I am currently learning about concurrency and would like to apply this knowledge to a basic calculation app I am developing. My goal is to ensure that two input calculation results are updated in real time, even while the calculations are being performed on a background thread.

However, my code doesn’t work and does not update the result in real-time. I would greatly appreciate your assistance in resolving these issues.

Thank you in advance for your help. Below is my code.

class DataModel: ObservableObject {
    @Published var input1: Double? = nil
    @Published var input2: Double? = nil
    
    @Published var multiplication: Double = 0
    @Published var input1by2: Double = 0
    @Published var input2by1: Double = 0
    
    func multiply() async {
        guard
            let input1 = input1,
            let input2 = input2 
        else { return }
        
        try? await Task.sleep(nanoseconds: 1000)
        let value = input1 * input2
        await MainActor.run {
            self.multiplication = value
        }
    }
    
    func division1() async {
        guard
            let input1 = input1,
            let input2 = input2
        else { return }
        
        try? await Task.sleep(nanoseconds: 1000)
        let value = input1 / input2
        await MainActor.run {
            self.input1by2 = value
        }
    }
    
    func division2() async {
        guard
            let input1 = input1,
            let input2 = input2
        else { return }
        
        try? await Task.sleep(nanoseconds: 1000)
        let value = input2 / input1
        await MainActor.run {
            self.input2by1 = value
        }
    }
}


struct ContentView: View {
    var body: some View {
        ZStack {
            VStack (spacing: 100) {
                ResultView()
                
                UserInput()
            }
        }
        .padding()
    }
}


struct ResultView: View {
    
    @EnvironmentObject var tap: DataModel
    
    var body: some View {
        VStack(alignment: .leading, spacing: 10) {
            HStack(spacing: 0) {
                Text("Multiplication: ")
                Text("(tap.multiplication, specifier: "%.2f")")
            }
            .task {
                await tap.multiply()
            }
            
            HStack(spacing: 0) {
                Text("Input1/Input2: ")
                Text("(tap.input1by2, specifier: "%.2f")")
            }
            .task {
                await tap.division1()
            }
            
            HStack(spacing: 0) {
                Text("Input2/Input1: ")
                Text("(tap.input2by1, specifier: "%.2f")")
            }
            .task {
                await tap.division2()
            }
        }
        .font(.title3)
        .foregroundStyle(Color.primary)
    }
}




struct UserInput: View {
    
    @EnvironmentObject var tap: DataModel
    
    var body: some View {
        VStack(spacing: 20) {
            HStack(spacing: 0) {
                Text("Input 1: ")
                    .padding(.horizontal, 6)
                
                TextField("123", value: $tap.input1, format: .number)
                    .foregroundStyle(Color.primary)
                    .keyboardType(.decimalPad)
            }
            .font(.headline)
            .frame(width: 200, height: 35)
            .background(
                RoundedRectangle(cornerRadius: 10)
                    .stroke(Color.blue.gradient, lineWidth: 2)
            
            )
            
            HStack(spacing: 0) {
                Text("Input 2: ")
                    .padding(.horizontal, 6)
                
                TextField("123", value: $tap.input2, format: .number)
                    .foregroundStyle(Color.primary)
                    .keyboardType(.decimalPad)
            }
            .font(.headline)
            .frame(width: 200, height: 35)
            .background(
                RoundedRectangle(cornerRadius: 10)
                    .stroke(Color.blue.gradient, lineWidth: 2)
            
            )
            
        }
    }
}