When dynamically creating DropDownButton - it doesn't work - flutter

Question

When creating a DropDownButton through a class, the dropdown list itself does not open. Tell me, what is my mistake?
The button is in the "inactive" state. That is, when I click on it, I do not have a list with data
Yes, I'm sure the data is there.
I would not create a class for the button, but I have about 10 of them, and in order not to have a lot of repetitive code, I need to use the class
I can provide button code -
class DropDownButtons extends StatelessWidget {
final dynamic valueDropDown;
final String hintDropDown;
final List<DropdownMenuItem<dynamic>>? itemsDropDown;
final void Function(dynamic)? saveState;
const DropDownButtons({
Key? key,
required this.valueDropDown,
required this.hintDropDown,
required this.itemsDropDown,
required this.saveState
}) : super (key: key);
#override
Widget build(BuildContext context) {
return Container(
width: 270,
margin: EdgeInsets.only(top: 7),
child: Align(
alignment: Alignment.center,
child: DropdownButtonFormField(
hint: Text('hintDropDown'),
value: valueDropDown,
icon: const Icon(Icons.keyboard_arrow_down),
items: itemsDropDown,
onChanged: saveState,
)
)
);
}
}
And also, the display code -
DropDownButtons(valueDropDown: LoginClass.countryValue, hintDropDown: 'Text', itemsDropDown: LoginClass.countryDropDown, saveState: saveStateCountry()),
And of course, saving the stat -
saveStateCountry() {
(dynamic newValue) {
setState(() {
LoginClass.countryValue = newValue!;
print(LoginClass.countryValue);
});
};
}
minimum reproductive code -
class CreatedApplications extends StatelessWidget {
const CreatedApplications({Key? key}) : super(key: key);
#override
Widget build(BuildContext context) {
return MaterialApp(
debugShowCheckedModeBanner: false,
theme: ThemeData(
primarySwatch: Colors.blue,
),
home: MyHomePage(),
);
}
}
class MyHomePage extends StatefulWidget {
const MyHomePage({Key? key}) : super(key: key);
#override
_MyHomePageState createState() => _MyHomePageState();
}
class _MyHomePageState extends State<MyHomePage> {
saveStateCountry() {
(dynamic newValue) {
setState(() {
LoginClass.countryValue = newValue!;
print(LoginClass.countryValue);
});
};
}
#override
Widget build(BuildContext context) {
return Scaffold(
resizeToAvoidBottomInset: false,
body: SingleChildScrollView(
padding: EdgeInsets.all(15),
child: Column(children: [
Column(
children: <Widget>[
Align(
alignment: Alignment.center,
child: FractionallySizedBox(
widthFactor: 1,
alignment: Alignment.centerLeft,
child: Text('${now}'))),
],
),
SizedBox(
height: 12,
),
// const DropDown(),
DropDownButtons(valueDropDown: LoginClass.countryValue, hintDropDown: 'Выберите страну', itemsDropDown: LoginClass.countryDropDown, saveState: saveStateCountry()),
],
),
),
]
)
)
);
}
}
class DropDownButtons extends StatelessWidget {
final dynamic valueDropDown;
final String hintDropDown;
final List<DropdownMenuItem<dynamic>>? itemsDropDown;
final Function saveState;
const DropDownButtons({
Key? key,
required this.valueDropDown,
required this.hintDropDown,
required this.itemsDropDown,
required this.saveState
}) : super (key: key);
#override
Widget build(BuildContext context) {
return Container(
width: 270,
margin: EdgeInsets.only(top: 7),
child: Align(
alignment: Alignment.center,
child: DropdownButtonFormField(
decoration: InputDecoration(
border: OutlineInputBorder(
borderRadius: const BorderRadius.all(
const Radius.circular(25.0),
),
),
fillColor: Colors.lightBlueAccent.withOpacity(0.2),
filled: true
),
hint: Text(hintDropDown),
value: valueDropDown,
icon: const Icon(Icons.keyboard_arrow_down),
items: itemsDropDown,
onChanged: (dynamic newValue) {
saveState;
}
)
)
);
}
}