Android 在Flatter WebView中检查连接并强制刷新

我还是个新手，还没开始尝试一些新东西。我正在继续我的Flitter

WebView

personal project应用程序。它有5个选项卡，每个选项卡在脚手架中包含一个WebView。我想要的是：

检测用户点击选项卡（例如：主页）的时间，然后将其保存到

变量中

保存后，用户退出主页选项卡并重新进入时，应用程序将通过与

变量中存储的时间进行比较，检查用户离开选项卡的时间是否超过1分钟
如果超过1分钟：

检查连接

如果连接可用，则对WebView执行强制刷新
如果没有可用的连接，则显示一个对话框，说明“无连接”
如果不超过1分钟：

应用程序将继续，不会调用任何内容

到目前为止我试过的是

var lastloaded                  //the variable where the access time of the tab will be saved

  void tappingOnTab() {         //the function that will store that data and check if its > 1 min
    final now = DateTime.now();
    if(lastloaded != null){
      if(now.difference(lastloaded).inMinutes > 1) {
        _checkConnection();
      }
    lastloaded = now;
    }
  }


  _checkConnection() async {      //the function that will check for connection if its greater than 1 min
    var result = await (Connectivity().checkConnectivity());
    if(result == ConnectivityResult.none) {
      _showDialog("No internet", "You are not connected to the internet");
    } else if (result == ConnectivityResult.mobile) {
      _showDialog("Internet Access", "You are connected over mobile data");
    } else if (result == ConnectivityResult.wifi) {
      _showDialog("Internet Access", "You are connected over wifi");
    }
  }

  _showDialog(title, text) {
    showDialog(
      context: context,
      builder: (context) {
        return AlertDialog(
          title: Text(title),
          content: Text(text),
          actions: <Widget>[
            FlatButton(
              child: Text("Ok"),
              onPressed: () {
                Navigator.of(context).pop();
              },
            )
          ],
        );
      }
    );
  }
}

---

您应该能够在AlertDialog中的相同onPressed方法上使用控制器刷新WebView。

import 'dart:async';
import 'dart:io';
import 'package:firebase_messaging/firebase_messaging.dart';
import 'package:flutter/material.dart';
import 'package:syncshop_webview/widgets/notification_widget.dart';
import 'package:webview_flutter/webview_flutter.dart';
import 'package:connectivity/connectivity.dart';


class HomePage extends StatefulWidget {
  // HomePage({Key key}) : super(key: key);

  @override
  _HomePageState createState() => _HomePageState();
}

class _HomePageState extends State<HomePage> {
  final FirebaseMessaging _firebaseMessaging = FirebaseMessaging();
  // WebViewController myController;
  final flutterWebviewPlugin = new WebView();
var lastloaded;

  _exitApp(BuildContext context, Future<WebViewController> controller) async {
    controller.then((data) async {
      WebViewController controller = data;
      var goBack = await controller.canGoBack();
      if (goBack == true) {
        print("onwill go back");
        controller.goBack();
      } else {
        print("onwill not go back");
        Navigator.pop(context);
      }
    });
  }

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

  void firebaseCloudMessagingListeners() {
    if (Platform.isIOS) iOSPermission();

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

    _firebaseMessaging.configure(
      onMessage: (Map<String, dynamic> message) async {
        setState(() {
          print("${message['data']['url']}");
          Navigator.push(
              context,
              MaterialPageRoute(
                  builder: (BuildContext context) => NotificationClicked()));
        });
      },
      onResume: (Map<String, dynamic> message) async {
        print("${message['data']['url']}");
      },
      onLaunch: (Map<String, dynamic> message) async {
        print("${message['data']['url']}");
      },
    );
  }

  void iOSPermission() {
    _firebaseMessaging.requestNotificationPermissions(
        IosNotificationSettings(sound: true, badge: true, alert: true));
    _firebaseMessaging.onIosSettingsRegistered
        .listen((IosNotificationSettings settings) {
      print("Settings registered: $settings");
    });
  }



  Completer<WebViewController> _controller = Completer<WebViewController>();

  void tappingOnTab() {
    final now = DateTime.now();
    if(lastloaded != null){
      if(now.difference(lastloaded).inMinutes > 1) {
        _checkConnection();
      }
    lastloaded = now;
    }
  }

  @override
  Widget build(BuildContext context) {
    return WillPopScope(
        onWillPop: () => _exitApp(context, _controller.future),
        child: SafeArea(
    child: Scaffold(
        body: WebView(
    initialUrl: 'https://syncshop.online/en/',
    javascriptMode: JavascriptMode.unrestricted,
    onWebViewCreated: (controller) {
    _controller.complete(controller);
    },
    onPageFinished: (controller) async {
      //SOME INJECTION OF CODE HERE
    },
          ),
      //floating action button here
      ),
        ),
      );
  }
  _checkConnection() async {
    var result = await (Connectivity().checkConnectivity());
    if(result == ConnectivityResult.none) {
      _showDialog("No internet", "You are not connected to the internet");
    } else if (result == ConnectivityResult.mobile) {
      _showDialog("Internet Access", "You are connected over mobile data");
    } else if (result == ConnectivityResult.wifi) {
      _showDialog("Internet Access", "You are connected over wifi");
    }
  }

  _showDialog(title, text) {
    showDialog(
      context: context,
      builder: (context) {
        return AlertDialog(
          title: Text(title),
          content: Text(text),
          actions: <Widget>[
            FlatButton(
              child: Text("Ok"),
              onPressed: () {
                Navigator.of(context).pop();
              },
            )
          ],
        );
      }
    );
  }
}