init a list with vars flutter - list

Question

I am trying to init a list of objects (it doesn't metter which object- they all give the same error), so for the example I am using Strings:
String str = 'str';
String str2 = 'str2';
List<String> strList = ["str", "str2"];
List<String> strList2 = [str, str2];
strList2.add(str);
strList is working fine, but I want to add objects from a server response, so I need to add vars, why does the strList2.add is telling me "he name of a constructor must match the name of the enclosing class." and "Try renaming one of the constructors."
I am new to flutter so its weird for me,
EDIT:
my test Class:
class test extends StatefulWidget {
#override
_testState createState() => _testState();
}
class _testState extends State<test> {
String str = 'str';
String str2 = 'str2';
List<String> strList = ["str", "str2"];
List<String> strList2 = [str, str2];
strList2.add(str);
#override
Widget build(BuildContext context) {
return Scaffold(
body: Text('testClass'),
);
}
}
thanks!

Answer 1

You can't use add() in the attributes definition. You need to use initState() like this :
class _testState extends State<test> {
String str = 'str';
String str2 = 'str2';
List<String> strList = ["str", "str2"];
List<String> strList2 = [str, str2];
#override
initState() {
super.initState();
strList2.add(str);
}
#override
Widget build(BuildContext context) {
return Scaffold(
body: Text('testClass'),
);
}

Answer 2

This code looks fine. The error message indicates that one of your class has a typo in it's constructor, hence the mismatch - for example:
class MySpecialWidget extends StatefulWidget {
const MySpecialWidgetXXX({Key key) : super(key: key); // <--- this produces the error you see
#override
_CreateMySpecialWidgetState createState() => _CreateMySpecialWidgetState();
}
If the error is really on the .add line, then my take is that you have a closing bracket problem somewhere maybe.