title: Flutter / Firebase project - Is `Unhandled Exception: Null check operator used on a null value` causing a blank screen?
body: <p>I'm working on a flutter project with firebase. I'm currently developing on a MacBook, using a simulated iPhone (just in case this is relevant). I am able to run my app, but when doing so it's just a white blank screen that never goes away, it may also be pertinent to know this happens on the Chrome, and simulated Android devices too. Looking in the <code>run</code> window, I can see I have an error showing the following:</p>
  <pre><code>Launching lib/main.dart on iPhone 13 in debug mode...
  Running Xcode build...
  Xcode build done.                                           28.4s
  Debug service listening on ws://127.0.0.1:61474/fF4XR-ozS5s=/ws
  Syncing files to device iPhone 13...
  [VERBOSE-2:ui_dart_state.cc(209)] Unhandled Exception: Null check operator used on a null value
  #0      MethodChannel.binaryMessenger (package:flutter/src/services/platform_channel.dart:121:86)
  #1      MethodChannel._invokeMethod (package:flutter/src/services/platform_channel.dart:146:36)
  #2      MethodChannel.invokeMethod (package:flutter/src/services/platform_channel.dart:329:12)
  #3      MethodChannel.invokeListMethod (package:flutter/src/services/platform_channel.dart:342:41)
  #4      MethodChannelFirebase._initializeCore (package:firebase_core_platform_interface/src/method_channel/method_channel_firebase.dart:31:37)
  #5      MethodChannelFirebase.initializeApp (package:firebase_core_platform_interface/src/method_channel/method_channel_firebase.dart:73:13)
  #6      Firebase.initializeApp (package:firebase_core/src/firebase.dart:42:47)
  #7      main (package:we_rise/main.dart:8:18)
  #8      _runMainZoned.&lt;anonymous closure&gt;.&lt;anonymous closure&gt; (dart:ui/hooks.dart:145:25)
  #9      _rootRun (dart:async/zon&lt;…&gt;
  </code></pre>
  <p>Since I'm still quite a novice, I can't quite decipher what has gone wrong, or what I'm looking at here. Please find below my <code>main.dart</code> file code:</p>
  <pre class="lang-dart prettyprint-override"><code>import 'package:firebase_core/firebase_core.dart';
  import 'package:flutter/material.dart';
  import 'package:flutter/services.dart';
  import 'database_config.dart';
  import 'launch_page.dart';
  
  void main() async {
    await Firebase.initializeApp(
      options: FirebaseOptions(
          apiKey: &quot;foo&quot;,//&quot;apiKey&quot;,
          appId: &quot;foo&quot;,//&quot;appId&quot;,
          messagingSenderId: &quot;foo&quot;,//&quot;messagingSenderId&quot;,
          projectId: &quot;foo&quot;),//&quot;projectId&quot;),
    );
    runApp(MyApp());
  }
  
  class MyApp extends StatelessWidget {
    @override
    Widget build(BuildContext context) {
      SystemChrome.setPreferredOrientations(
        [DeviceOrientation.portraitUp, DeviceOrientation.portraitDown],
      );
      return MaterialApp(
        theme: ThemeData(
          brightness: Brightness.light,
          fontFamily: 'BookmanOldStyle',
        ),
        home: LaunchPage(),
      );
    }
  }
  </code></pre>
  <p>I hope this is useful. I truly do not understand why it's presenting me with a blank white screen when the app loads. I also read <a href="https://stackoverflow.com/a/67990442/11094853">this answer</a>, but I don't think I've used a null check operator in my code. Any help, advice, and criticism is appreciated.</p>
  <p><em><strong>EDIT: ADDED FLUTTER DOCTOR OUTPUT</strong></em></p>
  <p><code>flutter doctor</code> output:</p>
  <pre class="lang-dart prettyprint-override"><code>Doctor summary (to see all details, run flutter doctor -v):
  [✓] Flutter (Channel stable, 2.5.3, on macOS 12.0.1 21A559 darwin-arm, locale en-GB)
  [✓] Android toolchain - develop for Android devices (Android SDK version 31.0.0)
  [✓] Xcode - develop for iOS and macOS
  [✓] Chrome - develop for the web
  [✓] Android Studio (version 2020.3)
  [✓] Connected device (2 available)
  
  • No issues found!
  </code></pre>
  <p><code>flutter doctor -v</code> output:</p>
  <pre><code>flutter doctor -v
  [✓] Flutter (Channel stable, 2.5.3, on macOS 12.0.1 21A559 darwin-arm, locale en-GB)
      • Flutter version 2.5.3 at /Users/me/Documents/flutter
      • Upstream repository https://github.com/flutter/flutter.git
      • Framework revision 18116933e7 (3 months ago), 2021-10-15 10:46:35 -0700
      • Engine revision d3ea636dc5
      • Dart version 2.14.4
  
  [✓] Android toolchain - develop for Android devices (Android SDK version 31.0.0)
      • Android SDK at /Users/me/Library/Android/sdk
      • Platform android-31, build-tools 31.0.0
      • Java binary at: /Applications/Android Studio.app/Contents/jre/Contents/Home/bin/java
      • Java version OpenJDK Runtime Environment (build 11.0.10+0-b96-7249189)
      • All Android licenses accepted.
  
  [✓] Xcode - develop for iOS and macOS
      • Xcode at /Applications/Xcode.app/Contents/Developer
      • Xcode 13.2.1, Build version 13C100
      • CocoaPods version 1.11.2
  
  [✓] Chrome - develop for the web
      • Chrome at /Applications/Google Chrome.app/Contents/MacOS/Google Chrome
  
  [✓] Android Studio (version 2020.3)
      • Android Studio at /Applications/Android Studio.app/Contents
      • Flutter plugin can be installed from:
         https://plugins.jetbrains.com/plugin/9212-flutter
      • Dart plugin can be installed from:
         https://plugins.jetbrains.com/plugin/6351-dart
      • Java version OpenJDK Runtime Environment (build 11.0.10+0-b96-7249189)
  
  [✓] Connected device (2 available)
      • iPhone 13 (mobile) • C0D4EC95-07AF-46AB-A35E-F2B9F4437875 • ios            • com.apple.CoreSimulator.SimRuntime.iOS-15-2 (simulator)
      • Chrome (web)       • chrome                               • web-javascript • Google Chrome 97.0.4692.71
  
  • No issues found!
  </code></pre>