectKey);

//Traces the keycode, keylocation, shiftkey and altkey.
function detectKey(event:KeyboardEvent):void {
   trace("The keypress code is: " + event.keyCode);
   trace("The keyLocation is: " + event.keyLocation);
   trace("The shiftKey is: " + event.shiftKey);
   trace("The altKey is: " + event.altKey);
}

Step 2

Test your move clip Ctrl + Enter. Now if you don’t see any numbers being traced out, you need to disable the keyboard shortcuts. On the SWF menu bar click on Control > Disable Keyboard Shortcuts and then you should see the key code numbers being traced out. You will notice that the uppercase and lowercase characters produce the same key code.



You can also trace a message when certain characters on the keyboard have been pressed. In the example below only the ‘enter key’ and the ‘j’ key will display a message, the other key will display nothing.

if (event.keyCode==13) {
   trace("The enter key has been pressed");
}

if (event.keyCode==74) {
   trace("The j has been pressed");
}

The following example will display a message when the alt, control and shift key have been pressed.

if (event.shiftKey == true) {
trace("The Shift key has been pressed");
}
 
if (event.altKey== true) {
   trace("The Alt key has been pressed");
}
 
if (event.ctrlKey == true) {
   trace("The Ctrl key has been pressed");
}

You can also detect multiple key presses. This example will trace a message when the shift and ‘a’ keys have been pressed.

if (event.shiftKey== true && event.keyCode==65 ) {
   trace("The Shift key and a key has been pressed");
}