Flutter: How can I add network check and showDialog on a Future function

I have below 2 methods in my Utility class: One for checking the network connection and on for showing the progress dialog.

static Future<bool> isInternet() async
  {
	bool result = await InternetConnectionChecker().hasConnection;
	return result;
  }

  static ShowProgress(BuildContext context) {
	return showDialog(
		context: context,
		barrierDismissible: false,
		builder: (BuildContext context) {
		  return Center(
			child: SpinKitRotatingCircle(color: const Color(0xff2799fa), size: 60.0, ),
		  );
		});
  }

I need to apply it on the below API call section:

class _UserDetailsState extends State<UserDetails> {
  ProfileResponse? profileResponse;
  Future<void> fetchData() async {
	try {
	  //Utility.ShowProgress(context);
	  final response = await getProfileDetails();
	  if (response.statusCode == 200) {
		Map<String, dynamic> parsedData = jsonDecode(response.body);
		setState(() {
		  profileResponse = ProfileResponse.fromJson(parsedData);
		});
	  } else {
		// setState(() {
		//   _data = 'Error: ${response.statusCode}';
		// });
	  }
	} catch (error) {
	  // setState(() {
	  //   _data = 'Error: $error';
	  // });
	}
	//Navigator.of(context).pop();
  }

  @override
  void initState() {
	fetchData();
  }
  
  @override
Widget build(BuildContext context) {
return Container(
     )
}
  
  Future<http.Response> getProfileDetails() async{
	if(await Utility.isInternet()){
	final SharedPreferences prefs = await SharedPreferences.getInstance();
	//reading values from SharedPreferences and calling the API
	final String url = My API Path;
	final response = await http.get(Uri.parse(url));
	return response;
	}
	else{
	  //show no network alert
	}
}

I added ProgressDialog in the fetchData(), like the commented code in the code, but it is not showing in the UI when calling the API.

Also I have added the network check on the getProfileDetails(), but it is showing below error.

> The body might complete normally, causing 'null' to be returned, but the return type, 'FutureOr<Response>', is a potentially non-nullable type. Try adding either a return or a throw statement at the end.

How can I fix these 2 issues?

Whenever you define a method that has some sort of expected output, your code should return the exact same type you defined or an error.

In your code you have declared a Future like this:

 Future<http.Response> getProfileDetails() async{

You should always return a Future<http.Response>.
However, when the first If condition is not True, there is nothing to be returned, resulting in your error.

The fixed code with progress dialog and network check adding below:

Future<http.Response?> getProfileDetails() async
{
	if(await Utility.isInternet())
	{
	  Utility.ShowProgress(context);
	  //reading values from SharedPreferences and calling the API
	  final String url = My API Path;
	  final response = await http.get(Uri.parse(url));
	  Navigator.of(context).pop();
	  return response;
	}
	else
	{
	  Utility.showToastMessage("No internet connection!",Toast.LENGTH_SHORT,
		  ToastGravity.CENTER, Colors.white, 16.0 );
	  return null;
	}
}