Question

配置认证插件后运行Amplify Flutter tutorial项目时，不断收到如下错误：

Error: MissingPluginException(No implementation found for method configure on channel com.amazonaws.amplify/amplify)
    at Object.throw_ [as throw] (http://localhost:56261/dart_sdk.js:5331:11)
    at MethodChannel._invokeMethod (http://localhost:56261/packages/flutter/src/services/system_channels.dart.lib.js:954:21)
    at _invokeMethod.next (<anonymous>)
    at http://localhost:56261/dart_sdk.js:39029:33
    at _RootZone.runUnary (http://localhost:56261/dart_sdk.js:38886:58)
    at _FutureListener.thenAwait.handleValue (http://localhost:56261/dart_sdk.js:33872:29)
    at handleValueCallback (http://localhost:56261/dart_sdk.js:34432:49)
    at Function._propagateToListeners (http://localhost:56261/dart_sdk.js:34470:17)
    at _Future.new.[_completeWithValue] (http://localhost:56261/dart_sdk.js:34312:23)
    at async._AsyncCallbackEntry.new.callback (http://localhost:56261/dart_sdk.js:34335:35)
    at Object._microtaskLoop (http://localhost:56261/dart_sdk.js:39173:13)
    at _startMicrotaskLoop (http://localhost:56261/dart_sdk.js:39179:13)
    at http://localhost:56261/dart_sdk.js:34686:9

main.dart 中的以下代码直接从 Amplify Flutter 复制，但仅使用了 Auth 插件：

class _MyHomePageState extends State<MyHomePage> {
  @override
  initState() {
    super.initState();
    _configureAmplify();
  }

  void _configureAmplify() async {
    AmplifyAuthCognito authPlugin = AmplifyAuthCognito();
    Amplify.addPlugin(authPlugin);

    try {
      await Amplify.configure(amplifyconfig); # <--- this is what throws the MissingPluginException 
    } on AmplifyAlreadyConfiguredException {
      print(
          "Tried to reconfigure Amplify; this can occur when your app restarts on Android.");
    }
  }
...
}

pubspec.yaml:

name: <myproject>
description: <description>

version: 1.0.0+1

environment:
  sdk: ">=2.7.0 <3.0.0"

dependencies:
  flutter:
    sdk: flutter

  amplify_flutter: '<1.0.0'
  amplify_auth_cognito: '<1.0.0'

  cupertino_icons: ^1.0.2

dev_dependencies:
  flutter_test:
    sdk: flutter

flutter:
  uses-material-design: true

是的，是的，我已经搜索过 stackoverflow 和 github。我已经尝试了任何人建议的一切，包括：

关闭应用程序，运行 flutter clean 然后运行 flutter pub get
更新我的所有依赖项
缓存无效并重新启动 Android Studio
确保通过在 WidgetsFlutterBinding.ensureInitialized() 中调用 main() 来初始化小部件
确保在加载 Auth 插件之前我没有调用 Amplify.configure()
启动了一个全新的项目并重新初始化了 Amplify

Answer 1

截至发帖时，Amplify-Flutter 不支持 Web 平台，此错误在此之前是预期行为。请参阅：https://github.com/aws-amplify/amplify-flutter/issues/234

MissingPluginException（在频道 com.amazonaws.amplify/amplify 上找不到配置方法的实现）

1 个答案: