Demonstrating the Drawers and Bottom Sheet for the Scaffold widget

Scaffold_BottomSheet.dart

import 'package:flutter/foundation.dart';
import 'package:flutter/material.dart';

void main() => runApp(MyApp());

class MyApp extends StatefulWidget {
  MyApp({Key key}) : super(key: key);
  State createState() => _MyAppState();
}

class _MyAppState extends State<MyApp> {
  int _count = 0;
  final GlobalKey keyScaffold = new GlobalKey();
  String hasAppBar = '';
  String hasDrawer = '';
  String hasEndDrawer = '';
  String hasFloatingActionButton = '';
  String appBarMaxHeight = '';
  String isDrawerOpen = '';
  String isEndDrawerOpen = '';
  bool hadDrawerOpened = false;
  PersistentBottomSheetController<Null> sheet;
  @override
  Widget build(BuildContext context) {
    final title = 'Floating App Bar';
    final ThemeData theme = Theme.of(context);
    return MaterialApp(
      debugShowCheckedModeBanner: false,
      title: title,
      home: Scaffold(
        key: keyScaffold,
        appBar: AppBar(
          title: Text('Sample Code'),
        ),
        body: Center(
            child: Column(
          mainAxisAlignment: MainAxisAlignment.center,
          children: <Widget>[
            Text('You have pressed the button $_count times.'),
            RaisedButton(
              onPressed: () {
                ScaffoldState state = keyScaffold.currentState;
                if (hadDrawerOpened) {
                  if (state.hasEndDrawer) state.openEndDrawer();
                } else {
                  if (state.hasDrawer) state.openDrawer();
                }
                hadDrawerOpened = state.isDrawerOpen;
                setState(() {});
                sheet = state.showBottomSheet<Null>((BuildContext context) {
                  return Container(
                      child: Column(
                    mainAxisSize: MainAxisSize.min,
                    children: <Widget>[
                      Center(
                          child: Text(
                    'Opened ${hadDrawerOpened ? 'left' : 'right'}-hand Drawer!',
                      )),
                    ],
                  ));
                });
              },
              elevation: 20.0,
              textColor: theme.canvasColor,
              color: theme.primaryColor,
              child: Text('Open Drawers'),
            ),
          ],
        )),
        bottomNavigationBar: BottomAppBar(
          child: Container(
            height: 50.0,
          ),
        ),
        floatingActionButton: FloatingActionButton(
          onPressed: () => setState(() {
                _count++;
              }),
          tooltip: 'Increment Counter',
          child: Icon(Icons.add),
        ),
        floatingActionButtonLocation: FloatingActionButtonLocation.endFloat,
        drawer: _drawer,
        endDrawer: _drawer,
      ),
    );
  }

  Widget get _drawer => Drawer(
        // Add a ListView to the drawer. This ensures the user can scroll
        // through the options in the Drawer if there isn't enough vertical
        // space to fit everything.
        child: ListView(
          // Important: Remove any padding from the ListView.
          padding: EdgeInsets.zero,
          children: <Widget>[
            DrawerHeader(
              child: Text('Drawer Header'),
              decoration: BoxDecoration(
                color: Colors.blue,
              ),
            ),
            ListTile(
              title: Text('Item 1'),
              onTap: () {
                // Update the state of the app
                // ...
                // Then close the drawer
                Navigator.pop(context);
              },
            ),
            ListTile(
              title: Text('Item 2'),
              onTap: () {
                // Update the state of the app
                // ...
                // Then close the drawer
                Navigator.pop(context);
              },
            ),
          ],
        ),
      );
}