Flutter application hangs when calling await rootBundle.loadString(...) from main() - flutter

Question

I found this answer about storing global configuration into globals.dart.
How can I load configuration into it from assets/config.json?
I've tried like this:
import 'package:flutter/material.dart';
import 'package:flutter/services.dart';
import 'dart:convert';
import 'globals.dart' as globals;
void main() async {
globals.config = jsonDecode(await rootBundle.loadString('assets/config.json'));
runApp(MyApp());
}
class MyApp extends StatelessWidget {
...
}
The application starts with a white screen. Nothings happens, no errors. I guess that await rootBundle.loadString(...) causes the application to hang.

Answer 1

You can copy paste run full code below
You need to add WidgetsFlutterBinding.ensureInitialized() in main()
without this line will produce white screen
globals.dart
Map<String, dynamic> config = {};
config.json
{
"id": "1",
"name": "abc"
}
code snippet
void main() async{
WidgetsFlutterBinding.ensureInitialized();
globals.config = jsonDecode(await rootBundle.loadString('assets/config.json'));
runApp(MyApp());
}
pubspec.yaml
assets:
- assets/
working demo
full code
import 'package:flutter/material.dart';
import 'package:flutter/services.dart';
import 'dart:convert';
import 'globals.dart' as globals;
void main() async{
WidgetsFlutterBinding.ensureInitialized();
globals.config = jsonDecode(await rootBundle.loadString('assets/config.json'));
runApp(MyApp());
}
class MyApp extends StatelessWidget {
#override
Widget build(BuildContext context) {
return MaterialApp(
title: 'Flutter Demo',
theme: ThemeData(
primarySwatch: Colors.blue,
),
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> {
int _counter = 0;
void _incrementCounter() {
setState(() {
_counter++;
});
}
#override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(
title: Text(widget.title),
),
body: Center(
child: Column(
mainAxisAlignment: MainAxisAlignment.center,
children: <Widget>[
Text(globals.config["id"]),
Text(globals.config["name"]),
Text(
'You have pushed the button this many times:',
),
Text(
'$_counter',
style: Theme.of(context).textTheme.headline4,
),
],
),
),
floatingActionButton: FloatingActionButton(
onPressed: _incrementCounter,
tooltip: 'Increment',
child: Icon(Icons.add),
),
);
}
}