Slider reading Dictionary Keys SwiftUI - dictionary

Question

How do I loop over my Dic keys on a slider? the slider behaivior is dividing the first key by the last key. what I want is only to loop throgh the keys value then somehow return the value's value...
struct ContentView: View {
#State private var currentValue = 0.0
#ObservedObject var scoreModel = ScoreModel()
var body: some View {
let endValue = Dictionary(uniqueKeysWithValues:
scoreModel.eventMDL.map { key, value in (key, value) })
return VStack {
Slider(value: $currentValue, in: endValue.keys.sorted()[1]...endValue.keys.sorted()[27])
.rotationEffect(Angle(degrees: -90))
Spacer()
Text("\(currentValue, specifier: "%.0f")")
}
.frame(height: 280)
}
}
The model:
#Published var eventMDL = [340.0: 100.0,
330.0: 97.0,
320.0: 94.0,
310.0: 92.0,
300.0: 90.0,
290.0: 88.0,
280.0: 86.0,
270.0: 84.0,
260.0: 82.0,
250.0: 80.0,
240.0: 78.0,
230.0: 76.0,
220.0: 74.0,
210.0: 72.0,
200.0: 70.0,
190.0: 68.0,
180.0: 65.0,
170.0: 64.0,
160.0: 63.0,
150.0: 62.0,
140.0: 60.0,
130.0: 50.0,
120.0: 40.0,
110.0: 30.0,
100.0: 20.0,
90.0: 10.0,
80.0: 0.0,
0.0 : 0.0]

Answer 1

First, I'd recommend creating an array with your keys and sort it. As you already use a #Published property I added updating this array in didSet:
class ScoreModel: ObservableObject {
#Published var eventMDL = [
340.0: 100.0,
...
0.0: 0.0,
] {
didSet {
eventMDLKeysSorted = eventMDL.keys.reversed().sorted()
}
}
lazy var eventMDLKeysSorted: [Double] = eventMDL.keys.reversed().sorted()
}
However, if the eventMDL dictionary is assigned only once, there's no need for it to be #Published:
class ScoreModel: ObservableObject {
let eventMDL = [
340.0: 100.0,
...
0.0: 0.0,
]
lazy var eventMDLKeysSorted: [Double] = eventMDL.keys.reversed().sorted()
}
Then keep track of current key instead of value:
#State private var currentKey = 0.0
Then create a range:
var firstKey: Double {
scoreModel.eventMDLKeysSorted[1]
}
var lastKey: Double {
scoreModel.eventMDLKeysSorted[scoreModel.eventMDLKeysSorted.count - 1]
}
and set it for the Slider adding a step of 10 (the difference between the subsequent keys):
Slider(value: $currentKey, in: firstKey...lastKey, step: 10)
Then we access the current value:
var currentValue: Double {
scoreModel.eventMDL[currentKey]!
// or provide a default value
// or make currentValue optional
}
Summing up this is how your ContentView might look like:
struct ContentView: View {
#ObservedObject var scoreModel = ScoreModel()
#State private var currentKey = 0.0
var firstKey: Double {
scoreModel.eventMDLKeysSorted[1]
}
var lastKey: Double {
scoreModel.eventMDLKeysSorted[scoreModel.eventMDLKeysSorted.count - 1]
}
var currentValue: Double {
return scoreModel.eventMDL[currentKey]!
}
var body: some View {
VStack {
Slider(value: $currentKey, in: firstKey...lastKey, step: 10)
.rotationEffect(Angle(degrees: -90))
Spacer()
Text("\(currentValue, specifier: "%.0f")")
}
.frame(height: 280)
}
}
Also you may want to set the Slider's start position:
init() {
_currentKey = .init(initialValue: scoreModel.eventMDLKeysSorted[1])
}