How to change the offset of an view using onTapGesture? - ios

Question

I am trying to move a view when it is being tapped. But unfortunately nothing happens. How do I toggle the position of it using the offset y axis?
struct Test: View {
#State var cards : [Card] = [Card(), Card(), Card(), Card(), Card(), Card()]
var body: some View {
VStack {
ZStack (alignment: .top){
ForEach (0..<cards.count) { i in
RoundedRectangle(cornerRadius: 10).frame(width: 250, height: 150)
.foregroundColor(Color.random).offset(y: self.cards[i].isFocus ? CGFloat(500) : CGFloat(i*50))
.zIndex(Double(i))
.onTapGesture {
self.cards[i].isFocus.toggle() // now the touched Card should move to an offset of y: 500, but nothing happens
}
}
}
Spacer()
}
}
}
struct Card :Identifiable{
#State var isFocus :Bool = false
var id = UUID()
}
struct Test_Previews: PreviewProvider {
static var previews: some View {
Test()
}
}
extension Color {
static var random: Color {
return Color(red: .random(in: 0...1),
green: .random(in: 0...1),
blue: .random(in: 0...1))
}
}

Answer 1

I see your code and I am sorry to say but its wrong in many aspects. I would recommend you to go through SwiftUI basics and understand how and when we use #State, #ObservedObject, #Binding etc. Also always try to break your Views into the smallest components.
Below is the code which I think fulfills your requirement.
struct Test: View {
var cards : [Card] = [Card(), Card(), Card(), Card(), Card(), Card()]
var body: some View {
VStack {
ZStack (alignment: .top){
ForEach (0..<cards.count) { i in
CardView(card: self.cards[i], i: i)
}
}
Spacer()
}
}
}
struct CardView: View {
#ObservedObject var card: Card
let i: Int
var body: some View {
RoundedRectangle(cornerRadius: 10).frame(width: 250, height: 150)
.foregroundColor(Color.random)
.offset(y: card.isFocus ? CGFloat(500) : CGFloat(i*10))
.zIndex(Double(i))
.onTapGesture {
withAnimation {
self.card.isFocus.toggle()
}
}
}
}
class Card: ObservableObject{
#Published var isFocus: Bool = false
var id = UUID()
}