Using structs with TextField

Question

Created Jun ’22

Replies 1

Boosts 0

Participants 2

New to Swift and am trying to use structs where I can hold values. When I try to bind them with a TextField it doesn't update the actual variable. What is wrong?

   
   
  @State var final = finalBluePrint()
   
  var body : some View {
     
    NavigationView {
    
         
        VStack {
           
          TextField("Current Grade", value: $final.currentGrade, format: .number).keyboardType(.decimalPad);
           
          TextField("Desired Grade", value: $final.desiredGrade, format: .number).keyboardType(.decimalPad);
           
           
          TextField("Final Weight", value: $final.finalWeight, format: .number).keyboardType(.decimalPad);
           
           
          Text(final.currentGrade, format: .number);
           
           
           
          Text(final.finalNeededGrade, format: .number);
        }

   
  @State var currentGrade: Double = 5;
  @State var desiredGrade : Double = 0;
  @State var finalWeight : Double = 0;


   
   
   
   
  var finalNeededGrade : Double {
     
    let desiredGrade = self.desiredGrade;
    let currentGrade = self.currentGrade;
    let finalWeight = self.finalWeight;
     
    let finalNeededGrade = (desiredGrade - currentGrade * (100 - finalWeight)) / finalWeight;

     
    return finalNeededGrade
     
  }

Thank you!

Answered by zunda in 717502022

class FinalBluePrint: ObservableObject {
 @Published var currentGrade: Double = 5;
 @Published var desiredGrade : Double = 0;
 @Published var finalWeight : Double = 0;

 var finalNeededGrade : Double {

  let desiredGrade = self.desiredGrade;
  let currentGrade = self.currentGrade;
  let finalWeight = self.finalWeight;

  let finalNeededGrade = (desiredGrade - currentGrade * (100 - finalWeight)) / finalWeight;


  return finalNeededGrade

 }
}

struct ContentView: View {
 @StateObject var final = FinalBluePrint()

 var body : some View {
  NavigationView {
   VStack {
    TextField("Current Grade", value: $final.currentGrade, format: .number).keyboardType(.decimalPad);
    TextField("Desired Grade", value: $final.desiredGrade, format: .number).keyboardType(.decimalPad);
    TextField("Final Weight", value: $final.finalWeight, format: .number).keyboardType(.decimalPad);
    Text(final.currentGrade, format: .number);
    Text(final.finalNeededGrade, format: .number);
   }
  }
 }
}

Boost

Answer 1

zunda OP

Jun ’22

Accepted Answer

class FinalBluePrint: ObservableObject {
 @Published var currentGrade: Double = 5;
 @Published var desiredGrade : Double = 0;
 @Published var finalWeight : Double = 0;

 var finalNeededGrade : Double {

  let desiredGrade = self.desiredGrade;
  let currentGrade = self.currentGrade;
  let finalWeight = self.finalWeight;

  let finalNeededGrade = (desiredGrade - currentGrade * (100 - finalWeight)) / finalWeight;


  return finalNeededGrade

 }
}

struct ContentView: View {
 @StateObject var final = FinalBluePrint()

 var body : some View {
  NavigationView {
   VStack {
    TextField("Current Grade", value: $final.currentGrade, format: .number).keyboardType(.decimalPad);
    TextField("Desired Grade", value: $final.desiredGrade, format: .number).keyboardType(.decimalPad);
    TextField("Final Weight", value: $final.finalWeight, format: .number).keyboardType(.decimalPad);
    Text(final.currentGrade, format: .number);
    Text(final.finalNeededGrade, format: .number);
   }
  }
 }
}

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