Creating model with contains list of widget flutter - flutter

Question

hii i'm a newbie in flutter and now i'm creating screen model(screen_model.dart) like this
class ScreenModel{
final String title;
final Widget screen;
final List<Widget> actions;
ScreenModel({#required this.titleScreen, #required this.widgetScreen, this.actions});
}
then when i try to initialize model in main.dart
final List<Widget> defaultActions = [
IconButton(
icon: Icon(Icons.filter_list, color: Colors.white), onPressed: null),
IconButton(icon: Icon(Icons.add, color: Colors.white), onPressed: null)
];
final List<ScreenModel> _widgetOptions = [
ScreenModel(title: 'Purchasing', screen: PurchasingScreen(),actions: defaultactions)
];
i get an error "The instance member 'defaultActions' can't be accessed in an initializer.
Try replacing the reference to the instance member with a different expression"
how to fix this?
thanks in advance

Answer 1

You can copy paste run full code below
You can use init _widgetOptions in initState()
List<ScreenModel> _widgetOptions;
#override
void initState() {
_widgetOptions = [
ScreenModel(
title: 'Purchasing',
screen: PurchasingScreen(),
actions: defaultActions)
];
super.initState();
}
working demo
full code
import 'package:flutter/material.dart';
class ScreenModel {
final String title;
final Widget screen;
final List<Widget> actions;
ScreenModel({#required this.title, #required this.screen, this.actions});
}
void main() {
runApp(MyApp());
}
class MyApp extends StatelessWidget {
#override
Widget build(BuildContext context) {
return MaterialApp(
title: 'Flutter Demo',
theme: ThemeData(
primarySwatch: Colors.blue,
visualDensity: VisualDensity.adaptivePlatformDensity,
),
home: MyHomePage(title: 'Flutter Demo Home Page'),
);
}
}
class MyHomePage extends StatefulWidget {
MyHomePage({Key key, this.title}) : super(key: key);
final String title;
#override
_MyHomePageState createState() => _MyHomePageState();
}
class _MyHomePageState extends State<MyHomePage> {
final List<Widget> defaultActions = [
IconButton(
icon: Icon(Icons.filter_list, color: Colors.blue), onPressed: null),
IconButton(icon: Icon(Icons.add, color: Colors.blue), onPressed: null)
];
List<ScreenModel> _widgetOptions;
#override
void initState() {
_widgetOptions = [
ScreenModel(
title: 'Purchasing',
screen: PurchasingScreen(),
actions: defaultActions)
];
super.initState();
}
#override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(
title: Text(widget.title),
),
body: Center(
child: Column(
mainAxisAlignment: MainAxisAlignment.center,
children: _widgetOptions[0].actions,
),
),
);
}
}
class PurchasingScreen extends StatelessWidget {
#override
Widget build(BuildContext context) {
return Container();
}
}