konami code in flex

Question

What would be the best way to implement the konami code into a flex application?

I want to create a component to add it on all my proyects, just for fun.

thanks

UPDATE: I made a simple component, thanks to ZaBlanc

<?xml version="1.0" encoding="utf-8"?>
<mx:UIComponent xmlns:mx="http://www.adobe.com/2006/mxml" creationComplete="init()">
    <mx:Metadata>
     [Event(name="success", type="flash.events.Event")]
    </mx:Metadata>
    <mx:Script>
     <![CDATA[

      // up-up-down-down-left-right-left-right-B-A
      public static const KONAMI_CODE:String = "UUDDLRLRBA";

      // signature
      private var signatureKeySequence:String = "";

      private function init():void{
       systemManager.stage.addEventListener(KeyboardEvent.KEY_DOWN, onKeyDown);
      }

      private function onKeyDown(event:KeyboardEvent):void{
       var keyCode:int = event.keyCode;

          switch (keyCode) {
              case Keyboard.UP:
                  signatureKeySequence += "U";
                  break;

              case Keyboard.DOWN:
                  signatureKeySequence += "D";
                  break;

              case Keyboard.LEFT:
                  signatureKeySequence += "L";
                  break;

              case Keyboard.RIGHT:
                  signatureKeySequence += "R";
                  break;

              case 66: //Keyboard.B only for AIR :/
                  signatureKeySequence += "B";
                  break;

              case 65: //Keyboard.A only for AIR too :(
                  signatureKeySequence += "A";
                  break;

              default:
                  signatureKeySequence = "";
                  break;
          }

          // crop sequence
          signatureKeySequence = signatureKeySequence.substr(0, KONAMI_CODE.length);

          // check for konami code
          if (signatureKeySequence == KONAMI_CODE) {
              dispatchEvent(new Event("success"));
              signatureKeySequence = "";
          }

      }
     ]]>
    </mx:Script>

</mx:UIComponent>

to test it

<?xml version="1.0" encoding="utf-8"?>
<mx:Application xmlns:mx="http://www.adobe.com/2006/mxml" layout="vertical" xmlns:konamicode="konamicode.*">
    <mx:Script>
     <![CDATA[
      import mx.controls.Alert;
     ]]>
    </mx:Script>
    <konamicode:KonamiCodeCatch success="Alert.show('+30 lives!!!')" />
</mx:Application>

Answer 1

You may use Casalib. There are classes, Key and KeyCombo. You may listen for KeyComboEvent.SEQUENCE.

Working sample:

<?xml version="1.0" encoding="utf-8"?>
<mx:Application xmlns:mx="http://www.adobe.com/2006/mxml" layout="absolute" initialize="init();">
    <mx:Script>
     <![CDATA[
      import mx.controls.Alert;

      import org.casalib.events.KeyComboEvent;
      import org.casalib.ui.Key;
      import org.casalib.ui.KeyCombo;
      import org.casalib.util.StageReference;

      private const KONAMI_CODE:KeyCombo = new KeyCombo([Keyboard.UP,Keyboard.UP,Keyboard.DOWN,Keyboard.DOWN,Keyboard.LEFT,Keyboard.RIGHT,Keyboard.LEFT,Keyboard.RIGHT,("B").charCodeAt(),("A").charCodeAt()]);

      private function init():void {
       StageReference.setStage(this.systemManager.stage);

       Key.getInstance().addKeyCombo(KONAMI_CODE);
       Key.getInstance().addEventListener(KeyComboEvent.SEQUENCE,onKonami);
      }

      private function onKonami(evt:KeyComboEvent):void {
       if (evt.keyCombo == KONAMI_CODE){
        Alert.show("You know Konami code?","WOW");
       }
      }
     ]]>
    </mx:Script>
</mx:Application>

Answer 2

A state machine is fun to write, but in this case I'd go with a signature pattern. Depending on where you want to put the handler (on the stage of the component), here's some code that should work, though you can probably tighten it (and of course customize it to your specific need):

// up-up-down-down-left-right-left-right-B-A
public static const KONAMI_CODE:String = "UUDDLRLRBA";

// signature
private var signatureKeySequence:String = "";

private function onKeyDown(event:KeyboardEvent):void {
    var keyCode:int = event.keyCode;

    switch (keyCode) {
        case Keyboard.UP:
            signatureKeySequence += "U";
            break;

        case Keyboard.DOWN:
            signatureKeySequence += "D";
            break;

        case Keyboard.LEFT:
            signatureKeySequence += "L";
            break;

        case Keyboard.RIGHT:
            signatureKeySequence += "R";
            break;

        case Keyboard.B:
            signatureKeySequence += "B";
            break;

        case Keyboard.A:
            signatureKeySequence += "A";
            break;

        default:
            signatureKeySequence = "";
            break;
    }

    // crop sequence
    signatureKeySequence = signatureKeySequence.substr(0, KONAMI_CODE.length);

    // check for konami code
    if (signatureKeySequence == KONAMI_CODE) {
        // 30 lives!
    }
}