xxxxxxxxxx
import 'package:flutter/material.dart';
// Step 1
import 'package:flutter/services.dart';
import 'device_orientation/device_orientation_demo.dart';
void main() {
// Step 2
WidgetsFlutterBinding.ensureInitialized();
// Step 3
SystemChrome.setPreferredOrientations([
DeviceOrientation.portraitUp,
DeviceOrientation.portraitDown,
]).then((value) => runApp(MyApp()));
runApp(MyApp());
}