this simple code of x offset animation causes a text to move also on y axis when the text is part of a button (on tvOS 14.7)
struct Animate: View
{
#State var scrollText: Bool = false
var body: some View {
Button(action: {}, label: {
Text("This is My Text !")
.offset(x: scrollText ? 0 : 200, y: 0)
.animation(Animation.linear(duration: 1).repeatForever(autoreverses: true))
.onAppear {
self.scrollText.toggle()
}
})
}
}
see the animation behavior here:
marquee gone wrong
How can i stop the y axis movement ?
You always need to set a value for your animations. Otherwise, SwiftUI will animate all changes, include unwanted positioning.
struct Animate: View {
#State var scrollText: Bool = false
var body: some View {
Button(action: {}) {
Text("This is My Text !")
.offset(x: scrollText ? 0 : 200, y: 0)
.animation(Animation.linear(duration: 1).repeatForever(autoreverses: true), value: scrollText) /// only update animation when `scrollText` changes
.onAppear {
// DispatchQueue.main.async { /// you might also need this
self.scrollText.toggle()
// }
}
}
}
}
Result:
This video might also be helpful
Related
I have been using the following UIView extension for quite a while to fade text in and out. I have been trying to figure out how to implement this with SwiftUI but so far haven't found anything that exactly addresses this for me. Any help would be greatly appreciated.
extension UIView {
func fadeKey() {
// Move our fade out code from earlier
UIView.animate(withDuration: 3.0, delay: 2.0, options: UIView.AnimationOptions.curveEaseIn, animations: {
self.alpha = 1.0 // Instead of a specific instance of, say, birdTypeLabel, we simply set [thisInstance] (ie, self)'s alpha
}, completion: nil)
}
func fadeIn1() {
// Move our fade out code from earlier
UIView.animate(withDuration: 1.5, delay: 0.5, options: UIView.AnimationOptions.curveEaseIn, animations: {
self.alpha = 1.0 // Instead of a specific instance of, say, birdTypeLabel, we simply set [thisInstance] (ie, self)'s alpha
}, completion: nil)
}
I assume this is what you wanted. Try this below code:
struct FadeView: View {
#State var isClicked = false
#State var text = "Faded Text"
var body: some View {
VStack {
Text(text) //fade in and fade out
.opacity(isClicked ? 0 : 1)
Button("Click to animate") {
withAnimation {
isClicked.toggle()
}
}
}
}
}
You could use withAnimation function and manipulate the duration, options and delay
struct ContentView: View {
#State var isActive = false
var body: some View {
VStack {
Button("Fade") {
withAnimation(.easeIn(duration: 3.0).delay(2)){
isActive.toggle()
}
}
Rectangle()
.frame(width: 222.0, height: 222.0)
.opacity(isActive ? 0 : 1)
}
}
}
I'm still new to SwiftUI. I'm trying to get each change of an image to start out at opacity 0.0 (fully transparent), then increase to opacity 1.0 (fully opaque)
I expected I could achieve this using the .opacity transition. .opacity is described as a "transition from transparent to opaque on insertion", so my assumption is that by stating "withAnimation" in my Button action, I'd trigger the Image to be re-rendered, and the transition would occur beginning from faded to transparent. Instead I see the same instant appear of the new shape & slow morphing to a new size, no apparent change in .opacity. Code and .gif showing current result, below. I've used UIKit & know I'd set alpha to zero, then UIView.animate to alpha 1.0 over a duration of 1.0, but am unsure how to get the same effect in SwiftUI. Thanks!
struct ContentView: View {
#State var imageName = ""
var imageNames = ["applelogo", "peacesign", "heart", "lightbulb"]
#State var currentImage = -1
var body: some View {
VStack {
Spacer()
Image(systemName: imageName)
.resizable()
.scaledToFit()
.padding()
.transition(.opacity)
Spacer()
Button("Press Me") {
currentImage = (currentImage == imageNames.count - 1 ? 0 : currentImage + 1)
withAnimation(.linear(duration: 1.0)) {
imageName = imageNames[currentImage]
}
}
}
}
}
The reason you are not getting the opacity transition is that you are keeping the same view. Even though it is drawing a different image each time, SwiftUI sees Image as the same. the fix is simple: add .id(). For example:
Image(systemName: imageName)
.resizable()
.scaledToFit()
.padding()
.transition(.opacity)
// Add the id here
.id(imageName)
Here is the correct approach for this kind of issue:
We should not forgot how transition works!!! Transition modifier simply transmit a view to nothing or nothing to a view (This should be written with golden ink)! in your code there is no transition happening instead update happing.
struct ContentView: View {
#State var imageName1: String? = nil
#State var imageName2: String? = nil
var imageNames: [String] = ["applelogo", "peacesign", "heart", "lightbulb"]
#State var currentImage = -1
var body: some View {
VStack {
Spacer()
ZStack {
if let unwrappedImageName: String = imageName1 {
Image(systemName: unwrappedImageName)
.resizable()
.transition(AnyTransition.opacity)
.animation(nil, value: unwrappedImageName)
.scaledToFit()
}
if let unwrappedImageName: String = imageName2 {
Image(systemName: unwrappedImageName)
.resizable()
.transition(AnyTransition.opacity)
.animation(nil, value: unwrappedImageName)
.scaledToFit()
}
}
.padding()
.animation(.linear, value: [imageName1, imageName2])
Spacer()
Button("Press Me") {
currentImage = (currentImage == imageNames.count - 1 ? 0 : currentImage + 1)
if imageName1 == nil {
imageName2 = nil; imageName1 = imageNames[currentImage]
}
else {
imageName1 = nil; imageName2 = imageNames[currentImage]
}
}
}
}
}
It's easy to have an animation begin when a view appears, by using .onAppear(). But I'd like to perform a repeating animation whenever one of the view's non-State variables changes. An example:
Here is a view that I would like to "throb" whenever its throbbing parameter, set externally, is true:
struct MyCircle: View {
var throbbing: Bool
#State var scale = 1.0
var body: some View {
Circle()
.frame(width: 100 * scale, height: 100 * scale)
.foregroundColor(.blue)
.animation(.easeInOut.repeatForever(), value: scale)
.onAppear { scale = 1.2 }
}
}
Currently the code begins throbbing immediately, regardless of the throbbing variable.
But imagine this scenario:
struct ContentView: View {
#State var throb: Bool = false
var body: some View {
VStack {
Button("Throb: \(throb ? "ON" : "OFF")") { throb.toggle() }
MyCircle(throbbing: throb)
}
}
}
It looks like this:
Any ideas how I can modify MyCircle so that the throbbing starts when the button is tapped and ends when it is tapped again?
You can use onChange to watch throbbing and then assign an animation. If true, add a repeating animation, and if false, just animate back to the original scale size:
struct MyCircle: View {
var throbbing: Bool
#State private var scale : CGFloat = 0
var body: some View {
Circle()
.frame(width: 100, height: 100)
.scaleEffect(1 + scale)
.foregroundColor(.blue)
.onChange(of: throbbing) { newValue in
if newValue {
withAnimation(.easeInOut.repeatForever()) {
scale = 0.2
}
} else {
withAnimation {
scale = 0
}
}
}
}
}
There're two interesting things that i've just found when trying to achieve yours target.
Animation will be added when the value changed
Animation that added to the view cannot be removed, and we need to drop the animated view from the view hiearachy by remove its id, new view will be created with zero animations.
import SwiftUI
import PlaygroundSupport
struct ContentView: View {
#State var throbbling = false
#State var circleId = UUID()
var body: some View {
VStack {
Toggle("Throbbling", isOn: $throbbling)
circle.id(circleId)
.scaleEffect(throbbling ? 1.2 : 1.0)
.animation(.easeInOut.repeatForever(), value: throbbling)
.onChange(of: throbbling) { newValue in
if newValue == false {
circleId = UUID()
}
}
}.padding()
}
#ViewBuilder
var circle: some View {
Circle().fill(.green).frame(width: 100, height: 100)
}
}
PlaygroundPage.current.setLiveView(ContentView())
Presenting a modal sheet in SwiftUI MacOS has a nice slide in animation, but when dismissed it just disappear.
I would like to add a slide out animation to the dismissal of the sheet.
Adding the slideout on the content of the sheet obviously doesn’t work, as the content slides out, but the sheet frame remains until dismissed.
I might be missing something obvious here, but how can I add animation to the sheet itself?
struct ModalSheet: View {
#Binding var visible: Bool
#State var isShowing: Bool = true
var body: some View {
let s = "Click me to dismiss " + String(isShowing);
VStack {
Text(s)
}
.frame(width: 200, height: 100, alignment: .center)
.background(Color.green.opacity(0.5))
.onTapGesture {
isShowing.toggle()
DispatchQueue.main.asyncAfter(deadline: .now() + 0.3) {
visible.toggle()
}
}
.offset(y: self.isShowing ? 0 : CGFloat(-110)) // <-- this should be on the sheet itself
.animation(self.isShowing ? .none : .default)
}
}
struct ModalTestAnimation: View {
#State var visible: Bool = false;
var body: some View {
VStack {
Text("Click me")
.onTapGesture {
visible = true
}
}
.frame(width: 250, height: 150)
.sheet(isPresented: $visible, content: {
ModalSheet(visible: $visible)
})
}
}
I did take a look at this, but it doesn’t work for me
SwiftUI sheet not animating dismissal on macOS Big Sur
I have made a simple animation in SwiftUI which repeats forever, directly when starting the app.
However when running the code the animated circle goes to the left top and then back to its normal position while doing the rest of the animation. This top left animation is not expected and nowhere written in my code.
Sample code:
struct Loader: View {
#State var animateFirst = false
#State var animationFirst = Animation.easeInOut(duration: 3).repeatForever()
var body: some View {
ZStack {
Circle().trim(from: 0, to: 1).stroke(ColorsPalette.Primary, style: StrokeStyle(lineWidth: 3, lineCap: .round)).rotation3DEffect(
.degrees(self.animateFirst ? 360 : -360),
axis: (x: 1, y: 0, z: 0), anchor: .center).frame(width: 200, height: 200, alignment: .center).animation(animationFirst).onAppear {
self.animateFirst.toggle()
}
}
}
}
and then showing it in a view like this:
struct LoaderViewer: View {
var body: some View {
VStack {
Loader().frame(width: 200, height: 200)
}
}
I don't know exactly why this happens but I have a vague idea.
Because the animation starts before the view is fully rendered in the width an height, the view starts in the op left corner. The animation takes the starting position in the animation and the change to its normal position and keep repeating this part with the given animation. Which causes this unexpected behaviour.
I think it is a bug, but with the theory above I have created a workaround for now. In the view where we place the loader we have to wait till the parent view is fully rendered before adding the animated view (Loader view), we can do that like this:
struct LoaderViewer: View {
#State showLoader = false
var body: some View {
VStack {
if showLoader {
Loader().frame(width: 200, height: 200)
}
}.onAppear {
DispatchQueue.main.asyncAfter(deadline: .now() + 0.01) {
showLoader = true
}
}
}
}