Array of structs not updating in a view - swift

Question

I have an array of observed object, that contains an array of structs, that contain data. I would like to show it onscreen. This data is originally shown onscreen but the changes are not pushed whenever I make a change to an item in the array. I am even changing the property within the struct. I have tried it in my manager class aswell. I've done a bit of digging, changing my approach several times, but I can't get this working. I am very new to swiftui/swift as-well-as stack-overflow.
Full code:
struct GameView: View {
#State var value: CGFloat = 0
#ObservedObject var circles = GameCircles()
let timer = Timer.publish(every: 1, on: .main, in: .common).autoconnect()
var body: some View {
ZStack {
Color.primary
.frame(width: 450, height: 800)
self.circles.getViews()
.onReceive(timer) { _ in
self.circles.tick()
}
}
.edgesIgnoringSafeArea(.all)
.gesture(DragGesture(minimumDistance: 20)
.onChanged { gest in
self.value = gest.location.x
})
}
}
class GameCircles: ObservableObject {
#Published var circles: [GameCircle] = []
func getViews() -> some View {
ForEach(circles, id: \.id) { circle in
circle.makeView()
}
}
func tick() {
for circle in circles {
circle.tick()
print(circle.y)
}
circles.append(GameCircle(x: Int.random(in: -200...200), y: -200))
}
}
struct GameCircle: Identifiable {
#State var x: Int
#State var y: Int
let color = Color.random()
var id = UUID()
func tick() {
self.y += 1
}
func makeView() -> some View {
return ZStack {
Circle()
.frame(width: 40, height: 40)
.foregroundColor(color)
.animation(.default)
Text("\(Int(y))")
.foregroundColor(.black)
}
.offset(x: CGFloat(self.x), y: CGFloat(self.y))
}
}

Answer 1

I played with this code around, trying to solve your problem. And it was surprise for me, that state var in View didn't change in ForEach loop (you'll see it at the screenshot). Ok, I rewrite your code, now circles going down:
// MARK: models
class GameCircles: ObservableObject {
#Published var circles: [CircleModel] = []
func addNewCircle() {
circles.append(CircleModel(x: CGFloat.random(in: -200...200), y: -200))
}
}
struct CircleModel: Identifiable, Equatable {
let id = UUID()
var x: CGFloat
var y: CGFloat
mutating func pushDown() {
self.y += 5
}
}
// MARK: views
struct GameView: View {
#State var gameSeconds = 0
#ObservedObject var game = GameCircles()
let timer = Timer.publish(every: 1, on: .main, in: .common).autoconnect()
var body: some View {
ZStack {
Color.primary
.frame(width: 450, height: 800)
ForEach(self.game.circles) { circle in
CircleView(y: circle.y)
.offset(x: circle.x, y: circle.y)
.onReceive(self.timer) { _ in
let circleIndex = self.game.circles.firstIndex(of: circle)!
self.game.circles[circleIndex].pushDown()
}
}
.onReceive(self.timer) { _ in
self.game.addNewCircle()
}
}
.edgesIgnoringSafeArea(.all)
}
}
struct CircleView: View {
#State var y: CGFloat
var body: some View {
ZStack {
Circle()
.frame(width: 40, height: 40)
.foregroundColor(.red)
.animation(.default)
Text("\(Int(y))")
.foregroundColor(.black)
}
}
}
struct GameView_Previews: PreviewProvider {
static var previews: some View {
GameView()
}
}
as you can see #State var y doesn't change and I wonder why? Nevertheless, I hope it could help you.
P.S. I rewrote the code for a few times, so that is not the only solution and you may use tick() func as in the question and the code will be more clear
class GameCircles: ObservableObject {
#Published var circles: [CircleModel] = []
func tick() {
for index in circles.indices {
circles[index].pushDown()
}
circles.append(CircleModel(x: CGFloat.random(in: -200...200), y: -200))
}
}
struct GameView: View {
#State var gameSeconds = 0
#ObservedObject var game = GameCircles()
let timer = Timer.publish(every: 1, on: .main, in: .common).autoconnect()
var body: some View {
ZStack {
Color.primary
.frame(width: 450, height: 800)
ForEach(self.game.circles) { circle in
CircleView(y: circle.y)
.offset(x: circle.x, y: circle.y)
}
.onReceive(self.timer) { _ in
self.game.tick()
}
}
.edgesIgnoringSafeArea(.all)
}
}