Drawer all white, nothing shows up

Question

I’m having trouble creating the SiderBar. The Drawer nothing appears. Everything is blank.

My man who calls this file is:

import 'package:Cardapio/consts/consts_app.dart';
import 'package:flutter/material.dart';

class AppBarHome extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    double screenWidth = MediaQuery.of(context).size.width;
    return Container(
      child: Scaffold(
        floatingActionButton: Padding(
          padding: EdgeInsets.only(right: 10, top: 60),
          child: FloatingActionButton(
            child: Icon(Icons.menu),
            backgroundColor: Colors.red,
            onPressed: () {
              Scaffold.of(context).openDrawer();
            },
          ),
        ),
        floatingActionButtonLocation: FloatingActionButtonLocation.endFloat,
        appBar: PreferredSize(
          preferredSize: Size.fromHeight(150),
          child: Stack(
            children: <Widget>[
              Positioned(
                top: -(240 / 3.5),
                left: screenWidth - (240 / 1.57),
                child: Opacity(
                  child:
                      Image.asset(ConstsApp.darkFire, height: 200, width: 200),
                  opacity: 0.2,
                ),
              ),
            ],
          ),
        ),
        drawer: Drawer(
          child: ListView(
            children: <Widget>[
              DrawerHeader(
                child: Text('Drawer Header'),
                decoration: BoxDecoration(
                  color: Colors.blue,
                ),
              ),
              ListTile(
                title: Text('Item 1'),
                onTap: () {
                  Navigator.pop(context);
                },
              ),
              ListTile(
                title: Text('Item 2'),
                onTap: () {
                  Navigator.pop(context);
                },
              ),
            ],
          ),
        ),
      ),
    );
  }
}

Answer 1

The problem is the mode that is calling Drawer. To work add a key in his Scaffold and then call it by clicking the button.

Example

import 'package:flutter/material.dart';

final Color darkBlue = Color.fromARGB(255, 18, 32, 47);

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

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      theme: ThemeData.dark().copyWith(scaffoldBackgroundColor: darkBlue),
      debugShowCheckedModeBanner: false,
      home: Scaffold(
        body: Center(
          child: AppBarHome(),
        ),
      ),
    );
  }
}

class AppBarHome extends StatelessWidget {
  final GlobalKey<ScaffoldState> _scaffoldKey = new GlobalKey<ScaffoldState>();

  @override
  Widget build(BuildContext context) {
    double screenWidth = MediaQuery.of(context).size.width;
    return Container(
      child: Scaffold(
        key: _scaffoldKey,
        floatingActionButton: Padding(
          padding: EdgeInsets.only(right: 10, top: 60),
          child: FloatingActionButton(
            child: Icon(Icons.menu),
            backgroundColor: Colors.red,
            onPressed: () {
              _scaffoldKey.currentState.openDrawer();              
            },
          ),
        ),
        floatingActionButtonLocation: FloatingActionButtonLocation.endFloat,
        appBar: AppBar(title: Text("Titulo")),
        drawer: Drawer(
          child: ListView(
            children: <Widget>[
              DrawerHeader(
                child: Text('Drawer Header'),
                decoration: BoxDecoration(
                  color: Colors.blue,
                ),
              ),
              ListTile(
                title: Text('Item 1'),
                onTap: () {
                  Navigator.pop(context);
                },
              ),
              ListTile(
                title: Text('Item 2'),
                onTap: () {
                  Navigator.pop(context);
                },
              ),
            ],
          ),
        ),
      ),
    );
  }
}

So it works normally yours Drawer.

I noticed that in the image posted in the question there are particularities that were not shown in your code, such as the non-existence of AppBar. I added it to the screen just so the code could be working on Dartpad.