未处理的异常:MissingPluginException(没有在通道plugins.fltter.io/firebase_messaging上找到方法getToken的实现)

Question

我试图在我的应用程序中获得一个防火墙云消息传递令牌。在android仿真器上运行的是什么地方出了问题？我尝试了flutter run，但这不起作用，这里我使用了1.firebase_messaging：^6.0.9作为依赖项和2.

    import 'package:flutter/material.dart';
import 'package:firebase_messaging/firebase_messaging.dart';

class Notifications_ extends StatefulWidget {
  @override
  _Notifications_State createState() => _Notifications_State();
}

class _Notifications_State extends State<Notifications_> {

  final FirebaseMessaging _messaging=FirebaseMessaging();

  @override
  void initState() {
    super.initState();

    _messaging.getToken().then((token)
    {
      print(token);
    });

  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text('notification'),
      ),
      body: Text('body testing'),
    );
  }
}

E/flutter ( 5931)：错误:flutter/lib/ui/ui_dart_state.cc(157)未处理的异常:MissingPluginException(在通道plugins.flutter.io/firebase_messaging上未找到方法getToken的实现) E/ MethodChannel.invokeMethod (5 931)：#0 MethodChannel.invokeMethod MethodChannel.invokeMethod E/颤振(5 931)：E/颤振(5 931)：#1 FirebaseMessaging.getToken FirebaseMessaging.getToken E/颤振(5 931)：#2 _Notifications_State.initState (软件包:sampletestingpro/Notification)E/ (package:flutter/src/widgets/framework.dart:4201:5) ( 5931)：#3 StatefulElement._firstBuild StatefulElement._firstBuild E/.dart:17:16( 5931)：#4 ComponentElement.mount Element.inflateWidget E/flutter ( 5931)：#5 Element.inflateWidget(软件包:flutter/src/widget/Frawork.dart):3194:14) E/颤振( 5931)：#6 (package:flutter/src/widgets/framework.dart:2988:12) E/颤振(5 931)：#7 ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:4243:16) E/颤振(5 931)：#8 Element.rebuild (package:flutter/src/widgets/framework.dart:3947：5) E/颤振(5 931)：#9 (package:flutter/src/widgets/framework.dart:4298:5) E/颤振(5 931)：#10 Element.updateChild (package:flutter/src/widgets/framework.dart:2977:15) E/颤振(5 931)：#11 ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:4243:16)E/颤振( 5931)：#12 (package:flutter/src/widgets/framework.dart:3947:5) E/颤振( 5931)：#13 StatelessElement.update (package:flutter/src/widgets/framework.dart:4298:5) E/颤振( 5931)：#14 Element.updateChild (package:flutter/src/widgets/framework.dart:2977:15)E/颤振(5 931)：#15 (package:flutter/src/widgets/framework.dart:4243:16) E/颤振(5 931)：#16 Element.rebuild (package:flutter/src/widgets/framework.dart:3947:5) E/颤振(5 931)：#17 ProxyElement.update (package:flutter/src/widgets/framework.dart:4557:5)E/颤振(5 931)：#18 (package:flutter/src/widgets/framework.dart:2977:15) E/颤振(5 931)：#19 ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:4243:16) E/颤振(5 931)：#20 Element.rebuild (package:flutter/src/widgets/framework.dart:3947:5) E/颤振( 5931)：#21 (package:flutter/src/widgets/framework.dart:4557:5) E/颤振( 5931)：#22 Element.updateChild (package:flutter/src/widgets/framework.dart:2977:15) E/颤振( 5931)：#23 RenderObjectElement.updateChildren (package:flutter/src/widgets/framework.dart:5161:32) E/颤振( 5931)#24 (package:flutter/src/widgets/framework.dart:5561:17) E/颤振( 5931)：#25 Element.updateChild (package:flutter/src/widgets/framework.dart:2977:15) E/颤振( 5931)：#26 ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:4243:16) E/颤振( 5931)：#27 (package:flutter/src/widgets/framework.dart:3947:5) E/颤振( 5931)：#28 StatefulElement.update (package:flutter/src/widgets/framework.dart:4413:5) E/颤振( 5931)：#29 Element.updateChild (package:flutter/src/widgets/framework.dart:2977:15) E/颤振( 5931)：#30(package:flutter/src/widgets/framework.dart:4243:16) E/颤振( 5931)：#31 Element.rebuild (package:flutter/src/widgets/framework.dart:3947:5) E/颤振( 5931)：#32 ProxyElement.update (package:flutter/src/widgets/framework.dart:4557:5) E/颤振( 5931)：#33 Element.updateChild(package:flutter/src/widgets/framework.dart:2977:15) E/颤振( 5931)：#34 ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:4243:16) E/颤振( 5931)：#35 Element.rebuild (package:flutter/src/widgets/framework.dart:3947:5) E/颤振( 5931)：#36 StatefulElement.update (包装：5931:4413:5)E/ Element.updateChild ( 5931)：#37 Element.updateChild Element.updateChild E/颤振( 5931)：#38 SingleChildRenderObjectElement.update SingleChildRenderObjectElement.update E/flutter ( 5931)：#39 Element.updateChild(软件包:Element.updateChild/src)/widgets/Frawork.DART:2977:15)E/ ComponentElement.performRebuild ( 5931)：#40 ComponentElement.performRebuild ComponentElement.performRebuild E/ComponentElement.performRebuild( 5931)：#41 Element.rebuild Element.rebuild E/flutter ( 5931)：#42 StatelessElement.update (包:ComponentElement.performRebuild/src/widget/(5 931)：#43 (package:flutter/src/widgets/framework.dart:2977:15) E/ Element.updateChild (5 931)：#44 SingleChildRenderObjectElement.update (package:flutter/src/widgets/framework.dart:5452:14) E/颤振(5 931)：#45 Element.update。

Answer 1

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将google服务文件保存在应用程序文件夹中，我错误地将JSON文件放在src/文件夹中，这就是我得到错误的原因

Answer 2

所以，在尝试了许多解决方案后，这对我来说是有效的！

背景