Change Group Labels in AdvancedDataGrid

I'm trying to use an AdvancedDataGrid to display some grouped data. Normally flex displays this in a "tree view" with a folder icon represent the group. I need to group the data based on an integer ID field in my object, but I'd like the label for the folder icon to display the groupName field in my object.

Here's a little example:

{groupName: group1, ID: 1234}
{groupName: group2, ID: 5678}                            开发者_Go百科               

<mx:grouping>
    <mx:Grouping label="Group"> <--- The label of the whole column
      <mx:GroupingField name="ID">
    </mx:Grouping>
</mx:grouping>

Resulting output:

=== Group ===
+ 1234
  - child
  - child
+ 5678
  ...

But I'd really like to output:

=== Group ===
+ group1
  - child
  - child
+ group2
  ...

If anyone has any tips I'd appreciate it.

-- Dan

Have a look at GroupingField#groupingFunction. From the adobe docs:

A function that determines the label for this group. By default, the group displays the text for the field in the data that matches the filed specified by the name property. However, sometimes you want to group the items based on more than one field in the data, or group based on something that is not a simple String field. In such a case, you specify a callback function by using the groupingFunction property.

 private function myGroupingFunction(value:Object, field:GroupingField):String