how to keep screen in portrait mode flutter code example

Example 1: lock screen orientation flutter

<manifest xmlns:android="http://schemas.android.com/apk/res/android"    package="com.example.orientation_lock_example">    <application ...>        <activity            android:name=".MainActivity"            android:screenOrientation="portrait"            ...            />            ...         </activity>        ...     </application></manifest>

Example 2: flutter lock orientation

import 'package:flutter/material.dart';  import 'package:flutter/services.dart';   Future main() async {    await SystemChrome.setPreferredOrientations([DeviceOrientation.portraitUp]);    runApp(new MyApp());  }   class MyApp extends StatelessWidget {    @override      Widget build(BuildContext context) {      return MaterialApp(        title: 'Welcome to Flutter',        home: Scaffold(          appBar: AppBar(            title: Text('Flutter Display Orientation Tutorial'),          ),          body: Center(            child: Text(                "Woolha.com"            )          ),        ),      );    }  }