Flutter：[core/no-app] 没有创建 Firebase 应用“[DEFAULT]” - 调用 Firebase.initializeApp()

Question

我将 Firebase 软件包更新为最新版本：

  firebase_auth: ^0.18.0+1
  cloud_firestore: "^0.14.0+2"
  firebase_core: "0.5.0"

我还根据这篇文章在我的主要功能中添加了以下内容：

void main() async {
  WidgetsFlutterBinding.ensureInitialized();
  await Firebase.initializeApp();
  runApp(MyApp());
}

但是当我将应用程序留在模拟器的主屏幕并尝试返回应用程序时，我仍然收到此错误： [core/no-app] No Firebase App '[DEFAULT]' has been created - call Firebase.initializeApp()

似乎错误是在构建登录页面时引发的，所以这里是：

class LandingPage extends StatelessWidget {
  
  @override
  Widget build(BuildContext context) {
    AuthService auth = Provider.of<AuthService>(context, listen: false);
    return StreamBuilder<UserCustom>(
      stream: auth.onAuthStatechanged,
      builder: (context, snapshot){
        if(snapshot.connectionState == ConnectionState.active){
          UserCustom user = snapshot.data;
          if(user == null){
            return SignInPage.create(context);
          }
          return JobsScreen();
        }else{
          return Scaffold(body: Center(child: CircularProgressIndicator(),));
        }
      },
    );
  }
}