explodeIndex property
Index of the slice to explode it at the initial rendering.
Defaults to null.
Widget build(BuildContext context) {
   return Container(
       child: SfCircularChart(
           series: <DoughnutSeries<ChartData, String>>[
               DoughnutSeries<ChartData, String>(
                 explode: true,
                 explodeIndex: 2
               ),
           ],
       )
   );
}
Implementation
final int? explodeIndex;