Simple solution for MOUSE_WHEEL events on Mac

Flash does not support the MOUSE_WHEEL event for Macs. I was hoping it would be supported in version 9, and again in Flash 10 but I'm still waiting. There have been a number of solutions out there, and the best one I've found is Gabriel Bucknall's MacMouseWheel code. It consists of an actionscript class and some javascript code that will work together to have the browser pass the mouse wheel events to your Flash code.

After reading an awesome article by Peter McBride called JavaScript and VBScript Injection in ActionScript 3, I've put together a single as3 class that fixes the MOUSE_WHEEL problem without the need for any external javascript code. It works on Safari, FireFox and Opera and probably Chrome when it becomes available on the Mac.

The trick was to inject the mouse handling javascript code using ExternalInterface. The code finds the DOM node for itself, intercepts and passes the mouse wheel events which are then disributed to the current InteractiveObject under the cursor.

An example of initialization would be:

class awesomeapp extends Sprite {
  public function awesomeapp() {
    addEventListener(Event.ADDED_TO_STAGE, stage_init);
  }
  private function stage_init(e:Event):void {
    MacMouseWheelHandler.init(stage);
    addEventListener(MouseEvent.MOUSE_WHEEL, wheel_event);
  }
}

Download the source (MIT license).