import 'package:flutter/material.dart';

void main() {
  runApp(
    MyApp(),
  );
}

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'Flutter Demo',
      theme: ThemeData(
        primarySwatch: Colors.blue,
      ),
      home: MyHomePage(),
    );
  }
}

class MyHomePage extends StatefulWidget {
  MyHomePage({Key key}) : super(key: key);

  @override
  _MyHomePageState createState() => _MyHomePageState();
}

class _MyHomePageState extends State<MyHomePage> {
  @override
  void initState() {
    // TODO: implement initState
    super.initState();
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      body: Container(
        color: Colors.green,
        alignment: Alignment.center,
        child: Text('center'),
      ),
      drawer: Container(
        color: Colors.red,
        alignment: Alignment.center,
        child: Text('left'),
      ),
      endDrawer: Container(
        color: Colors.blue,
        alignment: Alignment.center,
        child: Text('right'),
      ),
    );
  }
}

flutter doctor
Doctor summary (to see all details, run flutter doctor -v):
[✓] Flutter (Channel beta, v1.8.3, on Mac OS X 10.14.6 18G87, locale
    en-US)
 
[✓] Android toolchain - develop for Android devices (Android SDK version
    28.0.3)
[✓] Xcode - develop for iOS and macOS (Xcode 10.3)
[✓] Android Studio (version 3.5)
[!] IntelliJ IDEA Ultimate Edition (version 2018.1.2)
    ✗ Flutter plugin not installed; this adds Flutter specific
      functionality.
    ✗ Dart plugin not installed; this adds Dart specific functionality.
[✓] Connected device (1 available)

! Doctor found issues in 1 category.