在学习 Flutter，被一个问题折腾了好几天了，问题简化如下：

Flutter 版本是 v1.17.0；

现有 Android 工程，里面有两个 Activity：

1. MainActivity，该 Activity 中有一个按钮
2. NativeActivity 。

然后又按照官方文档集成了 Flutter module，里面有页面 FlutterRoute，FlutterRoute 中有一个按钮。

现在操作逻辑如下： 点击 MainActivity 中的按钮，跳转到 Flutter 页面，然后点击 FlutterRoute 中的按钮，再跳转到 NativeActivity 。

现在 MainActivity 代码如下：

import android.content.Intent; import android.os.Bundle; import android.view.View; import android.widget.Button;  import androidx.annotation.NonNull;  import io.flutter.embedding.android.FlutterActivity; import io.flutter.embedding.engine.FlutterEngine; import io.flutter.plugin.common.MethodCall; import io.flutter.plugin.common.MethodChannel; import io.flutter.plugins.GeneratedPluginRegistrant;   public class MainActivity extends FlutterActivity implements View.OnClickListener, MethodChannel.MethodCallHandler {      private Button button;     private static final String CHANNEL_NAME = "TEST_CHANNEL_NAME";     private MethodChannel channel;       @Override     protected void onCreate(Bundle savedInstanceState) {         super.onCreate(savedInstanceState);         setContentView(R.layout.activity_main);         button = findViewById(R.id.button);         button.setOnClickListener(this);       }      @Override     public void configureFlutterEngine(@NonNull FlutterEngine flutterEngine) {         super.configureFlutterEngine(flutterEngine);         GeneratedPluginRegistrant.registerWith(flutterEngine);         channel = new MethodChannel(flutterEngine.getDartExecutor().getBinaryMessenger(), CHANNEL_NAME);         channel.setMethodCallHandler(this);     }      @Override     public void onClick(View v) {         startActivity(                 FlutterActivity.withNewEngine().build(this)         );     }       @Override     public void onMethodCall(@NonNull MethodCall methodCall, @NonNull MethodChannel.Result result) {         if ("startNativeActivity".equals(methodCall.method)) {             Intent intent = new Intent(MainActivity.this, NativeActivity.class);             startActivity(intent);         }     } } 

Flutter 代码如下：

import 'package:flutter/cupertino.dart'; import 'package:flutter/material.dart'; import 'package:flutter/services.dart';  void main(){   runApp(       MaterialApp(         routes: {           "/":(BuildContext context)=>FlutterRoute(),         },         initialRoute: "/",       )   ); }  class FlutterRoute extends StatefulWidget {   FlutterRouteState createState() {     return FlutterRouteState();   } }  class FlutterRouteState extends State<FlutterRoute> {    static const channel = MethodChannel("TEST_CHANNEL_NAME");    Future<void> startNativeActivity() async{     await channel.invokeMethod("startNativeActivity");   }    @override   Widget build(BuildContext context) {     return Scaffold(       appBar: AppBar(         title: Text("Flutter 页面"),       ),       body: Container(         color: Colors.lightGreenAccent,         child: Center(           child: Column(             children: <Widget>[               Text("Flutter 页面"),               MaterialButton(                 color: Colors.redAccent,                 child: Text("跳转到原生 Activity"),                 onPressed: () {                   startNativeActivity();                 },               ),             ],           ),         ),       ),     );   } } 

在 MainActivity 中点击按钮，可以跳转到 FlutterRoute，但是在 FlutterRoute 中点击按钮跳转到 NativeActivity 的时候却抛出：

E/flutter: [ERROR:flutter/lib/ui/ui_dart_state.cc(157)] Unhandled Exception: MissingPluginException(No implementation found for method startNativeActivity on channel TEST_CHANNEL_NAME)     #0      MethodChannel._invokeMethod (package:flutter/src/services/platform_channel.dart:154:7)     <asynchronous suspension>     #1      MethodChannel.invokeMethod (package:flutter/src/services/platform_channel.dart:329:12)     #2      FlutterRouteState.startNativeActivity (package:fluttermodule/main.dart:27:19)     #3      FlutterRouteState.build.<anonymous closure> (package:fluttermodule/main.dart:46:19)     #4      _InkResponseState._handleTap (package:flutter/src/material/ink_well.dart:779:19)     #5      _InkResponseState.build.<anonymous closure> (package:flutter/src/material/ink_well.dart:862:36)     #6      GestureRecognizer.invokeCallback (package:flutter/src/gestures/recognizer.dart:182:24)     #7      TapGestureRecognizer.handleTapUp (package:flutter/src/gestures/tap.dart:504:11)     #8      BaseTapGestureRecognizer._checkUp (package:flutter/src/gestures/tap.dart:282:5)     ...... 

究竟是哪里出了问题啊，折腾好几天了，始终不行，难道 MethodChannel 不是这么用的吗？

百度谷歌官方 githubStackOverflow 搜了个遍。。。

实在没辙了，求点醒求指教，感谢