How to select a default radio button in flutter - flutter

Question

I have implemented three radio buttons in my flutter project. But after executing the application, none of the radio buttons are showing selected. Can anyone help me where I am getting wrong please !
There is no radio button is getting selected although I click on it. I am unable to figure out the reason. Please help me solving it. Here is my code :
class AdminHomeContent extends StatefulWidget {
#override
_AdminHomeContentState createState() => _AdminHomeContentState();
}
class _AdminHomeContentState extends State<AdminHomeContent> {
static final Map<String, Color> options = {
'All': Colors.black, 'Cancelled':Colors.red,
'Pending': Colors.yellow, 'Visited': Colors.green[900],
};
List keyList = options.keys.toList();
List keyColor = options.values.toList();
String selectedOption = 'All';
int groupValue = 0 ;
void buttonValue(int v){
setState(() {
groupValue = v ;
});
}
#override
Widget build(BuildContext context) {
return ChangeNotifierProvider<PatientDataNotifier>(
create: (context) => PatientDataNotifier(),
child: MaterialApp(
home: Scaffold(
// some of my other codes
----------
-----------
//method that defines three radio buttons
Future<dynamic> getStatus(BuildContext context) {
return showDialog(
context: context,
builder: (BuildContext context) {
return AlertDialog(
content: SingleChildScrollView(
child: Container(
child: Column(
children: [
Row(
children: [
Radio(value: 1,
activeColor: Colors.blue,
groupValue: groupValue,
onChanged: (int v){
print(v);
buttonValue(v);
}
),
Text(keyList[2] , style: TextStyle(color: keyColor[2]),)
],
),
Row(
children: [
Radio(value: 2,
activeColor: Colors.blue,
groupValue: groupValue,
onChanged: (int v) {
print(v);
buttonValue(v);
}
),
Text(keyList[3] , style: TextStyle(color: keyColor[3]))
],
),
Row(
children: [
Radio(value: 3,
activeColor: Colors.blue,
groupValue: groupValue,
onChanged: (int v) {
print(v);
buttonValue(v);
}
),
Text(keyList[1] , style: TextStyle(color: keyColor[1]))
],
)
],
),
),
),
);
}
);
}
// some codes
------------------
-----------------
//calling the getStatus() inside the onTap() property of a Text
GestureDetector(
child: Text(patient.status,
style: getTextStyle('Poppins-Regular',15.0, FontWeight.bold, options[status]),
),
onTap: () async{
await getStatus(context);
},
),
}
}
None of the radio buttons are getting selected even after clicking on it. Please help me solving it.

Answer 1

First of all, none of Radio is selected by default because your initial groupValue is 0 and none of your Radio has this value.
Here a fully example of working Radio
class MyRadio extends StatefulWidget {
#override
_MyRadioState createState() => _MyRadioState();
}
int groupValue = 1;
class _MyRadioState extends State<MyRadio> {
#override
Widget build(BuildContext context) {
return MaterialApp(
theme: ThemeData.dark().copyWith(scaffoldBackgroundColor: darkBlue),
debugShowCheckedModeBanner: false,
home: Scaffold(
body: Center(
child: Column(
children: [
Radio(
value: 1,
activeColor: Colors.blue,
groupValue: groupValue,
onChanged: (int v) {
buttonValue(v);
},
),
Radio(
value: 2,
activeColor: Colors.blue,
groupValue: groupValue,
onChanged: (int v) {
buttonValue(v);
},
),
Radio(
value: 3,
activeColor: Colors.blue,
groupValue: groupValue,
onChanged: (int v) {
buttonValue(v);
},
),
],
),
),
),
);
}
void buttonValue(int v) {
setState(() {
groupValue = v;
});
}
}