Skinning the Flash DataGrid

18 Feb06

transp_datagrid.jpgFor a current project, I needed a datagrid with partially transparent rows. No problem I thought - I’ll just extend the V2 datagrid and write my own versions of the required methods. All so simple in theory, not so simple in real life. There are two things that must be made transparent, the general component background and the background of each row. I first tried overwriting the methods I thought to control this but that did not work. The one who made the datagrid never thought that anyone would ever want partially transparent gridrows. The component just does not contain any code that enables this. Another thing is that no matter what you do, you cannot re-pack or alter the datagrid assets that are used to draw the grid.

The grids assets are stuck inside a SWC file and even if you rename the SWC to ZIP and extract the contents, you’ll find some of the assets to be inside a SWF. Reversing this SWF is out of the question. I’ve browsed the whole class hierarchy and I cannot find a place where the component background is drawn using scripting, so I’ve concluded that it must be embedded within the asset SWF. The same goes for the gridrow class. In theory, I could just change the beginFill-metod that tells how to draw the rows, but for some reason this won’t work. I tell it to use Alpha, but the setting is just ignored. Where to go next?

I browsed Flashcoders and searched the web. I found plenty of questions, but no solution. Most of these solutions required that you did work directly on the movieClips inside the grid and that’s also what I’ve concluded must be the solution. It is with the datagrid rows as with so many other components - they require a one frame pause to redraw all contents. Have you heard the saying “If in doubt - wait one frame”? If not, just try it and in maybe 50% of all cases, waiting one frame will solve your problems. You could solve this using Intervals, but as you also may know - too many intervals may kill your Flash movie. If they are not deleted properly, you’ll end up with an unresponsive application and deleting them can be a hassle. To the rescue comes my rather manual WaitXframes-class. Just specify a location to make a temporary movieClip and the handler to run once finished waiting. Easy to clean up and no intervals used. So here’s my solution:

import mx.controls.DataGrid;
import mx.styles.CSSStyleDeclaration;
import no.netron.utils.WaitXframes;
// Attach DataGrid
var rootObject:MovieClip = _root;
var my_dg = rootObject.theGrid;
my_dg.setStyle("alternatingRowColors", Array(0xEAEFF4, 0xF8FAFB));
// Add some dummy data
var myDP_array:Array = new Array();
myDP_array.push({name:"Clark",checked:false, score:3135});
myDP_array.push({name:"Bruce",checked:true, score:403});
myDP_array.push({name:"Peter",checked:false, score:25});
my_dg.dataProvider = myDP_array;
// Move away from upper corner
my_dg.setSize(350, 200);
my_dg.move(20, 40);
// Turn off transparency for the main datagrid background clip
my_dg.border_mc._alpha = 0;
// Function to adjust transpareny of each row in grid
function fixAlpha(){
	var i = 10; // Rows always start on row ten
	while(my_dg.content_mc["listRow"+i] != undefined){
		my_dg.content_mc["listRow"+i]._alpha = 55;
s = new WaitXframes(rootObject,1,"fixAlpha",this);

I can’t post the FLA for this example without breaking the Macromedia EULA, but just add a datagrid to your library and paste this code in frame 1 to see it working. You may also want to add a background image to really see the transparency. This was also the first project where I used the XRay debugger extensively. Great tool for the output I get from the debugger in the Flash IDE is worthless.

If anyone reading this has a different take, please post it in the comments. I feel this is a downright dirty way to solve such a problem, but for now it’s the only way I’ve found…

18 February 2006 at 2:26 am

15 Responses to Skinning the Flash DataGrid

  1. avatar photo
    Kevin Hoyt 18 February 2006 at 6:01 am #

    I can completely relate to the difficulty of skinning the v2 components.  Since these were the base for Flex 1.x components, it’s not much easier there.  I know this isn’t of any consolation right now, but for what it’s worth, almost all the Flex 2 components have numerous transparency options right out of the box.  I put together a simple example that mirrors your problem in MXML.  I also included an extra few lines of code to make the “true/false” column into a CheckBox.

  2. avatar photo
    stef 18 February 2006 at 8:16 am #
  3. avatar photo
    Jensa 18 February 2006 at 3:23 pm #

    Hi Kevin,

    Most styles applying to the DataGrid can be found under the help entries for the List Class, but there’s no link in the docs from the DataGrid to the List class? It would be really useful to have one page per class/component listing all the valid styles for each component, complete with what classes they inherit the styles from. Now I have to hunt through the class inheritance tree/docs to find all the supported styles.


  4. avatar photo
    Kevin Hoyt 19 February 2006 at 9:07 am #

    Standardizing the class library into a consistent and cohesive framework that can be leveraged across both Flex and Flash authoring is a big part of what the whole Flex Framework 2 is all about.  I can’t say (because I don’t know) what the Flash authoring team has up their sleeves in the future, but I would expect this to be on this list.

    As it stands today, Flex 1.x has done a great job of taking this first step.  Take a look at the DataGrid documentation (Flex) below.  If you scroll down you’ll see all the styles you can apply including those styles that are inherited. 

  5. avatar photo
    PhilFlash 19 February 2006 at 6:01 pm #

    _global.styles.ScrollSelectList.backgroundColor = undefined;
    if (newClr == undefined) {
      mc.beginFill(0xABCDEF, 0);
    } else {
    mc.drawRect(1, 0, this.__width, this.__height);
    mc._width = this.__width;
    mc._height = this.__height;
    and don’t use

    FYI, WaitXframes is not neccessary in your code.
    my_dg.doLater(this, “fixAlpha”);


  6. avatar photo
    Jensa 19 February 2006 at 6:48 pm #


  7. avatar photo
    Spook 05 March 2006 at 12:17 am #

    Muchas gracias!

    Thanks for share your knowledge with the other people.

  8. avatar photo
    IOG 12 April 2006 at 9:10 pm #
  9. avatar photo
    Jensa 18 April 2006 at 4:42 pm #


  10. avatar photo
    Ed 26 July 2006 at 2:32 am #

    I added a checkbox control into the datagrid, however when I set the _alpha property the checkboxes disappeared too? any ideas?

  11. avatar photo
    Dano 28 August 2006 at 10:52 am #

    Very helpful!

    //Alpha background really
    dg.content_mc[“listRow”+i].backGround._alpha = 55;

    //Invisible, useful for print without background
    dg.content_mc[“listRow”+i].backGround._visible = false;

  12. avatar photo
    Dano 28 August 2006 at 11:01 am #

    Very helpful!

    //Visible false, very helpful to print
    dg.content_mc[“listRow”+i].backGround._visible = false;
    //Really alpha background
    dg.content_mc[“listRow”+i].backGround._alpha = 55;


  13. avatar photo
    Brad 04 October 2006 at 5:32 am #

    I’m just beginning to delve into the world of Flash and I must say I am quite excited to see that Flash has support for datagrids.  I have always been very disappointed with all of the PHP datagrids I’ve been able to find.

  14. avatar photo
    Kaan 12 October 2006 at 1:26 pm #

    my name is kaan
    i want use my grid html code. I how do?

  15. avatar photo
    Geoff 04 February 2007 at 12:15 pm #

    Hi, Is it possible to also make the header row transparent?

    If so, how?