Datagrid smooth scrolling.. Don't want default row jump behaviour..

Question

Hi All,
      I am displaying large amount of data and each row contains itemrenderer Text. and this Text control displays large amount of data with in that... Whats the problem here is When we scroll vertically it goes jump into another row with showing total data.. I think this is a default property of datagrid. I just want avoid that and I need smooth scrolling of rows.. Can any one have any ideas about this.. any help can appriciable..
Thanks
Ram

Answer 1

Hi Alex,
       That was great job. You have implemented smooth scrolling for List..  Based upon that I have implemented the same in datagrid also..But I am facing couple of issues...
    1.  I have Item renderer Text.. With in that text I am displaying almost 90 records and it has a huge height. Accordingly the row height must change .. But what happend in my case is the data is overlapped on the second row.. the row height changes to certain height. after that it is not expanding.. records are displaying and overlapped on the second row and if it still lengthy it displayed on the third row also... so How can I solve this issue.. The row height must vary with the itemrenderer..
2. Second one is If I scroll vertically it is scrolling smoothly fine. But If I release the mouse the scroller going to Row end position or row starting position..
        I just want to fix the scroller position where user releases the Mouse from the vertical scrollbar...
      Can you please help me on this .. It is urgent  ..... I am posting my Datagrid code here...
package view.components.grid
    import flash.display.DisplayObject;
    import flash.events.Event;
    import mx.controls.Alert;
    import mx.controls.DataGrid;
    import mx.events.ScrollEvent;
    import mx.events.ScrollEventDetail;
    public class CustomGrid extends DataGrid
        private var fudge:Number;
        public function CustomGrid()
            super();
            offscreenExtraRowsOrColumns = 2;
        override protected function configureScrollBars():void
            super.configureScrollBars();
            if (verticalScrollBar)
                verticalScrollBar.lineScrollSize = .125;  // should be inverse power of 2
        override public function get verticalScrollPosition():Number
            //Alert.show("You are in vertical scroll Position handler");       
            if(!isNaN(fudge))
                var vsp:Number = super.verticalScrollPosition + fudge;
                fudge = NaN;
                return vsp;
            return Math.floor(super.verticalScrollPosition);
        override protected function scrollHandler(event:Event):void
            // going backward is trickier.  When you cross from, for instance 2.1 to 1.9, you need to convince
            // the superclass that it is going from 2 to 1 so the delta is -1 and not -.2.
            // we do this by adding a fudge factor to the first return from verticalScrollPosition
            // which is used by the superclass logic.
            var last:Number = super.verticalScrollPosition;
            var vsp:Number = verticalScrollBar.scrollPosition;
            if (vsp < last)
                if (last != Math.floor(last) || vsp != Math.floor(vsp))
                    if (Math.floor(vsp) < Math.floor(last))
                        fudge = Math.floor(last) - Math.floor(verticalScrollBar.scrollPosition);
                        trace(last.toFixed(2), vsp.toFixed(2), fudge);
            super.scrollHandler(event);
            var pos:Number = super.verticalScrollPosition;
            // if we get a THUMB_TRACK, then we need to calculate the position
            // because it gets rounded to an int by the ScrollThumb code, and
            // we want fractional values.
            if (event is ScrollEvent)
                var se:ScrollEvent = ScrollEvent(event);
                if (se.detail == ScrollEventDetail.THUMB_TRACK)
                    if (verticalScrollBar.numChildren == 4)
                        var downArrow:DisplayObject = verticalScrollBar.getChildAt(3);
                        var thumb:DisplayObject = verticalScrollBar.getChildAt(2);
                        pos = (thumb.y - downArrow.height) / (downArrow.y - thumb.height - downArrow.height) * maxVerticalScrollPosition;
                        // round to nearest lineScrollSize;
                        pos /= verticalScrollBar.lineScrollSize;
                        pos = Math.round(pos);
                        pos *= verticalScrollBar.lineScrollSize;
                        //trace("faked", pos);
            var fraction:Number = pos - verticalScrollPosition;
            fraction *= rowHeight;
            //trace("was", listContent.y.toFixed(2));
            listContent.move(listContent.x, viewMetrics.top + listContent.topOffset - fraction);
            //trace("now", listContent.y.toFixed(2), fraction.toFixed(2), listItems[0][0].data.lastName);