Flutter Radio button not highlighting - flutter

Question

I built an app that has a list of users and a user can invite another user so I wanted the user to select multiple users at once and call the invite function I'm trying to accomplish this using a radio list tile button and when the user tap, it adds the user id to a list then when the user submits, the list is sent everything works fine but the problem is the radio list tile button group value does not get updated so the radio does not highlight so, the user does not know it's selected or not I have tried a lot of things but nothing seems to work so if anybody has an idea please help
List<String> users = [];
List<String> userName = ['A', 'N', 'A', 'W', 'J', 'Jo'];
void addRemoveFun(
String selectedVal,
) {
bool selected = users.contains(selectedVal);
if (selected) {
users.remove(selectedVal);
} else {
users.add(selectedVal);
}
}
Widget buildRadio(int index) {
return RadioListTile<List<String>>(
activeColor: ContentTheme.userPreffered(context).greenHighlightColor,
value: userName,
groupValue: selectedNames,
onChanged: (value) {
setState(() {
value = userName;
addRemoveFun(userName[index]);
});
print('$selectedNames');
},
title: Text(
"${userName[index]}",
style: TextStyle(
color: ContentTheme.userPreffered(context).bodyTextColor,
fontSize: ContentSize.fromMediaSize(widget.mediaSize).tileTitleSize,
),
),
);
}
}

Answer 1

Try this
Widget buildRadio(int index) {
return RadioListTile<List<String>>(
activeColor: ContentTheme.userPreffered(context).greenHighlightColor,
// Change userName to index
value: index,
// Change selectedNames to userName
groupValue: userName[index],
onChanged: (value) {
setState(() {
// Change here
userName = value;
addRemoveFun(userName[index]);
});
print('$selectedNames');
},
title: Text(
"${userName[index]}",
style: TextStyle(
color: ContentTheme.userPreffered(context).bodyTextColor,
fontSize: ContentSize.fromMediaSize(widget.mediaSize).tileTitleSize,
),
),
);
}
}