Question

I’m using Actionscript 2.0 for a mobile phone and can’t get my head around Events.

I’m creating a class object with all my code and using a group of functions (all as direct 1st level children of the class). There’s one function that creates a Movieclip with a square on it and sets the onPress event to another function called hit:

public function draw1Sqr(sName:String,pTL:Object,sSide:Number,rgb:Number){
    // create a movie clip for the Sqr
        var Sqr:MovieClip=this.canvas_mc.createEmptyMovieClip(sName,this.canvas_mc.getNextHighestDepth());
    // draw square
        Sqr.beginFill(rgb); 
        //etc  ...more lines        

    //setup properties (these are accessible in the event)
        Sqr.sSide=sSide;
        Sqr.sName=sName; 

    //setup event
        Sqr.onPress = hit; // this syntax seems to lead to 'this' within
                            // the handler function to be Sqr (movieclip)

        //Sqr.onPress = Delegate.create(this, hit); 
        //I've read a lot about Delegate but it seems to make things harder for me.
    }

Then in my event handler, I just cannot get the scope right…

public function hit(){
    for (var x in this){
        trace(x + " == " + this[x]);
    }
            //output results
                //onPress == [type Function]
                //sName == bSqr_7_4
                //sSide == 20

    trace(eval(this["._parent"])); //undefined
    trace(eval(this["._x"])); //undefined

}

For some reason, although the scope is set to the calling object (Sqr, a Movieclip) and I can access properties I defined, I can’t use the ‘native’ properties of a Movieclip object.

Any suggestions on how I can access the _x, _y and other properties of the Movieclip object that is pressed.

Answer 1

Use the array accessor or the dot accessor, but not both. For example:

trace(this._parent); // OR
trace(this["_parent"]);

As for the results of your iteration, I recall AS2 being screwy on this front. IIRC only dynamic properties are returned when looping with for … in. This prevents Objects (which often serve as hash maps) from including their native properties when all you want are the key/value pairs you set yourself.

Also – the eval() function can be easily overused. Unless you absolutely must execute a String of AS2 that you don’t have at compile-time I would recommend avoiding it. Happy coding!