Is there an opposite to .onAppear modifier in SwfitUI? - swiftui

Question

I created a custom horizontal scroll, which uses animation to scroll.
When the view is presented, it uses animation to present the views.
So when I invoke the view and the onAppear is initiated, it changes the offset with animation, But this behavior is unwanted. I don't want to animate my view when they are created.
I tried to create #State variable
#State private var myBool = false
and create a condition:
.animation(self.myBool ? Animation.spring : .none)
and then inside .onAppear
.onAppear(
...
some code that changing state variables
...
self.myBool = true
)
but it didn't work, it still uses the animation even when myBool is false
How can I allow animation only AFTER the body is created?
I mean, is there a modifier .onFinish?
This is an example of the code:
struct scroll: View {
#State var offset: 0
var body: some View {
GeometryReader { geo in
HStack {
ForEach(0..<5) { i in
Rectangle()
}
}
.gesture(DragGesture()
.onChange ({ (value) in
self.offset = value.translation.width
}
.onEnded ({ _ in
self.offset = 50
}
)
.offset(x: self.offset)
.animation(.spring)
.onAppear (
self.offset = geo.size.width
)
}
}
}

Answer 1

As I see now you just need to set initial value directly
struct scroll: View {
var body: some View {
GeometryReader { geo in
innerScroll(offset: geo.size.width) // << here !!
}
}
struct innerScroll: View { // inner subview
#State var offset: CGFloat
var body: some View {
HStack {
ForEach(0..<5) { i in
Rectangle()
}
}
.gesture(DragGesture()
.onChanged { (value) in
self.offset = value.translation.width
}
.onEnded { _ in
self.offset = 50
}
)
.offset(x: self.offset)
.animation(.spring())
}
}
}

Answer 2

Maybe I am misunderstanding your question, but if you don't want any animation onAppear, why don't you initialize your offset with 150?
Instead you start with 0 and set it to 150 onAppear which seems to be the reason for the animation because the variable changes onAppear.