SwiftUI @State Variables

Question

*I have these three @State variables:

@State var mhzValue : Float = 0 
@State var mhzValueStep : Float = 0 
@State var TotalFrequency : Float = 0

And although they mhzValue & mhzValueStep display on in my app..

I wish to add them together..

Example: var TotalFrequency = mhzValue + mhzValueStep

But I just cannot get it to work..

Any suggestions please.. I am a very new to this... Thanks !*

import SwiftUI
struct DipoleView : View {

    @State var mhzValue : Float = 0
    @State var mhzValueStep : Float = 0
    @State var TotalFrequency : Float = 0

    var body: some View {
        VStack {
            //Slider one
            Text("Slide to select Frequency")
                .font(.headline)
                .color(.blue)
                .padding(.leading, -130.0)
            Slider(value: $mhzValue, from: 1, through: 55, by: 1)
                .padding(.horizontal)

            Text("\(Int(mhzValue)) in Mhz")
                .font(.title)
                .fontWeight(.semibold)
                .color(.blue)
            // Slider Two
            Text("Slide to select Decimal Point")
                .font(.headline)
                .color(.orange)
                .padding(.leading, -130.0)

            Slider(value: $mhzValueStep, from: 1, through: 999, by: 0.1)
                .padding(.horizontal)
            Text(".\(Int(mhzValueStep)) in Mhz")
                .font(.title)
                .fontWeight(.semibold)
                .color(.orange)
            Text(" Frequency:  \(Int(mhzValue)).\(Int(mhzValueStep)) Mhz")
                .font(.largeTitle)
                .fontWeight(.medium)
                .color(.white)
                .padding(10)
                .background(/*@START_MENU_TOKEN@*/Color.blue/*@END_MENU_TOKEN@*/)
                .cornerRadius(10.0)
                .shadow(radius: /*@START_MENU_TOKEN@*/10/*@END_MENU_TOKEN@*/)

            // Load Image View
            Spacer()
            ImageView()
                .padding(.bottom, 40)

        }
    }
}

#if DEBUG
struct DipoleView_Previews : PreviewProvider {
    static var previews: some View {
        DipoleView()
    }
}
#endif

Sorry about the very bad formatting of the text.

Craig Shine
– Craig Shine

2019-06-28 02:51:30 +00:00
Commented Jun 28, 2019 at 2:51 — Craig Shine
– Craig Shine, Commented Jun 28, 2019 at 2:51
Nothing to worry about, formatting looks fine!

Hoppeduppeanut
– Hoppeduppeanut

2019-06-28 04:08:31 +00:00
Commented Jun 28, 2019 at 4:08 — Hoppeduppeanut
– Hoppeduppeanut, Commented Jun 28, 2019 at 4:08

Md Shafiul Islam · Accepted Answer · 2019-06-28 04:18:08Z

You don't need to declare TotalFrequency as a State variable cause both the mhzValue and mhzValueStep are declared as State var and you just need the sum of this two. Rather you can declare TotalFrequency as a computed var. Here is a working version of the code.

import SwiftUI
struct ContentView : View {

    @State var mhzValue : Float = 0
    @State var mhzValueStep : Float = 0
    private var TotalFrequency : Float {
        return mhzValue + mhzValueStep
    }

    var body: some View {
        VStack {
            //Slider one
            Text("Slide to select Frequency")
                .font(.headline)
                .color(.blue)
                .padding(.leading, -130.0)
            Slider(value: $mhzValue, from: 1, through: 55, by: 1)
                .padding(.horizontal)

            Text("\(Int(mhzValue)) in Mhz")
                .font(.title)
                .fontWeight(.semibold)
                .color(.blue)
            // Slider Two
            Text("Slide to select Decimal Point")
                .font(.headline)
                .color(.orange)
                .padding(.leading, -130.0)

            Slider(value: $mhzValueStep, from: 0, through: 1, by: 0.1)
                .padding(.horizontal)
            Text("\(mhzValueStep) in Mhz")
                .font(.title)
                .fontWeight(.semibold)
                .color(.orange)

            Text(" Frequency:  \(TotalFrequency) Mhz")
                .font(.largeTitle)
                .fontWeight(.medium)
                .color(.white)
                .padding(10)
                .background(/*@START_MENU_TOKEN@*/Color.blue/*@END_MENU_TOKEN@*/)
                .cornerRadius(10.0)
                .shadow(radius: /*@START_MENU_TOKEN@*/10/*@END_MENU_TOKEN@*/)

            // Load Image View
            Spacer()
        //    Image()
       //         .padding(.bottom, 40)

        }
    }
}

Thank you so much... that works... Now I can move forward on this.... I have been playing around with Xcode and Swift for a couple of years and continue to hit brick walls.. People like you are so helpful and I really appreciate it.. I'm in my 60's and find it hard now to remember... Thank you again !!

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