Animation conflict issue with another animation - ios

I have this LoaderView which grow with given value, I want add some highlight effect to it as well, So basically there is 2 deferent and separate animation happening, one for activeValue and one for the highlight. i did not combine them together because they are 2 deferent things, but my output of codes combine these 2 values together and destroys highlight effect. I am looking a solid answer for my issue to having this 2 animation works side by side.
The issue happens when i add value.
I want this view be usable in macOS as well, so there is a possibility user changes the Window size, then my view would be changed as well.
struct ContentView: View {
#State private var value: CGFloat = 50
var body: some View {
LoaderView(activeValue: value, totalValue: 100)
.padding()
Button("add") { value += 10 }
.padding()
}
}
struct LoaderView: View {
let activeValue: CGFloat
let totalValue: CGFloat
let activeColor: Color
let totalColor: Color
init(activeValue: CGFloat, totalValue: CGFloat, activeColor: Color = Color.green, totalColor: Color = Color.secondary) {
if activeValue >= totalValue { self.activeValue = totalValue }
else if activeValue < 0 { self.activeValue = 0 }
else { self.activeValue = activeValue }
self.totalValue = totalValue
self.activeColor = activeColor
self.totalColor = totalColor
}
#State private var startAnimation: Bool = .init()
private let heightOfCapsule: CGFloat = 5.0
var body: some View {
let linearGradient = LinearGradient(colors: [Color.yellow.opacity(0.1), Color.yellow], startPoint: .leading, endPoint: .trailing)
return GeometryReader { proxy in
totalColor
.overlay(
Capsule()
.fill(activeColor)
.frame(width: (activeValue / totalValue) * proxy.size.width)
.overlay(
Capsule()
.fill(linearGradient)
.frame(width: 100)
.offset(x: startAnimation ? 100 : -100),
alignment: startAnimation ? Alignment.trailing : Alignment.leading)
.clipShape(Capsule()),
alignment: Alignment.leading)
.clipShape(Capsule())
}
.frame(height: heightOfCapsule)
.onAppear(perform: { startAnimation.toggle() })
.animation(Animation.default, value: activeValue)
.animation(Animation.linear(duration: 3.0).repeatForever(autoreverses: false), value: startAnimation)
}
}

The issue isn't the .animations it is that .onAppear is only called once, so your animation never restarts. startAnimation needs to be toggled when activeValue changes. The way your animation works, toggling startAnimation reverses the animation direction. Therefore, I set autoreverses: true. It is a compromise either way.
struct LoaderView: View {
//Nothing changed in this portion
.onAppear{
DispatchQueue.main.asyncAfter(deadline: .now() + 0.5) {
startAnimation.toggle()
}
}
// The issue is that .onAppear() is only called once.
.onChange(of: activeValue, perform: { _ in
startAnimation.toggle()
})
.animation(Animation.default, value: activeValue)
// As a side effect, changing startAnimation to opposite values reverses the animation
// you have made, so setting autoreverses: true hides this.
.animation(Animation.linear(duration: 3.0).repeatForever(autoreverses: true), value: startAnimation)
}
}
Edit:
I apologize for not getting back to this sooner. The issue with the rubber band animation is because of the transition when the app firsts launches. To prevent this, you need to wrap your variable change in .onAppear() in a DispatchQueue.main.asyncAfter(deadline:) with enough time for the view to load. Then when you start the animation, it works correctly.

Related

Scaled view unexpectedly moving up and down when pushed from navigation view

I have a view that should scale in and out, starting immediately when the view is shown and repeating forever. However, I find that it's actually animating up and down as well as scaling much like in this post when it's pushed from a navigation view:
struct PlaceholderView: View {
#State private var isAnimating = false
var body: some View {
Circle()
.frame(width: 30, height: 30)
.scaleEffect(self.isAnimating ? 0.8 : 1)
.animation(Animation.easeInOut(duration: 1).repeatForever())
.onAppear {
self.isAnimating = true
}
.frame(width: 50, height: 50)
.contentShape(
Rectangle()
)
}
}
struct SettingsView: View {
#State private var showPlaceholder = false
var body: some View {
NavigationView {
ZStack {
Button(
action: {
showPlaceholder = true
}, label: {
Text("Go to placeholder")
}
)
NavigationLink(
destination: PlaceholderView(),
isActive: $showPlaceholder
) {
EmptyView()
}
.hidden()
}
}
.navigationViewStyle(.stack)
}
}
Why is this and how can I stop this from happening?
UPDATE:
Wrapping self.isAnimating = true in DispatchQueue.main.async {} fixes the issue, but I don't understand why...
I can reproduce the problem, but I wasn't able to reproduce your DispatchQueue.main.async {} fix.
Here is how I fixed it:
Animation is made by comparing a before state and and after state and animating between them. With an implicit animation, the before state is the position of the circle before it is added to the navigation view. By switching to an explicit animation and setting your before state after the view appears, the move animation is avoided and you only get the scaling:
Replace isAnimating with scale. In onAppear {}, first establish the before scale of 0.8, then animate the change to scale 1:
struct PlaceholderView: View {
// To work correctly, this initial value should be different
// than the before value set in .onAppear {}.
#State private var scale = 1.0
var body: some View {
Circle()
.frame(width: 30, height: 30)
.scaleEffect(self.scale)
.onAppear {
self.scale = 0.8 // before
withAnimation(.easeInOut(duration: 1).repeatForever()) {
self.scale = 1 // after
}
}
.frame(width: 50, height: 50)
.contentShape(
Rectangle()
)
}
}

SwiftUI - Rendering anomaly with repeatForever animation placed in a NavigationView [duplicate]

When I put an explicit animation inside a NavigationView, as an undesirable side effect, it animates the initial layout of the NavigationView content. It gets especially bad with infinite animations. Is there a way to disable this side effect?
Example: the image below is supposed to be an animated red loader on a full screen blue background. Instead I get this infinite loop of a scaling blue background:
import SwiftUI
struct EscapingAnimationTest: View {
var body: some View {
NavigationView {
VStack {
Spacer()
EscapingAnimationTest_Inner()
Spacer()
}
.backgroundFill(Color.blue)
}
}
}
struct EscapingAnimationTest_Inner: View {
#State var degrees: CGFloat = 0
var body: some View {
Circle()
.trim(from: 0.0, to: 0.3)
.stroke(Color.red, lineWidth: 5)
.rotationEffect(Angle(degrees: degrees))
.onAppear() {
withAnimation(Animation.linear(duration: 1).repeatForever(autoreverses: false)) {
degrees = 360
}
}
}
}
struct EscapingAnimationTest_Previews: PreviewProvider {
static var previews: some View {
EscapingAnimationTest()
}
}
Here is fixed part (another my answer with explanations is here).
Tested with Xcode 12 / iOS 14.
struct EscapingAnimationTest_Inner: View {
#State var degrees: CGFloat = 0
var body: some View {
Circle()
.trim(from: 0.0, to: 0.3)
.stroke(Color.red, lineWidth: 5)
.rotationEffect(Angle(degrees: Double(degrees)))
.animation(Animation.linear(duration: 1).repeatForever(autoreverses: false), value: degrees)
.onAppear() {
DispatchQueue.main.async { // << here !!
degrees = 360
}
}
}
}
Update: the same will be using withAnimation
.onAppear() {
DispatchQueue.main.async {
withAnimation(Animation.linear(duration: 1).repeatForever(autoreverses: false)) {
degrees = 360
}
}
}
Using DispatchQueue.main.async before outside of the withAnimation blocks worked for me but this code didn't look very clean.
I found another (and in my opinion cleaner) solution which is this:
Create a isAnimating variable outside of the body
#State var isAnimating = false
Then at the end of your outer VStack, set this variable to true inside onAppear. Then call rotationEffect with isAnimating ternary operator and then clal .animation() after. Here is the full code:
var body: some View {
VStack {
// the trick is to use .animation and some helper variables
Circle()
.trim(from: 0.0, to: 0.3)
.stroke(Color.red, lineWidth: 5)
.rotationEffect(Angle(degrees: isAnimating ? 360 : 0))
.animation(Animation.linear(duration:1).repeatForever(autoreverses: false), value: isAnimating)
} //: VStack
.onAppear {
isAnimating = true
}
}
This way you don't need to use DispatchQueue.main.async.

SwiftUI handling button/view with onTapGesture and onLongPressGesture with a release action

I have a view that has both onTapGesture and onLongPressGesture simultaneously. The issue is that the implementation of my onLongPressGesture prevents onTapGesture from ever being called.
Here is some code
View()
.onTapGesture {
action_1
}
.onLongPressGesture(minimumDuration: 0.5, maximumDistance: 10, pressing: {
pressing in
self.isPressing = pressing
if (pressing) {action_2}
if !pressing {action_3}
}, perform: {})
The pressing argument in .onLongPressGesture detects if a user is pressing the view/button, and will always perform the .onLongPressGesture, regardless of what the minimumDuration is.
Edit
Snapchat shutter where you can tap to take a picture, hold the button to start recording a video, then release the button to stop recording the video. That is why there are three actions that need to be performed.
This is tricky. Here's what I did:
onTapGesture, for the tap gesture
LongPressGesture, for a 0.5 second delay. Once the 0.5 seconds is over (.onEnded), start the recording.
DragGesture, for observing when the finger lift off the screen. When this happens, stop the recording.
struct ContentView: View {
/// for visual indicators
#State var recording = false
#State var tapped = false
var body: some View {
let longPressDrag = LongPressGesture(minimumDuration: 0.5) /// 2.
.onEnded { _ in /// 0.5 seconds is over, start recording
print("Long press start")
recording = true
}
.sequenced(before: DragGesture(minimumDistance: 0)) /// 3.
.onEnded { _ in /// finger lifted, stop recording
print("Long press release")
recording = false
}
Circle()
.fill(recording ? Color.red : Color.blue)
.opacity(tapped ? 0.5 : 1)
.frame(width: 100, height: 100)
.onTapGesture { /// 1.
print("Tapped")
tapped = true
DispatchQueue.main.asyncAfter(deadline: .now() + 0.3) { tapped = false }
}
.gesture(longPressDrag)
}
}
Result:
Old answer: The pressing parameter isn't for performing actions like action_2. You can, but it's more commonly used for changing #State, so for example highlighting the view in green when it's pressed. You can find more information in the community documentation.
Instead, what you probably want is to call your action (action_2/print("long")) in the perform closure.
struct ContentView: View {
var body: some View {
Text("Hi")
.font(.title)
.onTapGesture {
print("tap")
}
.onLongPressGesture(minimumDuration: 0.5, maximumDistance: 10) {
print("long")
}
}
}
Result:
XCode 14. Swift 5 I have added both gesture to Image View. On tap gesture image will be scale and unscale. On LongPressGesture image bg color will change. Provide count: 2 to make it doubleTapGesture.
struct ContentView: View {
// MARK: - Property
#State private var isAnimating: Bool = false
#State private var imageScale: CGFloat = 1
#State private var shadowColor: Color = .black
// MARK: - Content
var body: some View {
NavigationView {
ZStack {
Image("magazine-front-cover")
.resizable()
.aspectRatio(contentMode: .fit)
.cornerRadius(8)
.padding()
.shadow(color: shadowColor, radius: 22, x: 2, y: 2)
.opacity(isAnimating ? 1 : 0)
.animation(.linear(duration: 1), value: isAnimating)
.scaleEffect(imageScale)
// MARK: - 1. Tap Gesture
.onTapGesture(count: 1, perform: {
if imageScale == 1 {
withAnimation(.spring()) {
imageScale = 5
}
} else {
withAnimation(.spring()) {
imageScale = 1
}
}
})
// MARK: - 2. LongPress Gesture
.onLongPressGesture(perform: {
if shadowColor == .black {
shadowColor = .green
} else {
shadowColor = .black
}
})
}
.ignoresSafeArea(edges: .all)
.navigationTitle("Pinch & Zoom")
.navigationBarTitleDisplayMode(.inline)
.onAppear {
isAnimating = true
}
} // END of Navigation View
}
}

Multiple animations do not work as expected in SwiftUI

I want to create a pulsing circle with forever repeating animation. It should have a gradual change of size and a momentary change of color when animation direction changes.
I have two different animations for that, but only the last one having an effect on both (size and color change).
struct SwiftUIView: View {
#State private var animationStarted = false
let side = UIScreen.main.bounds.size.width
let animation1 = Animation.easeInOut(duration: 0.3).delay(5.7)
.repeatForever(autoreverses: true)
let animation2 = Animation.easeInOut(duration: 6)
.repeatForever(autoreverses: true)
var body: some View {
HStack {
VStack {
HStack {
Circle()
.foregroundColor(self.animationStarted ? Color.pink : Color.blue)
.animation(animation1)
.frame(width: self.animationStarted ? 10 : side, height: self.animationStarted ? 10 : side)
.animation(animation2)
.onAppear {
self.animationStarted.toggle()
}
}
}.frame(height: side)
}.frame(width: side)
}
}

SwiftUI: Text issue during animations

I have a problem with an animation that involves a Text. Basically I need to change the text and animate its position. Take a look at this simple example here below:
import SwiftUI
struct ContentView: View {
#State private var isOn = false
#State private var percentage = 100
var body: some View {
ZStack {
Text("\(percentage)")
.font(.title)
.background(Color.red)
.position(isOn ? .init(x: 150, y: 300) : .init(x: 150, y: 100))
.animation(.easeOut(duration: 1), value: isOn)
VStack {
Spacer()
Button(action: {
self.isOn.toggle()
//just to make the issue happen
if self.percentage == 100 {
self.percentage = 0
} else {
self.percentage = 100
}
}, label: {
Text("SWITCH")
})
}
}
}
}
struct ContentView_Previews: PreviewProvider {
static var previews: some View {
ContentView()
}
}
The result is:
There are some issues here. Probably the most annoying is the glitch with the ... I just want to animate the position of the Text, I don't want to animate the text itself and I don't want to animate the width of the text. Any ideas? Thank you.
The possible alternate is to add scaling factor, it supersedes truncation mode and gives different effect, which under some circumstances might be preferable.
The only needed changes is as below (factor modifiable of course)
Text("\(percentage)")
.minimumScaleFactor(0.5)
Try this action on the button:
Button(action:
{
//just to make the issue happen
if self.percentage == 100
{
self.percentage = 0
}
else
{
self.percentage = 100
}
withAnimation(.easeInOut(duration: 1.0)) {
self.isOn.toggle()
}
}, label: {
Text("SWITCH")
})
And remove that line from your Label
.animation(.easeOut(duration: 1), value: isOn)
I didn't test it yet.

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