Переходная анимация Swiftui не работает в первый раз ⇐ IOS

[Anonymous]

У меня есть небольшая проблема с переходной анимацией Swiftui. Учебное пособие создает приложение, похожее на Tinder, которое сжимает изображения слева и вправо. Если вы проведите, пройдите порог, то изображение удаляется из Hieraquie. Удаление изображения тригеров анимация перехода. Проблема в том, что когда я удаляю первую Imagem, анимация не происходит, но с второго изображения анимация работает очень хорошо. Я не знаю, что происходит. Я делаю то же самое со следующими Имимами, и анимация работает нормально:
< /p>
И здесь я замедлил анимацию на симуляторе. Вы можете видеть, что первая анимация работает нормально, когда анимация замедляется:
< /p>
Вот код, который я использую: < /p>
import SwiftUI

struct ContentView: View {

@GestureState private var dragState: DragState = .inactive
@State private var zIndexCounter: Double = 1_000_000_000.0
@State private var lastIndex: Int = 1
@State private var cardView: [CardView] = Array(trips[0.. self.dragThreshold {
self.removalTransition = .trailingBottom
}
}
.onEnded { value in
guard case .second(true, let drag?) = value,
drag.translation.width < -dragThreshold || drag.translation.width > dragThreshold
else {
return
}

moveCard()
}
)
}
}

Spacer(minLength: 20)

BottomBar { } likeAction: { } bookItNowAction: { }
.opacity(dragState.isDragging ? 0.0 : 1.0)
.animation(.default)
}
}

private func isTopCard(_ trip: CardView) -> Bool {
guard let index = cardView.firstIndex(where: { $0.id == trip.id }) else { return false }
return index == 0
}

private func zIndex(for trip: CardView) -> Double {
let idx = isTopCard(trip) ? zIndexCounter : zIndexCounter - 1
return idx
}

private func offset(for trip: CardView) -> CGSize {
return isTopCard(trip)
? CGSize(width: dragState.tranlation.width, height: dragState.tranlation.height)
: .zero
}

private func scaleEffect(for trip: CardView) -> CGFloat {
if isTopCard(trip) {
return dragState.isDragging ? 0.95 : 1.0
}

return 1.0
}

private func rotationEffect(for trip: CardView) -> Angle {
return isTopCard(trip) ? .degrees(Double(dragState.tranlation.width / 10)) : .zero
}

private func opacity(for trip: CardView, withXMark isXMark: Bool) -> Double {
if isTopCard(trip) {
if isXMark {
return dragState.tranlation.width < -dragThreshold ? 1.0 : 0
}
return dragState.tranlation.width > dragThreshold ? 1.0 : 0
}

return 0
}

private func moveCard() {
cardView.removeFirst()
lastIndex += 1
zIndexCounter -= 1
cardView.append(CardView(trip: trips[lastIndex % trips.count]))
}
}

struct ContentView_Previews: PreviewProvider {
static var previews: some View {
ContentView()
}
}

enum DragState: Equatable {
case inactive
case pressing
case dragging(translation: CGSize)

var tranlation: CGSize {
switch self {
case .inactive, .pressing:
return .zero
case let .dragging(translation):
return translation
}
}

var isDragging: Bool {
switch self {
case .dragging:
return true
case .pressing, .inactive:
return false
}
}

var isPressing: Bool {
switch self {
case .dragging, .pressing:
return true
case .inactive:
return false
}
}

static func == (lhs: Self, rhs: Self) -> Bool {
var result = false
switch (lhs, rhs) {
case (.inactive, .inactive), (.pressing, pressing):
result = true
case let (.dragging(translation1), .dragging(translation2)):
result = translation1 == translation2
default:
result = false
}
return result
}
}

extension AnyTransition {
static var trailingBottom: AnyTransition {
AnyTransition.asymmetric(
insertion: .identity,
removal: AnyTransition
.move(edge: .trailing)
.combined(with: .move(edge: .bottom))
)
}

static var leadingBottom: AnyTransition {
AnyTransition.asymmetric(
insertion: .identity,
removal: AnyTransition
.move(edge: .leading)
.combined(with: .move(edge: .bottom))
)
}
}

struct CardView: View, Identifiable {
let id = UUID()
let trip: Trip

var body: some View {
Image(trip.image)
.resizable()
.scaledToFill()
.frame(minWidth: 0, maxWidth: .infinity)
.cornerRadius(10)
.overlay(
Text(trip.destination)
.font(.system(.headline, design: .rounded))
.fontWeight(.bold)
.foregroundColor(.primary)
.padding(.vertical, 10)
.padding(.horizontal, 30)
.background(Color.white)
.cornerRadius(5)
.padding(.bottom),
alignment: .bottom)
}
}

struct Trip: Identifiable {
let id = UUID()
var destination: String
var image: String
}

var trips = [ Trip(destination: "Yosemite, USA", image: "yosemite-usa"),
Trip(destination: "Venice, Italy", image: "venice-italy"),
Trip(destination: "Hong Kong", image: "hong-kong"),
Trip(destination: "Barcelona, Spain", image: "barcelona-spain"),
Trip(destination: "Braies, Italy", image: "braies-italy"),
Trip(destination: "Kanangra, Australia", image: "kanangra-australia"),
Trip(destination: "Mount Currie, Canada", image: "mount-currie-canada"),
Trip(destination: "Ohrid, Macedonia", image: "ohrid-macedonia"),
Trip(destination: "Oia, Greece", image: "oia-greece"),
Trip(destination: "Palawan, Philippines", image: "palawan-philippines"),
Trip(destination: "Salerno, Italy", image: "salerno-italy"),
Trip(destination: "Tokyo, Japan", image: "tokyo-japan"),
Trip(destination: "West Vancouver, Canada", image: "west-vancouver-canada"),
Trip(destination: "Singapore", image: "garden-by-bay-singapore"),
Trip(destination: "Perhentian Islands, Malaysia", image: "perhentian-islands-malaysia")
]

struct BottomBar: View {
let discardAction: () -> Void
let likeAction: () -> Void
let bookItNowAction: () -> Void

var body: some View {
HStack {
Button(action: discardAction) {
Image(systemName: "xmark")
.font(.title)
}
Spacer()
Button(action: bookItNowAction) {
Text("BOOK IT NOW")
.font(.system(.subheadline, design: .rounded))
.fontWeight(.bold)
.padding(.horizontal, 35)
.padding(.vertical, 15)
.foregroundColor(.white)
.background(Color.primary)
.cornerRadius(10)
}
Spacer()
Button(action: likeAction) {
Image(systemName: "heart")
.font(.title)
}
}
.foregroundColor(.primary)
.padding()
}
}

struct TopBar: View {
let menuAction: () -> Void
let likeAction: () -> Void

var body: some View {
HStack {
Button(action: menuAction) {
Image(systemName: "line.horizontal.3")
.font(.title)
}
Spacer()
Image(systemName: "mappin.and.ellipse")
.font(.largeTitle)
Spacer()
Button(action: likeAction) {
Image(systemName: "heart.circle.fill")
.font(.title)
}
}
.padding()
.foregroundColor(.primary)
}
}
< /code>
Любое Sugestion?
Спасибо < /p>

Подробнее здесь: https://stackoverflow.com/questions/794 ... first-time