Invalid constructor name and Undefined class - mobile

Question

am trying to make an instance of ClassOne in ClassTwo in the code below, however I get errors Invalid constructor name and Undefined class 'instOne .person how do I do this the right way
class ClassOne extends StatefulWidget {
#override
ClassOneState createState() => ClassOneClassState();
}
class ClassOneState extends State<ClassOneClass> {
var person= 'myname';
hey(){
print('hey hello');
}
#override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(),
body: ListView(
children: <Widget>[
],
),
);
}
}}
// the file is in main.dart
import 'package:cloud_fs_demo/main.dart' ;
class ClassTwo extends StatefulWidget {
#override
ClassTwoState createState() => ClassTwoClassState();
}
class ClassTwoState extends State<ClassTwoClass> {
ClassOne instOne = ClassOne();
//Undefined class 'instOne .person'
instOne .person;
//error:Invalid constructor name
instOne .hey() ;
#override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(),
body: ListView(
children: <Widget>[
],
),
);
}
}}

Answer 1

you can create instance of ClassOne in ClassTwo because you are defining a field but think about this : when this code will execute ? instOne.person; . now to solve the problem you have to execute this code in the constructor function or in the initstate of the widget and the difference between them that the constructor method is executed first
in the constructor function
var instone= ClassOne();
_ClassTwoState(){
instone.person="test";
}
in the initstate of the widget
#override
void initState() {
instone.person="test";
super.initState();
}
also you have to declare the fields and the functions you are going to use in ClassTwo not in ClassTwoState
class ClassOne extends StatefulWidget {
var person= 'myname';
hey(){
print('hey hello');
}
#override
ClassOneState createState() => ClassOneState();
}
full example