Created
May 23, 2020 09:34
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Weird behavior when using transition with views that have animations.
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// | |
// LoadingIndicator.swift | |
// AnimationTransitionDemo | |
// | |
// Created by Vijaya Prakash Kandel on 5/23/20. | |
// Copyright © 2020 Vijaya Prakash Kandel. All rights reserved. | |
// | |
import SwiftUI | |
struct LoadingIndicator: View { | |
@State private var isRotating: Bool = false | |
private let animation = Animation.linear(duration: 2.0).repeatForever(autoreverses: false) | |
var body: some View { | |
VStack { | |
Image(systemName: "rays") | |
.rotationEffect(isRotating ? .init(degrees: 360) : .init(degrees: 0)) | |
// Implict animation. SwiftUI will animate the transition/ change on this using the same auto repeat. Therefore sliding out never actually slides out this view. | |
// .animation(animation) | |
.onAppear { | |
// Explicit Animation. We tell SwiftUI which state change we are interested to change exclusively | |
withAnimation(self.animation) { | |
self.isRotating = true | |
} | |
} | |
} | |
} | |
} | |
struct SettingsView: View { | |
var body: some View { | |
Image(systemName: "gear") | |
} | |
} | |
struct SettingsMorphedLoadingView: View { | |
@State private var isLoading: Bool = true | |
var body: some View { | |
HStack { | |
if isLoading { | |
LoadingIndicator() | |
.onTapGesture { | |
withAnimation(.default) { | |
self.isLoading.toggle() | |
} | |
} | |
.transition(AnyTransition.scale.combined(with: .opacity)) | |
} else { | |
SettingsView() | |
.transition(AnyTransition.scale.combined(with: .opacity)) | |
.onTapGesture { | |
// using explicit animation both `loadingIndicator` | |
// and `transition` works but can't reason why? | |
withAnimation(.default) { | |
self.isLoading.toggle() | |
} | |
} | |
} | |
} | |
// using implicit animation `transition` works | |
// but the `loadingIndicator` wont spin after transitioning | |
// inFact `loadingIndicator` spins during the transition period and stops. | |
.animation(.default) | |
} | |
} | |
struct LoadingIndicator_Previews: PreviewProvider { | |
static var previews: some View { | |
VStack { | |
LoadingIndicator() | |
SettingsMorphedLoadingView() | |
} | |
} | |
} | |
Author
kandelvijaya
commented
May 23, 2020
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