Exception: type ‘String’ is not a subtype of type ‘int’ of ‘index’

FutureBuilder(
future: futureproduct,
builder: (context, snapshot){
if (snapshot.hasData) {
superheros_length = snapshot!.data;
ListView.builder(
itemCount: superheros_length.length,
itemBuilder: (context, index) {
return Container(
child: Column(
mainAxisAlignment: MainAxisAlignment.center,
children: [
Row(
mainAxisAlignment:
MainAxisAlignment.spaceAround,
children:
Text(superheros_length.body[index].name),