How to have ForEach in view updated when array values change with SwiftUI - swift

Question

I have this code here for updating an array and a dictionary based on a timer:
class applicationManager: ObservableObject {
static var shared = applicationManager()
#Published var applicationsDict: [NSRunningApplication : Int] = [:]
#Published var keysArray: [NSRunningApplication] = []
}
class TimeOpenManager {
var secondsElapsed = 0.0
var timer = Timer()
func start() {
timer = Timer.scheduledTimer(withTimeInterval: 1, repeats: true) { timer in
self.secondsElapsed += 1
let applicationName = ws.frontmostApplication?.localizedName!
let applicationTest = ws.frontmostApplication
let appMan = applicationManager()
if let appData = applicationManager.shared.applicationsDict[applicationTest!] {
applicationManager.shared.applicationsDict[applicationTest!] = appData + 1
} else {
applicationManager.shared.applicationsDict[applicationTest!] = 1
}
applicationManager.shared.keysArray = Array(applicationManager.shared.applicationsDict.keys)
}
}
}
It works fine like this and the keysArray is updated with the applicationsDict keys when the timer is running. But even though keysArray is updated, the HStack ForEach in WeekView does not change when values are added.
I also have this view where keysArray is being loaded:
struct WeekView: View {
static let shared = WeekView()
var body: some View {
VStack {
HStack(spacing: 20) {
ForEach(0..<8) { day in
if day == weekday {
Text("\(currentDay)")
.frame(width: 50, height: 50, alignment: .center)
.font(.system(size: 36))
.background(Color.red)
.onTapGesture {
print(applicationManager.shared.keysArray)
print(applicationManager.shared.applicationsDict)
}
} else {
Text("\(currentDay + day - weekday)")
.frame(width: 50, height: 50, alignment: .center)
.font(.system(size: 36))
}
}
}
HStack {
ForEach(applicationManager.shared.keysArray, id: \.self) {dictValue in
Image(nsImage: dictValue.icon!)
.resizable()
.frame(width: 64, height: 64, alignment: .center)
}
}
}
}
}

Answer 1

As mentioned in the comments, applicationManager should be an ObservableObject with #Published properties.
Then, you need to tell your view that it should look for updates from this object. You can do that with the #ObservedObject property wrapper:
struct WeekView: View {
#ObservedObject private var manager = applicationManager.shared
And later:
ForEach(manager.keysArray) {
Replace anywhere you had applicatoinManager.shared with manager within the WeekView
Additional reading: https://www.hackingwithswift.com/quick-start/swiftui/how-to-use-observedobject-to-manage-state-from-external-objects