如何在List前面显示图标

[Embed(source='assets/png/Circle.png')]
    
    private static var point:Class;
    [Bindable]
    [Embed(source='assets/png/Polyline.png')]
    private static var polyline:Class;
    [Bindable]
    [Embed(source='assets/png/Polygon.png')]
    private static var polygon:Class;	

private var layerType:ArrayCollection =
		            new ArrayCollection([{label:"点",tp:TableInfo.TableLayerTypePOINT,icon:point},
		                {label:"线",tp:TableInfo.TableLayerTypeLINE,icon:polyline},
		                {label:"面",tp:TableInfo.TableLayerTypePOLYGON,icon:polygon}]);