flutter 无法从H5 WebView 访问摄像头和录音权限

AndroidManifest.xml需要在 中添加以下权限：

<uses-permission android:name="android.permission.INTERNET"/><uses-permission android:name="android.permission.CAMERA"/><uses-permission android:name="android.permission.RECORD_AUDIO"/><uses-permission android:name="android.permission.MODIFY_AUDIO_SETTINGS"/><uses-permission android:name="android.permission.VIDEO_CAPTURE"/><uses-permission android:name="android.permission.AUDIO_CAPTURE"/>

import 'dart:async';
import 'package:flutter/material.dart';
import 'package:flutter_inappwebview/flutter_inappwebview.dart';
import 'package:permission_handler/permission_handler.dart';
Future main() async {
  WidgetsFlutterBinding.ensureInitialized();
  await Permission.camera.request();
  await Permission.microphone.request();runApp(MyApp());}
class MyApp extends StatefulWidget {
  @override
  _MyAppState createState()=> new _MyAppState();}
class _MyAppState extends State<MyApp>{
  @override
  Widget build(BuildContext context){returnMaterialApp(
        home:InAppWebViewPage());}}
class InAppWebViewPage extends StatefulWidget {
  @override
  _InAppWebViewPageState createState()=> new _InAppWebViewPageState();}
class _InAppWebViewPageState extends State<InAppWebViewPage>{
  InAppWebViewController _webViewController;
  @override
  Widget build(BuildContext context){returnScaffold(
        appBar:AppBar(
            title:Text("InAppWebView")),
        body:Container(
            child:Column(children:<Widget>[Expanded(
                child:Container(
                  child:InAppWebView(
                      initialUrlRequest:URLRequest(url: Uri.parse('url')),
                      initialOptions:InAppWebViewGroupOptions(
                        crossPlatform:InAppWebViewOptions(
                          mediaPlaybackRequiresUserGesture: false,
                          debuggingEnabled: true,),),
                      onWebViewCreated:(InAppWebViewController controller){
                        _webViewController = controller;},
                      androidOnPermissionRequest:(InAppWebViewController controller, String origin, List<String> resources) async {returnPermissionRequestResponse(resources: resources, action: PermissionRequestResponseAction.GRANT);//主要是这行代码是授权的}),),),])));}}