How to reference stage? Using flex for Facebook actionscript mobile API login method

Question

I'm trying to implement the 1.6 Mobile Facebook API (http://code.google.com/p/facebook-actionscript-api/downloads/detail?name=GraphAPI_Mobile_1_6.swc) into an Air for Android application. I've succesfully used the Web and Desktop API's however with the mobile app it's expecting an extra parameter to a stageReference, see:

login(callback:Function, stageRef:Stage, extendedPermissions:Array, webView:StageWebView = null)

But, using i'm using Flex and not Flash CS5, i can't just pass in this.stage or this or anything like that.

What exactly would you guys think I need to pass into that using Flash builder Flex? I can't seem to find any examples for the mobile actionscript API so i'm kinda in the dark, anyone have any ideas?

Here's the login information from the Mobile API Docs:

login   ()  method   
public static function login(callback:Function, stageRef:Stage, extendedPermissions:Array, webView:StageWebView = null):void
Opens a new login window so the current user can log in to Facebook.

Parameters

callback:Function — The method to call when login is successful. The handler must have the signature of callback(success:Object, fail:Object); Success will be a FacebookSession if successful, or null if not.

stageRef:Stage — A reference to the stage

extendedPermissions:Array — (Optional) Array of extended permissions to ask the user for once they are logged in.

webView:StageWebView (default = null) — (Optional) The instance of StageWebView to use for the login window For the most current list of extended permissions, visit http://developers.facebook.com/docs/authentication/permissions

Answer 1

If you're using Flex, you have FlexGlobals.topLevelApplication which will point to your mx:Application or s:Application so you can call stage on that to get a reference to it.

Otherwise, any DisplayObject attached to the stage or attached to another DisplayObject attached to the stage, will have it's stage property set (If it's not attached to anything, stage will be null).

Other than that, normally what people do is keep a static somewhere that they can access through the code, that's set when the program starts. For example, your typical main class could be something like:

package 
{
    import flash.display.Sprite;
    import flash.display.Stage;
    import flash.events.Event;

    public class Main extends Sprite 
    {

        public static var stage:Stage = null;

        public function Main():void 
        {
            // if we have our stage, go directly to _init(), otherwise wait
            if ( this.stage ) this._init();
            else this.addEventListener( Event.ADDED_TO_STAGE, this._init );
        }

        private function _init( e:Event = null ):void 
        {
            // remove the listener
            this.removeEventListener( Event.ADDED_TO_STAGE, this._init );

            // hold the stage
            Main.stage = this.stage;

            // do everything else
            ...
        }

    }

}

After that, anywhere in your code, you can call Main.stage to get access to the stage.