我有一个网站，我转换到Flutter Android应用程序的网站使用webview_flutter插件，一切都工作正常.
但是有一个问题，网站上有一个表格，表格中有一个文件输入。在网站上一切正常，但当我点击上传文件从Android应用程序，我使用webview_flutter插件创建，文件输入不工作。
当我点击上传文件，它不会打开任何弹出窗口或任何东西，让我选择文件从我的手机，并上传到表格。
这是我的主要.dart代码：

import 'package:flutter/material.dart';
import 'package:permission_handler/permission_handler.dart';
import 'package:webview_flutter/webview_flutter.dart';
import 'package:custom_splash/custom_splash.dart';
import 'package:connectivity/connectivity.dart';
import 'package:selfcare/nointernet.dart';

void main() {

  WidgetsFlutterBinding.ensureInitialized();
  runApp(MyApp());

}

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
        title: "Self Care",
        debugShowCheckedModeBanner: false,
        theme: ThemeData(
          primarySwatch: Colors.red,
        ),
        home: Scaffold(body: splash()));
  }
}

class splash extends StatefulWidget {
  @override
  _splashState createState() => _splashState();
}

class _splashState extends State<splash> {
  String result = '';
  var Colorsval = Colors.white;

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

  @override
  Widget build(BuildContext context) {
    if (result != null && result == "Connected") {
      return CustomSplash(
        //backGroundColor: Color(0xFFFF9800),
        imagePath: "assets/images/logo.png",

        home: WebViewClass(),
        duration: 10,
        animationEffect: "zoom-in",
      );
    } else if (result != null && result == "NoInternet") {
      return CustomSplash(
        //backGroundColor: Color(0xFFFF9800),
        imagePath: "assets/images/logo.png",

        home: NoInternetPage(),
        duration: 10,
        animationEffect: "zoom-in",
      );
    } else if (result == null) {
      return CustomSplash(
        //backGroundColor: Color(0xFFFF9800),
        imagePath: "assets/images/logo.png",

        home: NoInternetPage(),
        duration: 10,
        animationEffect: "zoom-in",
      );
    } else {
      return CustomSplash(
        //backGroundColor: Color(0xFFFF9800),
        imagePath: "assets/images/logo.png",

        home: NoInternetPage(),
        duration: 10,
        animationEffect: "zoom-in",
      );
    }
  }

  void CheckStatus() {
    Connectivity().onConnectivityChanged.listen((ConnectivityResult result) {
      if (result == ConnectivityResult.mobile ||
          result == ConnectivityResult.wifi) {
        ChangeValues("Connected", Colors.green[900]);
      } else {
        ChangeValues("NoInternet", Colors.red[900]);
      }
    });
  }

  void ChangeValues(String resultval, Color colorval) {
    setState(() {
      result = resultval;
      Colorsval = colorval;
    });
  }
}

class WebViewClass extends StatefulWidget {
  WebViewState createState() => WebViewState();
}

class WebViewState extends State<WebViewClass> {
  num position = 1;

  final key = UniqueKey();

  doneLoading(String A) {
    setState(() {
      position = 0;
    });
  }

  startLoading(String A) {
    setState(() {
      position = 1;
    });
  }

  @override
  void initState() {
    // TODO: implement initState
    super.initState();
    Permission.mediaLibrary.request();
    Permission.phone.request();
    Permission.photos.request();
    Permission.storage.request();
    Permission.camera.request();
  }
  //Check Internet Code Starts

  //Check Internet Code Ended here
  @override
  Widget build(BuildContext context) {
    return Scaffold(
        //appBar: AppBar(title: Text('Show ProgressBar While Loading Webview')),
        appBar: PreferredSize(
          child: Container(),
          preferredSize: Size.fromHeight(0.0),
        ),
        body: IndexedStack(index: position, children: <Widget>[
          WebView(
            initialUrl: 'http://mywebsite.com',
            javascriptMode: JavascriptMode.unrestricted,
            key: key,
            onPageFinished: doneLoading,
            onPageStarted: startLoading,
            //onWebResourceError: ,
          ),
          Container(
            color: Colors.white,
            child: Center(
                child: CircularProgressIndicator(
              valueColor: new AlwaysStoppedAnimation<Color>(Colors.red),
            )),
          ),
        ]));
  }
}

这是我使用的flutter webview插件：

dependencies:
  webview_flutter: ^1.0.7

我也使用了一些权限来摆脱这个问题，但没有解决它，权限：

Permission.mediaLibrary.request();
Permission.phone.request();
Permission.photos.request();
Permission.storage.request();
Permission.camera.request();