flutter - 互联网连接困惑

Question

如何在整个应用程序中仅一次执行连续的Internet连接检查，我已经完成了几乎完整的应用程序，现在我需要添加Internet连接检查，请帮助，在此先感谢

  @override
  Widget build(BuildContext context) {
      return StreamBuilder<ConnectivityResult>(
          stream: connectivityStream,
          builder: (context, snapshot) {
            if (snapshot.hasData) {
              final connectivityResult = snapshot.data;
              if (connectivityResult == ConnectivityResult.none) {
                return MaterialApp(
                  debugShowCheckedModeBanner: false,
                  home: NoInternetConnectionScreen(),
                );
              }
              return MaterialApp(
                debugShowCheckedModeBanner: false,
                home: SplashScreen(),
                routes: routes,
              );

            } else if (snapshot.hasError) {

              return MaterialApp(
                debugShowCheckedModeBanner: false,
                home: NoInternetConnectionScreen(),
              );
            }

            return Center(child: CircularProgressIndicator());
          }
      );
  }

Answer 1

连接插件在其文档中指出，仅在存在网络连接时提供信息，而在网络连接到Internet时不提供信息

Note that on Android, this does not guarantee connection to Internet. For instance, the app might have wifi access but it might be a VPN or a hotel WiFi with no access.

您可以使用

import 'dart:io';
...
try {
  final result = await InternetAddress.lookup('google.com');
  if (result.isNotEmpty && result[0].rawAddress.isNotEmpty) {
    print('connected');
  }
} on SocketException catch (_) {
  print('not connected');
}