#State var not changing - SwiftUI picker - swiftui

Question

I am a real newbie in swift, but I am stuck at this problem...
I am building a picker to change an optical prescription, but I am not able to change SPH and CYL values (doubles), while AX works good. Any help?
Also the way that text comes out, I tried to add .format modifier just to show 2 decimals, but still no luck.
Thanks!
import SwiftUI
struct ContentView: View {
#State var selectedsph = 0.0
#State var selectedcyl = 0.0
#State var selectedax = 0
var sph : [Double] = Array(stride(from: -20.00, through: 20.00, by: 0.25))
var cyl : [Double] = Array(stride(from: -10.00, through: 10.00, by: 0.25))
var ax = [Int](0...180)
var body: some View {
GeometryReader { geometry in
VStack {
Spacer()
HStack(spacing:0) {
Picker(selection: self.$selectedsph, label: Text("")) {
ForEach(0 ..< self.sph.count) { index in
Text("Sph " + "\(self.sph[index])").tag(index)
}
}
.pickerStyle(.wheel)
.frame(width: geometry.size.width/3, height: 150)
.compositingGroup()
.clipped()
Picker(selection: self.$selectedcyl, label: Text("Picker")) {
ForEach(0 ..< self.cyl.count) { index in
Text("Cyl " + "\(self.cyl[index])").tag(index)
}
}
.pickerStyle(.wheel)
.frame(width: geometry.size.width/3.5, height: 150)
.compositingGroup()
.clipped()
Picker(selection: self.$selectedax, label: Text("Picker")) {
ForEach(0 ..< self.ax.count) { index in
Text("AX " + "\(self.ax[index])").tag(index)
}
}
.pickerStyle(.wheel)
.frame(width: geometry.size.width/3, height: 150)
.compositingGroup()
.clipped()
}.padding()
}
HStack(alignment: .center) {
Text("Occhio Destro: SF: \(selectedsph) Cyl: \(selectedcyl) Ax: \(selectedax)")
.fontWeight(.medium).multilineTextAlignment(.center).padding(.all)
}
Spacer()
}
}
}

Answer 1

The picker values are the indices of the selected values. Change your #State vars to hold Int:
#State var selectedsph = 0
#State var selectedcyl = 0
#State var selectedax = 0
And change your Text to use the indices to look up the values. Add specifier: "%.2f" to show just 2 decimal places:
Text("Occhio Destro: SF: \(sph[selectedsph], specifier: "%.2f") Cyl: \(cyl[selectedcyl], specifier: "%.2f") Ax: \(ax[selectedax])")
.fontWeight(.medium).multilineTextAlignment(.center).padding(.all)