I created a form when user will put their revenue and the system will calculate the total revenue and store all the data in the database.

When I try submit the inputted data, I received code 400 (Exception: Bad request. Please check the submitted data.)

I want to pass the data using parameters. What is the error in this code?

setState(()  {
      String OccRoomText = _occRoomController.text;
      String ADRText = _adrController.text;
      String FnBRevenueText = _fnbrevenueController.text;
      String extraRevenueText = _extrarevenueController.text;      
      
      if (_formKey.currentState!.validate()) {
        print('2');
        String hotel = 'DTH';
        String date = _dateController.text;
        int totalroom = 299;
        double OccupiedRoom = double.parse(OccRoomText);
        double ADR = double.parse(ADRText);
        double FnBRevenue = double.parse(FnBRevenueText);
        double ExtraRevenue = double.parse(extraRevenueText);
        occRate = double.parse(((OccupiedRoom/totalroom)*100).toStringAsFixed(2));
        TotalRoomRevenue = double.parse((OccupiedRoom*ADR).toStringAsFixed(2));
        roomRevenue = formatter.format(TotalRoomRevenue.round());
        RevPAR = double.parse((TotalRoomRevenue/totalroom).toStringAsFixed(2));
        TotalFnBRevenue = double.parse((FnBRevenue + ExtraRevenue).toString());
        int FNBRevenue = TotalFnBRevenue.round();
        TotalRevenue = formatter.format((TotalRoomRevenue + FNBRevenue).round());

        print(TotalRevenue);
        Future<http.Response> submitform() async {
          print('ready');
          final response = await http.post(
            Uri.parse('http://xxxx/xxxx/api/hotel/InsertHotelDailyRevenue?hotel=$hotel&RptDate=$date&TotalRooms=<span class="math-inline">totalroom&OccupiedRooms=</span>{OccupiedRoom.toStringAsFixed(2)}&OccupancyRate=$occRate&ADR=</span>{ADR.toStringAsFixed(2)}&RevPAR=$RevPAR&TotalRoomRevenue=$roomRevenue&TotalFnBRevenue=<span class="math-inline">FNBRevenue&TotalRevenue=$TotalRevenue'), // Use toStringAsFixed for double values
            headers: <String, String>{
              'Content-Type': 'application/x-www-form-urlencoded', // Adjust if needed
            },
          );
          print('after api');

          if (response.statusCode == 201) {
            print('201');
            ScaffoldMessenger.of(context).showSnackBar(
              SnackBar(content: Text('Data submitted successfully!')),
            );
          } else {
            String errorMessage = 'Failed to submit data.';
            switch (response.statusCode) {
              case 400:
                errorMessage = 'Bad request. Please check the submitted data.';
                break;
              case 401:
                errorMessage = 'Unauthorized. Please check your credentials.';
                break;
              case 403:
                errorMessage = 'Forbidden. You are not authorized to submit data.';
                break;
              default:
                errorMessage = 'Error: ${response.statusCode}';
            }
            throw Exception(errorMessage);
          }
          return response;
        }

        Future<http.Response> response = submitform();
        response.then((value) => {
          // Handle the response here (e.g., check status code, parse data)
          print(value.statusCode)// Print the status code
        }).catchError((error) => {
          // Handle errors here
          print(error)
        });