Picture this case. You have a custom itemrenderer,( imagine a check box within a canvas for now) that performs a specific task and you want to reuse it on multiple columns. But how will the itemrenderer know which field in the arrayCollection is to be used to render itself appropriately?
Alright. Here is the trick.
There is this interface called IDropInListItemRenderer which your itemrenderer will have to implement to get access to listData which can be typeCasted to DataGridListData. The listData variable will hold reference to the owner of the itemRenderer and the hierarchy upwards. Following is the list of steps one has to follow.
1.Create the itemRenderer class that implements the IDropInListItemRenderer.
2.Create an instance variable to buffer the listData , namely _listData.
3.Override the set/get methods of the listData instance variable . In the setter, buffer the listData onto the instance variable
Following is the complete code
Create the datagrid and use the above created item renderer.
Ex:
The itemRenderer
package
{
import mx.containers.Canvas;
import mx.controls.CheckBox;
import mx.controls.dataGridClasses.DataGridListData;
import mx.controls.listClasses.BaseListData;
import mx.controls.listClasses.IDropInListItemRenderer;
public class sampleItemRenderer extends Canvas implements IDropInListItemRenderer
{
private var _listData:DataGridListData;
private var _instanceCheckBox:CheckBox = new CheckBox();
private var _currentDataFieldName:String = new String();
public function sampleItemRenderer()
{
super();
}
public function get listData():BaseListData
{
return _listData;
}
public function set listData(value:BaseListData):void
{
_listData = DataGridListData(value);
}
override protected function createChildren():void {
super.createChildren();
addChild(_instanceCheckBox);
}
override protected function updateDisplayList(unscaledWidth:Number, unscaledHeight:Number):void {
super.updateDisplayList(unscaledWidth,unscaledHeight);
_instanceCheckBox.selected = Boolean(data[_listData.dataField]);
}
}
}
