Rendering checkboxes through a loop

You need to store all the checkvalues in a List:

class FilterList extends StatefulWidget {  @override  _FilterListState createState() => _FilterListState();} //creating a state for checkboxesclass _FilterListState extends State<FilterList> {  int i;  List<bool> checkvalue = new List<bool>.filled(12, false); // this is new  Widget _element(String id, int index) { // index added    return Row(      children: <Widget>[        Checkbox(          value: checkvalue[index], // [index] added          onChanged: (value) {            setState(              () {                checkvalue[index] = value; // [index] added              },            );          },        ),        Text('$id')      ],    );  } // A new Widget where I get to combine the checkboxes with their respective texts  @override  Widget build(BuildContext context) {    return ListView(      children: <Widget>[        for (i = 10; i <= 120; i = i + 10) _element('$i HP', i ~/ 10 - 1) // index added      ],// for loop for iterating the widget rendering//HP stands for horsepower...    );  }}