Internet.dart

// before rendering your main page use write a condition
var connectivityResult = await (Connectivity().checkConnectivity());
    if (connectivityResult == ConnectivityResult.mobile) {
    // this will show when your device is connected with mobile network
    print("connected to mobile data");
      // ignore: unused_local_variable
      ScaffoldMessenger.of(context).showSnackBar(
        SnackBar(
          content: const Text('Connected to mobile network'),
          backgroundColor: Colors.green,
        ),
      );
    else if(connectivityResult == ConnectivityResult.wifi){
    // this will show when your device is connected with wifi
    print("connected to wifi");
      ScaffoldMessenger.of(context).showSnackBar(
        SnackBar(
          content: const Text('Connected to wifi network '),
          backgroundColor: Colors.green,
        ),
      );
    }else {
    // This will shown when your device is disconnected 
      ScaffoldMessenger.of(context).showSnackBar(
        SnackBar(
          content: const Text('No internet connection'),
          backgroundColor: Colors.black,
          action: SnackBarAction(
            label: 'retry',
            onPressed: () {
              // Code to execute. or you can simply refresh your page you can also include an image
              setState(() {
              });
            },
          ),
        ),
      );
      print("No internet connection");
    }