Questa e' una Classe trovata su WEB:

codice:
/**
* Singleton Tool Tip class AS3 Style
* @author Devon O. Wolfgang
*/

package com.onebyonedesign.utils {

    import flash.display.DisplayObjectContainer;
    import flash.display.Sprite;
    import flash.events.*;
    import flash.filters.DropShadowFilter;
    import flash.text.AntiAliasType;
    import flash.text.Font;
    import flash.text.TextField;
    import flash.text.TextFieldAutoSize;
    import flash.text.TextFormat;

    public class OBO_ToolTip extends Sprite {
        
        public static const ROUND_TIP:String = "roundTip";
        public static const SQUARE_TIP:String = "squareTip";
        
        private static var OBO_TT:OBO_ToolTip;
        
        private var _adv:Boolean;
        private var _tipText:TextField;
        private var _tipColor:uint;
        private var _tipAlpha:Number;
        private var _format:TextFormat;
        private var _ds:DropShadowFilter;
        private var _root:DisplayObjectContainer;
        private var _userTip:String;
        private var _orgX:int;
        private var _orgY:int;
        
        /**
        * singleton class - use static createToolTip() method for instantiation
        * @private
        */
        
        public function OBO_ToolTip(tc:TipCreator, myRoot:DisplayObjectContainer, font:Font, tipColor:uint = 0xFFFFFF, tipAlpha:Number = 1, tipShape:String = "roundTip", fontColor:uint = 0x000000, fontSize:int = 11, advRendering:Boolean = true) {
            if (!tc is TipCreator) throw new Error("OBO_ToolTip class must be instantiated with static method OBO_ToolTip.createToolTip() method.");
            
            _root = myRoot;
            _tipColor = tipColor;
            _tipAlpha = tipAlpha;
            _userTip = tipShape;
            _adv = advRendering;
            _format = new TextFormat(font.fontName, fontSize, fontColor);
            _ds = new DropShadowFilter(3, 45, 0x000000, .7, 2, 2, 1, 3);
            
            this.mouseEnabled = false;
        }
        
        /**
        * The OBO_ToolTip is a Singleton class which is instantiated using the the static method createToolTip(). It allows you to easily add tool tip items to DisplayObject instances.
        * 
        * @example The following example creates a simple red square Sprite instance then instantiates a tool tip instance which displays when the mouse rolls over the square:
        * <listing version="3.0">
        *  package {
        *
        *     import flash.display.Sprite;
        *     import com.onebyonedesign.utils.OBO_ToolTip;
        *     import flash.events.MouseEvent;
        *
        *         public class ToolTipExample extends Sprite {
        * 
        *         private var _toolTip:OBO_ToolTip;
        *         private var _mySprite:Sprite;
        *
        *         public function ToolTipExample() {
        *             _mySprite = drawSprite();
        *             _mySprite.x = 100;
        *             _mySprite.y = 100;
        *             addChild(_mySprite);
        *
        *             _toolTip = OBO_ToolTip.createToolTip(this, new LibraryFont(), 0x000000, .8, OBO_ToolTip.ROUND_TIP, 0xFFFFFF, 8, false);
        *          
        *             _mySprite.addEventListener(MouseEvent.ROLL_OVER, displayToolTip);
        *             _mySprite.addEventListener(MouseEvent.ROLL_OUT, removeToolTip);
        *         }
        * 
        *         private function displayToolTip(me:MouseEvent):void {
        *             _toolTip.addTip("This is a tool tip example.");
        *         }
        * 
        *         private function removeToolTip(me:MouseEvent):void {
        *             _toolTip.removeTip();
        *         }
        * 
        *         private function drawSprite():Sprite {
        *             var s:Sprite = new Sprite();
        *             s.graphics.beginFill(0xFF0000);
        *             s.graphics.drawRect(0, 0, 50, 50);
        *             s.graphics.endFill();
        *             return s;
        *         }
        *     }
        * }
        * </listing>
        * 
        * 
        * @param    myRoot      The "root" display object which will parent the tool tip.
        * @param    font            An instance of the embedded font class to use for the tool tip text.
        * @param    tipColor        The hexadecimal color of the tool tip.
        * @param    tipAlpha        The alpha of the tool tip (0 - 1).
        * @param    tipShape        The shape of the tool tip. Either <code>OBO_ToolTip.ROUND_TIP</code> or <code>OBO_ToolTip.SQUARE_TIP</code>.
        * @param    fontColor      The hexadecimal color of the tool tip's text.
        * @param    fontSize        The size of the tool tip text.
        * @param    advRendering    Recommend <code>false</code> for pixel fonts and <code>true</code> for others.
        * @return               A single instance of the OBO_ToolTip class.
        */
        public static function createToolTip(myRoot:DisplayObjectContainer, font:Font, tipColor:uint = 0xFFFFFF, tipAlpha:Number = 1, tipShape:String = "roundTip", fontColor:uint = 0x000000, fontSize:int = 11, advRendering:Boolean = true):OBO_ToolTip {
            if (OBO_TT == null) OBO_TT = new OBO_ToolTip(new TipCreator(), myRoot, font, tipColor, tipAlpha, tipShape, fontColor, fontSize, advRendering);
            return OBO_TT;
        }
        
        /**
        * Use this method to display the tool tip.
        * 
        * @param    words         The message the tool tip should display.
        * @return
        */
        public function addTip(words:String):void {
            _root.addChild(this);
            _tipText = new TextField();
            _tipText.mouseEnabled = false;
            _tipText.selectable = false;
            _tipText.defaultTextFormat = _format;
            _tipText.antiAliasType = _adv ? AntiAliasType.ADVANCED : AntiAliasType.NORMAL;
            _tipText.width = 1;
            _tipText.height = 1;
            _tipText.autoSize = TextFieldAutoSize.LEFT;
            _tipText.embedFonts = true;
            _tipText.multiline = true;
            _tipText.text = words;

            var w:Number = _tipText.textWidth;
            var h:Number = _tipText.textHeight;
            
            var tipShape:Array;
    
            switch (_userTip) {
                case ROUND_TIP :
                    tipShape = [[0, -13.42], [0, -2], [10.52, -15.7], [13.02, -18.01, 13.02, -22.65], [13.02, -16-h], [13.23, -25.23-h, 3.1, -25.23-h], [-w , -25.23-h], [-w -7, -25.23-h, -w - 7, -16-h], [-w - 7, -22.65], [-w - 7, -13.42, -w, -13.42]];
                    break;
                case SQUARE_TIP :
                    tipShape = [[-((w / 2) + 5), -16], [-((w / 2) + 5), -((18 + h) + 4)], [((w / 2) + 5), -((18 + h) + 4)], [((w / 2) + 5), -16], [6, -16], [0, 0], [-6, -16], [-((w / 2) + 5), -16]];
                    break;
                default :
                    throw new Error("Undefined tool tip shape in OBO_ToolTip!");
                    break;
            }
        
            var len:int = tipShape.length;
            this.graphics.beginFill(_tipColor, _tipAlpha);  
            for (var i:int = 0; i < len; i++) {
                if (i == 0) {
                    this.graphics.moveTo(tipShape[i][0], tipShape[i][1]);
                } else if (tipShape[i].length == 2) {
                    this.graphics.lineTo(tipShape[i][0], tipShape[i][1]);
                } else if (tipShape[i].length == 4) {
                    this.graphics.curveTo(tipShape[i][0], tipShape[i][1], tipShape[i][2], tipShape[i][3]);
                }
            }
            this.graphics.endFill();
            
            this.x = stage.mouseX;
            this.y = stage.mouseY;
            this.filters = [_ds];
            _tipText.x = (_userTip == ROUND_TIP) ? Math.round(-w) : Math.round(-(w / 2)) - 2;
            _orgX = _tipText.x;
            _tipText.y = Math.round(-21 - h);
            _orgY = _tipText.y;
            this.addChild(_tipText);
            
            stage.addEventListener(MouseEvent.MOUSE_MOVE, onTipMove);
        }
        
        private function onTipMove(me:MouseEvent):void {
            this.x = Math.round(me.stageX);
            this.y = Math.round(me.stageY - 2);
            
            if (this.y - this.height < 0) {
                this.scaleY = _tipText.scaleY = - 1;
                _tipText.y = (_userTip == ROUND_TIP) ? - 18 : -16;
                this.y = Math.round(me.stageY  + 5);
             } else {
                this.scaleY = _tipText.scaleY = 1;
                _tipText.y = _orgY;
            }

            if (this.x - (this.width - 18) < 0) {
                if (_userTip == ROUND_TIP) {
                    this.scaleX = _tipText.scaleX  = - 1;
                    _tipText.x = 5;
                }
            } else {
                this.scaleX = _tipText.scaleX = 1;
                _tipText.x = _orgX;
            }
            
            me.updateAfterEvent();
        }
        
        /**
        * Use this method to remove the tool tip.
        * 
        * @return
        */
        public function removeTip():void {
            stage.removeEventListener(MouseEvent.MOUSE_MOVE, onTipMove);
            this.removeChild(_tipText);
            this.graphics.clear();
            _root.removeChild(this);
        }
        
        /**
        * Sets the shape of the tool tip. Valid arguments are the strings <code>OBO_ToolTip.ROUND_TIP</code> (or "roundTip") and <code>OBO_ToolTip.SQUARE_TIP</code> (or "squareTip"). Anything else will throw an error.
        *       
        * @return
        */
        public function set tipShape(shape:String):void {
            if (shape != ROUND_TIP && shape != SQUARE_TIP) throw new Error("Invalid tip shape \""+ shape + "\" specified at OBO_ToolTip.tipShape.");
            _userTip = shape;
        }
    }
    
}

internal class TipCreator {};


la mia chiamata dalla root:

codice:
import classes.ActionScript3.OBO_ToolTip;

var ToolTipClass:OBO_ToolTip = new OBO_ToolTip(); 


// al passaggio nel mio MovieClip ---
mcMioMovieClip.addEventListener(MouseEvent.ROLL_OVER, toolTipShow);
function toolTipShow(e:MouseEvent):void
{
	ToolTipClass.addTip("pippo");
}

mcMioMovieClip.addEventListener(MouseEvent.ROLL_OUT, toolTipRemove);
function toolTipRemove(e:MouseEvent):void
{
	ToolTipClass.removeTip();
}

Problema: Che parametri passo al Costruttore ???