homepage.dart

 late StreamSubscription subscription;
  bool isDeviceConnected = false;
  bool isAlertSet = false;

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

  getConnectivity() =>
      subscription = Connectivity().onConnectivityChanged.listen(
        (ConnectivityResult result) async {
          isDeviceConnected = await InternetConnectionChecker().hasConnection;
          if (!isDeviceConnected && isAlertSet == false) {
            showDialogBox();
            setState(() => isAlertSet = true);
          }
        },
      );

  @override
  void dispose() {
    subscription.cancel();
    super.dispose();
  }