how to shuffle a list in flutter - flutter

Question

i am adding shuffle() function but the error is showing Another exception was thrown: type 'String' is not a subtype of type 'int' of 'index' is there any solution to put question in shuffle i don't know where to add this shuffle function there was not any error in this project the json files is added with this code
i am adding mydata.shuffle() in this code
#override
Widget build(BuildContext context) {
setasset();
return FutureBuilder(
future:
DefaultAssetBundle.of(context).loadString(assettoload, cache: false),
builder: (context, snapshot) {
List? mydata = json.decode(snapshot.data.toString());
if (mydata == null) {
return Scaffold(
body: Center(
child: Text(
"Loading",
),
),
);
} else {
return quizpage(mydata: mydata);
}
},
);
}
}
class quizpage extends StatefulWidget {
final List mydata;
quizpage({required this.mydata});
#override
_quizpageState createState() => _quizpageState();
}
class _quizpageState extends State<quizpage> {
_quizpageState();
Color colortoshow = Colors.indigoAccent;
int marks = 0;
int i = 1;
bool disableAnswer = false;
// extra varibale to iterate
int timer = 30;
String showtimer = "30";
Map<String, Color> btncolor = {
"a": Colors.indigo.shade900,
"b": Colors.indigo.shade900,
"c": Colors.indigo.shade900,
"d": Colors.indigo.shade900,
};
bool canceltimer = false;
#override
void initState() {
starttimer();
super.initState();
}
#override
void setState(fn) {
if (mounted) {
super.setState(fn);
}
}
void starttimer() async {
const onesec = Duration(seconds: 1);
Timer.periodic(onesec, (Timer t) {
setState(() {
if (timer < 1) {
t.cancel();
nextquestion();
} else if (canceltimer == true) {
t.cancel();
} else {
timer = timer - 1;
}
showtimer = timer.toString();
});
});
}
void nextquestion() {
canceltimer = false;
timer = 30;
setState(() {
if (i < 10) {
i++;
} else {
Navigator.of(context).pushReplacement(MaterialPageRoute(
builder: (context) => resultpage(marks: marks),
));
}
btncolor["a"] = Colors.indigo.shade900;
btncolor["b"] = Colors.indigo.shade900;
btncolor["c"] = Colors.indigo.shade900;
btncolor["d"] = Colors.indigo.shade900;
disableAnswer = false;
});
starttimer();
}
void checkanswer(String k) {
if (widget.mydata[2][i.toString()] == widget.mydata[1][i.toString()][k]) {
marks = marks + 5;
} else {}
setState(() {
btncolor[k] = colortoshow;
canceltimer = true;
disableAnswer = true;
});
Timer(Duration(seconds: 2), nextquestion);
}
Widget choicebutton(String k) {
return Padding(
padding: EdgeInsets.symmetric(
vertical: 10.0,
horizontal: 20.0,
),
child: SizedBox(
height: 60,
width: 400,
child: OutlinedButton(
onPressed: () => checkanswer(k),
child: Text(
widget.mydata[1][i.toString()][k] ?? "",
style: TextStyle(
fontWeight: FontWeight.w600,
color: Colors.black,
fontFamily: "Alike",
fontSize: 18.0,
),
maxLines: 1,
),
style: OutlinedButton.styleFrom(
side: BorderSide(width: 3.0, color: Colors.indigo.shade900),
backgroundColor: Colors.transparent,
shape: const StadiumBorder()),
),
),
);
}
#override
Widget build(BuildContext context) {
SystemChrome.setPreferredOrientations(
[DeviceOrientation.portraitDown, DeviceOrientation.portraitUp]);
return WillPopScope(
onWillPop: () async {
return await showDialog(
context: context,
builder: (context) => AlertDialog(
title: Text(
"Quizstar",
),
content: Text("You Can't Go Back At This Stage."),
actions: <Widget>[
ElevatedButton(
onPressed: () {
Navigator.of(context).pop();
},
child: Text(
'Ok',
),
)
],
));
},
child: SafeArea(
child: Scaffold(
body: Column(
children: <Widget>[
Expanded(
flex: 3,
child: Container(
width: 500,
height: 200,
decoration: const BoxDecoration(
image: DecorationImage(
image: AssetImage(
"assets/canva4.png",
),
fit: BoxFit.cover,
),
),
padding: EdgeInsets.all(15.0),
alignment: Alignment.bottomLeft,
child: Text(
widget.mydata[0][i.toString()],
style: TextStyle(
color: Colors.white,
fontWeight: FontWeight.w700,
fontSize: 20.0,
fontFamily: "Quando",
),
),
),
),
Divider(height: 10, color: Colors.black, thickness: 10),
Expanded(
flex: 6,
child: AbsorbPointer(
absorbing: disableAnswer,
child: Container(
child: Column(
mainAxisAlignment: MainAxisAlignment.center,
children: <Widget>[
choicebutton('a'),
choicebutton('b'),
choicebutton('c'),
choicebutton('d'),
],
),
),
),
),
Expanded(
flex: 1,
child: Container(
alignment: Alignment.topCenter,
child: Center(
child: Text(
showtimer,
style: TextStyle(
fontSize: 35.0,
fontWeight: FontWeight.w700,
fontFamily: 'Times New Roman',
),
),
),
),
),
],
),
),
),
);
}
}