2 Replies Latest reply on May 3, 2011 9:52 AM by Flex harUI

    Datagrid smooth scrolling...

    flex4 Level 2

      Hi Alex/ All,


             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()
                  offscreenExtraRowsOrColumns = 2;
              override protected function configureScrollBars():void
                  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");       
                      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);
                  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);