MissingPluginException when following trip planner tutorial

[Jordan-Nelson]

Issue created from comment on #2551.

---

Comment

Hi Jordan - I actually have a very similar issue. I'm following an AWS tutorial, which up until today, after I updated my Android SDK, I haven't had too much of an issue.

Here's my stuff - I'm a beginner at this so I might have messed something up, but it had been working fine until today.

Launching lib\main.dart on SM S901U in debug mode...
Running Gradle task 'assembleDebug'...
√  Built build\app\outputs\flutter-apk\app-debug.apk.
Installing build\app\outputs\flutter-apk\app.apk...
Debug service listening on ws://127.0.0.1:57740/L4njAY89pIo=/ws
Syncing files to device SM S901U...
I/ionsapplication( 7893): Compiler allocated 6075KB to compile void android.view.ViewRootImpl.performTraversals()
I/flutter ( 7893): Amplify plugin was not added
E/flutter ( 7893): [ERROR:flutter/runtime/dart_vm_initializer.cc(41)] Unhandled Exception: AmplifyException(message: Amplify plugin AmplifyAuthCognitoMethodChannel was not added successfully., recoverySuggestion: We currently don't have a recovery suggestion for this exception., underlyingException: AmplifyException(message: MissingPluginException(No implementation found for method addPlugin on channel com.amazonaws.amplify/auth_cognito), recoverySuggestion: null, underlyingException: null))
E/flutter ( 7893): #0      MethodChannelAmplify.addPlugin (package:amplify_flutter/src/method_channel_amplify.dart:66:7)
E/flutter ( 7893): <asynchronous suspension>
E/flutter ( 7893): #1      Future.wait.<anonymous closure> (dart:async/future.dart:522:21)
E/flutter ( 7893): <asynchronous suspension>
E/flutter ( 7893): #2      _configureAmplify (package:reaqtionsapplication/main.dart:28:3)
E/flutter ( 7893): <asynchronous suspension>
E/flutter ( 7893): #3      main (package:reaqtionsapplication/main.dart:12:5)
E/flutter ( 7893): <asynchronous suspension>
E/flutter ( 7893): 

Here's my main dart file

import 'package:reaqtionsapplication/reaqtions_app.dart';
import 'package:flutter/material.dart';
import 'package:amplify_flutter/amplify_flutter.dart';
import 'package:amplify_auth_cognito/amplify_auth_cognito.dart';
import 'package:flutter_riverpod/flutter_riverpod.dart';
import 'amplifyconfiguration.dart';

Future<void> main() async {
  WidgetsFlutterBinding.ensureInitialized();
  bool isAmplifySuccessfullyConfigured = false;
  try {
    await _configureAmplify();
    isAmplifySuccessfullyConfigured = true;
  } on AmplifyAlreadyConfiguredException {
    debugPrint('Amplify configuration failed.');
  }

  runApp(
    ProviderScope(
      child: ReAQtionsApp(
        isAmplifySuccessfullyConfigured: isAmplifySuccessfullyConfigured,
      ),
    ),
  );
}

Future<void> _configureAmplify() async {
  await Amplify.addPlugins([
    AmplifyAuthCognito(),
  ]);
  await Amplify.configure(amplifyconfig);
}

And here is the app file

import 'package:reaqtionsapplication/features/airquality/ui/aqi_list/aqi_list_page.dart';
import 'package:flutter/material.dart';
import 'package:go_router/go_router.dart';
import 'package:amplify_authenticator/amplify_authenticator.dart';
import 'package:reaqtionsapplication/common/navigation/router/routes.dart';
import 'package:reaqtionsapplication/common/utils/colors.dart' as constants;

class ReAQtionsApp extends StatelessWidget {
  const ReAQtionsApp({
    required this.isAmplifySuccessfullyConfigured,
    Key? key,
  }) : super(key: key);

  final bool isAmplifySuccessfullyConfigured;

  @override
  Widget build(BuildContext context) {
    final router = GoRouter(
      routes: [
        GoRoute(
          path: '/',
          name: AppRoute.home.name,
          builder: (context, state) => isAmplifySuccessfullyConfigured
              ? const AQIListPage()
              : const Scaffold(
            body: Center(
              child: Text(
                'Tried to reconfigure Amplify; '
                    'this can occur when your app restarts on Android.',
              ),
            ),
          ),
        ),
      ],
      errorBuilder: (context, state) => Scaffold(
        body: Center(
          child: Text(state.error.toString()),
        ),
      ),
    );

    return Authenticator(
      child: MaterialApp.router(
        routeInformationParser: router.routeInformationParser,
        routeInformationProvider: router.routeInformationProvider,
        routerDelegate: router.routerDelegate,
        builder: Authenticator.builder(),
        theme: ThemeData(
          primarySwatch: constants.primaryColor,
          backgroundColor: const Color(0xff82CFEA),
        ),
      ),
    );
  }
}

Finally, here are the dependencies:

version: 1.0.0+1

environment:
  sdk: ">=2.18.4 <3.0.0"

dependencies:
  amplify_api: ^0.6.0
  amplify_auth_cognito: ^0.6.0
  amplify_authenticator: ^0.2.2
  amplify_datastore: ^0.6.0
  amplify_flutter: ^0.6.0
  amplify_storage_s3: ^0.6.0
  cached_network_image: ^3.2.1
  cupertino_icons: ^1.0.2
  flutter:
    sdk: flutter
  flutter_hooks: ^0.18.5+1
  flutter_riverpod: ^1.0.4
  go_router: ^4.1.0
  hooks_riverpod: ^1.0.4
  image_picker: ^0.8.5+3
  intl: ^0.17.0

dev_dependencies:
  flutter_lints: ^2.0.1
  flutter_test:
    sdk: flutter



flutter:
  uses-material-design: true
  plugin:
    platforms:
      android:
        package: io.github.edufolly.flutterbluetoothserial
        pluginClass: FlutterBluetoothSerialPlugin

Thanks so much

Originally posted by @nabram in #2551 (comment)

[ragingsquirrel3]

@nabram sorry you are having this issue with the tutorial. I could not reproduce this exception but I wanted to ask some followup questions to ensure I'm not missing something relevant:

• You mentioned you updated Android SDK. Could you please attach output of flutter doctor? That will indicate which version you are having this issue with.
• Could you please add source for 'package:reaqtionsapplication/features/airquality/ui/aqi_list/aqi_list_page.dart'; as not sure if this might have something relevant (doesn't seem likely).
• Could you attach the contents of your amplifyconfiguration.dart file with any API keys, user Pool IDs, resource identifiers etc... anonymized?
• At what point in tutorial did you have this issue?
• Is the source for your app available anywhere that we could use to repro? If not is ok, will continue trying to repro in same way.

[nabram]

Hi @ragingsquirrel3 - I just updated my flutter today. I tried running the program and still had issues. I've attached what you're looking for now.

1. Flutter doctor readout

Doctor summary (to see all details, run flutter doctor -v):
[√] Flutter (Channel stable, 3.3.10, on Microsoft Windows [Version 10.0.22621.1105], locale en-US)
[√] Android toolchain - develop for Android devices (Android SDK version 33.0.0)
[√] Chrome - develop for the web
[√] Visual Studio - develop for Windows (Visual Studio Build Tools 2019 16.11.17)
[√] Android Studio (version 2022.1)
[√] VS Code (version 1.74.3)
[√] Connected device (4 available)
[√] HTTP Host Availability

• No issues found!

2. AQI List

import 'package:flutter/material.dart';
import 'package:reaqtionsapplication/common/utils/colors.dart' as constants;

class AQIListPage extends StatelessWidget {
  const AQIListPage({
    super.key,
  });

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        centerTitle: true,
        title: const Text(
          'ReAQtions CanAIRy Pollutants',
        ),
        backgroundColor: const Color(constants.primaryColorDark),
      ),
      floatingActionButton: FloatingActionButton(
        onPressed: () {},
        backgroundColor: const Color(constants.primaryColorDark),
        child: const Icon(Icons.add),
      ),
      body: const Center(
        child: Text('Pollutant List'),
      ),
    );
  }
}

3. amplifyconfiguration.dart

const amplifyconfig = ''' {
    "UserAgent": "aws-amplify-cli/2.0",
    "Version": "1.0",
    "auth": {
        "plugins": {
            "awsCognitoAuthPlugin": {
                "UserAgent": "aws-amplify-cli/0.1.0",
                "Version": "0.1.0",
                "IdentityManager": {
                    "Default": {}
                },
                "CredentialsProvider": {
                    "CognitoIdentity": {
                        "Default": {
                            "PoolId": "pool id",
                            "Region": "us-east-1"
                        }
                    }
                },
                "CognitoUserPool": {
                    "Default": {
                        "PoolId": "pool id",
                        "AppClientId": "app id",
                        "Region": "us-east-1"
                    }
                },
                "Auth": {
                    "Default": {
                        "authenticationFlowType": "USER_SRP_AUTH",
                        "socialProviders": [],
                        "usernameAttributes": [
                            "EMAIL"
                        ],
                        "signupAttributes": [
                            "EMAIL"
                        ],
                        "passwordProtectionSettings": {
                            "passwordPolicyMinLength": 8,
                            "passwordPolicyCharacters": []
                        },
                        "mfaConfiguration": "OFF",
                        "mfaTypes": [
                            "SMS"
                        ],
                        "verificationMechanisms": [
                            "EMAIL"
                        ]
                    }
                }
            }
        }
    }
}''';

4. Module where the issue occurred###

I was at the end of module 2. I was trying to run test the authentication and received the error that the plugins were not added.

5. Source

It's currently not but if there's still issues, I'm happy to upload it to git

[Jordan-Nelson]

@nabram Based on the following two lines from the log:

I/flutter ( 7893): Amplify plugin was not added
E/flutter ( 7893): [ERROR:flutter/runtime/dart_vm_initializer.cc(41)] Unhandled Exception: AmplifyException(message: Amplify plugin AmplifyAuthCognitoMethodChannel was not added successfully., recoverySuggestion: We currently don't have a recovery suggestion for this exception., underlyingException: AmplifyException(message: MissingPluginException(No implementation found for method addPlugin on channel com.amazonaws.amplify/auth_cognito), recoverySuggestion: null, underlyingException: null))

The exception is being thrown when trying to add the Auth plugin. You can see where that log/exception comes from in Amplify below.

amplify-flutter/packages/amplify/amplify_flutter/lib/src/method_channel_amplify.dart

Lines 64 to 71 in 7bcaa09

	} on Exception catch (e) {
	safePrint('Amplify plugin was not added');
	throw AmplifyException(
	'Amplify plugin ${plugin.runtimeType} was not added successfully.',
	recoverySuggestion: AmplifyExceptionMessages.missingRecoverySuggestion,
	underlyingException: e.toString(),
	);
	}

I notice in the code you provided above, you have a try/catch around Amplify.addPlugins(), which prints, "Amplify configuration failed". I don't see that in your log output though. That would indicate that Amplify.addPlugins or Amplify.addPlugin is being called somewhere else in your app. Can you see if you have any calls to any of the following functions outside of the code you have provided?

• Amplify.addPlugins
• Amplify.addPlugin
• Amplify.configure
• _configureAmplify

[nabram]

I have the await Amplify.addPlugins function in the main.dart that I provided in the first question. I'll repaste the main.dart

import 'package:reaqtionsapplication/reaqtions_app.dart';
import 'package:flutter/material.dart';
import 'package:amplify_flutter/amplify_flutter.dart';
import 'package:amplify_auth_cognito/amplify_auth_cognito.dart';
import 'package:flutter_riverpod/flutter_riverpod.dart';
import 'amplifyconfiguration.dart';

Future<void> main() async {
  WidgetsFlutterBinding.ensureInitialized();
  bool isAmplifySuccessfullyConfigured = false;
  try {
    await _configureAmplify();
    isAmplifySuccessfullyConfigured = true;
  } on AmplifyAlreadyConfiguredException {
    debugPrint('Amplify configuration failed.');
  }

  runApp(
    ProviderScope(
      child: ReAQtionsApp(
        isAmplifySuccessfullyConfigured: isAmplifySuccessfullyConfigured,
      ),
    ),
  );
}

Future<void> _configureAmplify() async {
  await Amplify.addPlugins([ ///<==This is where I'm calling the addPlugins. 
    AmplifyAuthCognito(),
  ]);
  await Amplify.configure(amplifyconfig);
}

Edit: I'd also like to add that I did not have this issue until I updated Android SDK. I don't know if that has anything to do with it.

[Jordan-Nelson]

Hello @nabram - Can you let us know if you are still facing this issue? I think @ragingsquirrel3 had spent some time trying to reproduce this and was unsuccessful.

[Jordan-Nelson]

@nabram - I am going to close this out since I have not heard back. If you are still facing this issue, please let us know.