Adobe 官方资料收集
http://help.adobe.com/en_US/flex/using/WS0ab2a460655f2dc3-427f401412c60d04dca-7ff3.html#WS0ab2a460655f2dc3-427f401412c60d04dca-7ff2
引用Creating a header renderer
The DataGridSkin class uses the GridColumnHeaderGroup component to control the display of the column headers. The GridColumnHeaderGroup component displays a row of headers cells, where the vertical edges of the header cells are aligned with the grid columns.
The GridColumnHeaderGroup component arranges header renderer instances in a row, where the left and right edge of each renderer match the corresponding column. The renderers' height is the maximum preferred height for all of the displayed header renderers.
Like the Grid control and item renderers, the GridColumnHeaderGroup class only creates as many column header renderers and separators as are visible. Renderers and separators that have been scrolled out of view are recycled.
By default, the GridColumnHeaderGroup component uses the spark.skins.spark.DefaultGridHeaderRenderer class as the header renderer. To create a custom header renderer, define the renderer in MXML or ActionScript. Header renderers must implement the IGridItemRenderer interface.
Then, use the Grid.headerRenderer property to specify to use the custom renderer for the column.
Flex 4.5.1 sdk 下载
http://opensource.adobe.com/wiki/display/flexsdk/Download+Flex+4.5
