Screen Orientation

You have to listen for the specific event and call a function that does something...

                              stage.addEventListener(StageOrientationEvent.ORIENTATION_CHANGE, onChangeScreenOrientation);

private function onChangeScreenOrientation(e:StageOrientationEvent):void {

                              switch (e.afterOrientation) {

                                        case StageOrientation.DEFAULT :

      // something to do here;

                                        break;

                                        case StageOrientation.ROTATED_RIGHT : 

     // something to do here;

                                        break;

                                        case StageOrientation.UPSIDE_DOWN : 

     // something to do here;

                                        break;

                                        case StageOrientation.ROTATED_LEFT :

      // something to do here;

                                        break;

                              }