Flutter double value calculation errors-CodePudding

I am a Beginner and I want to calculate 4 values and get area but I keep getting different errors my code is not good so please give advices Like: Class 'String' has no instance method '/'. Receiver: "56" Tried calling: /(2) I am taking values from text fields I want them to be calculated in double.

This is My Code ` class SideController extends GetxController{

  final SideAController = TextEditingController();
  final SideBController = TextEditingController();
  final SideCController = TextEditingController();    
  final SideDController = TextEditingController();
  var Result=''.obs;
  var sidea;
  var sideb;
  var sidec;
  var sided;
  var length;
  var width;
  var area = 0.obs;

  calculateheight() {
    if (SideAController.text != null ||
        SideBController.text != null ||
        SideCController.text != null ||
        SideDController.text != null) {
      sidea = SideAController.text;
      sideb = SideBController.text;
      sidec = SideCController.text;
      sided = SideDController.text;

      length = ((sidea)   (sidec)) / 2;
      width = ((sideb)   (sided)) / 2;

      area = (length * width);
      area.value == Result;
      return area;
    } else {
      Get.snackbar("Fields Empty", "Fill all Fields");
    }
  }
}

I tried to calculate 4 values and show my result is string but keep getting errors

CodePudding user response：

String values cannot be added or divided. You have to convert the String values to double first.

 sidea = double.parse(SideAController.text);
 sideb = double.parse(SideBController.text);
 sidec = double.parse(SideCController.text);
 sided = double.parse(SideDController.text);

 length = ((sidea)   (sidec)) / 2;
 width = ((sideb)   (sided)) / 2;

 area.value = (length * width);
 // area.value == Result;
 return area;

If you want to return area as String, use return area.toString();

CodePudding user response：

I think there are already variables here. I write down what I already know. For example, there is Result=''.obs;

class SideController extends GetxController {
  final SideAController = TextEditingController();
  final SideBController = TextEditingController();
  final SideCController = TextEditingController();
  final SideDController = TextEditingController();

  var sidea;
  var sideb;
  var sidec;
  var sided;
  var length;
  var width;
  RxDouble area = 0.0.obs;

  dynamic calculateheight() {
    if (SideAController.text.isNotEmpty &&
        SideBController.text.isNotEmpty &&
        SideCController.text.isNotEmpty &&
        SideDController.text.isNotEmpty) {
      sidea = double.parse(SideAController.text);
      sideb = double.parse(SideBController.text);
      sidec = double.parse(SideCController.text);
      sided = double.parse(SideDController.text);
      length = (sidea   sidec) / 2;
      width = (sideb   sided) / 2;
      area.value = length * width;
      return area.value.toString();
    } else {
      Get.snackbar("Fields Empty", "Fill all Fields");
      return ' error';
    }
  }
}

I checked the code I posted, the code I posted should work for you. Optionally, calculateheight() function can return String, double, etc.