I'm making a custom BottomSheetController, whose height is dynamic and is set inside the controller using the preferredContentSize property. How do I calculate the duration of the animation depending on the height of the content so that the animation always looks smooth?
Demo - https://www.youtube.com/watch?v=FVYbUdDLI9g
internal class PresentAnimation: NSObject, UIViewControllerAnimatedTransitioning {
func transitionDuration(
using context: UIViewControllerContextTransitioning?
) -> TimeInterval {
context!.view(forKey: .to)!.frame.height * 0.002
}
func animateTransition(using context: UIViewControllerContextTransitioning) {
let to = context.view(forKey: .to)!
let finalFrame = context.finalFrame(
for: context.viewController(forKey: .to)!
)
var frameWithOffset = finalFrame
frameWithOffset.origin.y = context.containerView.frame.height
to.frame = frameWithOffset
UIView.animate(
withDuration: transitionDuration(using: context),
delay: 0,
usingSpringWithDamping: 1,
initialSpringVelocity: 0,
options: .curveEaseInOut,
animations: {
to.frame = finalFrame
},
completion: { _ in
context.completeTransition(true)
}
)
}
I would suggest clamping the animation time to some bounds like min 0.2 and max 0.5. Also adjust the spring damping and velocity for different heights. As the very small view shouldn't bounce with the same energy as bigger one (at least that way it will look more natural)
You can read more about them from this tutorial:
https://www.hackingwithswift.com/example-code/uikit/how-to-animate-views-with-spring-damping-using-animatewithduration
Related
I'm playing around with custom and interactive view controller transistion, with UIPercentDrivenInteractiveTransition. I'm building an app that present a card (other view controller) modally. I've made custom transistions with UIViewControllerAnimatedTransitioning that is animating the card view controller a lot like the standart model presentation style.
func animateTransition(using transitionContext: UIViewControllerContextTransitioning) {
{...}
let fullScreenFrame = transitionContext.finalFrame(for: cardVC)
let offsetFrame = cardVC.view.frame.offsetBy(dx: 0, dy: cardVC.view.frame.height)
let finalFrame = presenting ? fullScreenFrame : offsetFrame
cardVC.view.frame = presenting ? offsetFrame : fullScreenFrame
containerView.addSubview(cardVC.view)
UIView.animateKeyframes(
withDuration: transitionDuration(using: transitionContext),
delay: 0,
options: UIViewKeyframeAnimationOptions.calculationModeLinear,
animations: {
UIView.addKeyframe(
withRelativeStartTime: 0,
relativeDuration: 1,
animations: { [weak self] in
guard let strongSelf = self else { return }
backgroundView.alpha = strongSelf.presenting ? 1 : 0
})
UIView.addKeyframe(
withRelativeStartTime: 0,
relativeDuration: 1,
animations: {
cardVC.view.frame = finalFrame
})
}, completion: { finished in
backgroundView.removeFromSuperview()
gradientView.alpha = 1
transitionContext.completeTransition(!transitionContext.transitionWasCancelled)
})
}
And then I use a pan gesture recognizer to interactively drive the dismiss animation:
func handleGesture(_ gestureRecognizer: UIScreenEdgePanGestureRecognizer) {
let translation = gestureRecognizer.translation(in: gestureRecognizer.view)
var progress = (translation.y / (UIScreen.main.bounds.height - 70))
progress = CGFloat(fminf(fmaxf(Float(progress), 0.0), 1.0))
switch gestureRecognizer.state {
case .began:
interactionInProgress = true
viewController.dismiss(animated: true, completion: nil)
case .changed:
shouldCompleteTransition = progress > 0.35
update(progress)
case .cancelled:
interactionInProgress = false
cancel()
case .ended:
interactionInProgress = false
if !shouldCompleteTransition {
cancel()
} else {
finish()
}
default:
print("Unsupported")
}
}
When I dismiss the presented view controller by dragging it down, it doesn't seem to move linearly with the gesture. It seems like the Interaction Controller is using some easeInEaseOut function. Maybe setting UIPercentDrivenInteractiveTransition's timingCurve to make the transition run linearly. Is that posible, or am I getting something wrong?
You yourself have given the animation a default ease in - ease out timing curve, by not setting the timing curve to anything different in your call to UIView.animateKeyframes. That applies even during interaction.
Note that setting the animation's options to UIViewKeyframeAnimationOptions.calculationModeLinear does not change the timing curve (in case that's what you thought you were accomplishing here). The way to add a linear timing curve to a linear calculation mode keyframe animation is like this:
var opts : UIViewKeyframeAnimationOptions = .calculationModeLinear
let opt2 : UIViewAnimationOptions = .curveLinear
opts.insert(UIViewKeyframeAnimationOptions(rawValue:opt2.rawValue))
// and now use `opts` as your `options`
I was having the same issue, was able to set a custom animation curve for animateKeyframes using UIView.setAnimationCurve like this:
UIView.animateKeyframes(withDuration: 4, delay: 0, options: [], animations: {
UIView.setAnimationCurve(.linear)
UIView.addKeyframe(withRelativeStartTime: 0, relativeDuration: 0.24, animations: {
// Animations...
})
// Other key frames...
})
In my case, It works with interruptibleAnimator(using:) by return UIViewPropertyAnimator
I'm trying to hide UIStackView's subview like this:
UIViewPropertyAnimator.runningPropertyAnimator(withDuration: 2.0,
delay: 0, options: [.curveEaseOut], animations: {
self.label.isHidden = true
self.label.alpha = 0.0
self.stackView.layoutIfNeeded()
})
However, the label disappears instantly with using this code. I suspect this is because of setting isHidden to true, which is required for collapsing.
Is there a way how to hide and collapse UIStackView's subvew with animation? Or it might be better to not to use UIStackView at all?
According to Apple's documentation:
You can animate both changes to the arranged subview’s isHidden property and changes to the stack view’s properties by placing these changes inside an animation block.
I've tested the below code using iOS 12.1 Simulator and it works as expected.
UIView.animate(
withDuration: 2.0,
delay: 0.0,
options: [.curveEaseOut],
animations: {
self.label.isHidden = true
self.label.alpha = 0.0
})
You can animate view properties like alpha, color, etc. However, some things happen instantly - isHidden in this case.
Here's an example using UIView.animate:
UIView.animate(withDuration: 2, delay: 0, options: .curveEaseOut, animations: {
self.label.alpha = 0 // Changes the label's layer alpha value
}, completion: { finished in
self.label.isHidden = true // Hides the label
self.label.layer.alpha = 1 // Resets the label's alpha without un-hiding it
})
Using UIViewPropertyAnimator:
UIViewPropertyAnimator.runningPropertyAnimator(withDuration: 2, delay: 0, options: .curveEaseOut, animations: {
self.label.alpha = 0 // Sets the label's alpha
}) { _ in
self.label.isHidden = true // Hides the label
self.label.alpha = 1 // Resets the label's alpha without un-hiding it
}
I have tried your code. Its animating
if self.stackView.subviews.count > 0 {
UIViewPropertyAnimator.runningPropertyAnimator(withDuration: 1.0, delay: 0, options: [.curveEaseOut], animations: {
self.stackView.subviews[0].isHidden = true
self.stackView.subviews[0].alpha = 0.0
self.stackView.layoutIfNeeded()
}) { (position) in
self.stackView.subviews[0].removeFromSuperview()
}
}
Just you can use simple solution with animateKeyframes to fade alpha , then hide , i think this will give you what you need So hide after 1 Sec and 0.8 Sec fading
// showLabel is Bool to handle status declare it at you File
#IBAction func toggleStackLabelTapped(_ sender: UIButton) {
showLabel = !showLabel
UIView.animateKeyframes(withDuration: 1, delay: 0, options: .calculationModeLinear, animations: {
UIView.addKeyframe(withRelativeStartTime: 0, relativeDuration: 0.8) {
self.label.alpha = (self.showLabel) ? 1 : 0
}
UIView.addKeyframe(withRelativeStartTime: 0.8, relativeDuration: 1) {
self.label.isHidden = !self.showLabel
}
})
}
make sure you have not given height constraint to the stackview.
and try this.
UIView.animate(withDuration: 0.5) {
self.stackView.subviews[INDEX_OF_LABEL_IN_STACK]?.alpha = 0
self.stackView.subviews[INDEX_OF_LABEL_IN_STACK]?.isHidden = true
self.view.layoutSubviews()
}
I am adding and removing attributed text from a UITextView. I wish to use UIView.animate to add an animation to when text is appended to the text view and when that appended text is removed from the text view. So far, I have this, but it does not cause any noticeable animation on the text view:
UIView.animate(withDuration: 1, delay: 0, options: .CurveLinear, animations: {
self.view.layoutIfNeeded()
self.textView.attributedText = newAttributedText
}, completion: { finished in
print("Animation completed")
}
// prints "Animation completed", but no animation occurs
You cannot animate changing of text in that manner. There is a list of animatable properties of CALayer class and UIView class.
Set text cannot be animated by UIView.animate. Only changes like transparency, colors, shape, location, etc can be animated by the UIView.animate.
Here is an example of animating origin and transparency change with code looks like
self.textView.text = "test Animation"
self.textView.alpha = 0
UIView.animate(withDuration: 3, delay: 0, options: .curveLinear, animations: {
var frame = self.textView.frame
frame.origin.x = frame.origin.x + 50
frame.origin.y = frame.origin.y + 50
self.textView.frame = frame
self.textView.alpha = 1
}, completion: { finished in
print("Animation completed")
})
And animation looks like
Here is my solution (swift 3 ) :
let animator = UIViewPropertyAnimator(duration: 0.2, curve: .easeOut, animations: {
self.textView2.frame = self.textView2.frame.offsetBy(dx: 20 , dy: 25)
} )
animator.startAnimation()
I have a UIView that I want to reveal after 0.5 seconds, and hide again after 0.5 seconds, creating a simple animation. My code is as follows:
let animation = UIViewPropertyAnimator.init(duration: 0.5, curve: .linear) {
self.timerBackground.alpha = 1
let transition = UIViewPropertyAnimator.init(duration: 0.5, curve: .linear) {
self.timerBackground.alpha = 0
}
transition.startAnimation(afterDelay: 0.5)
}
animation.startAnimation()
When I test it out, nothing happens. I assume it's because they're both running at the same time, which would mean they cancel each other out, but isn't that what the "afterDelay" part should prevent?
If I run them separately, i.e. either fading from hidden to visible, or visible to hidden, it works, but when I try to run them in a sequence, it doesn't work.
My UIView is not opaque or hidden.
You can use Timer, and add appearing / hiding animations blocks on every timer tick to your UIViewPropertyAnimatorobject.
Here's a codebase:
#IBOutlet weak var timerBackground: UIImageView!
private var timer: Timer?
private var isShown = false
private var viewAnimator = UIViewPropertyAnimator.init(duration: 0.5, curve: .linear)
override func viewDidLoad() {
super.viewDidLoad()
viewAnimator.addAnimations {
self.timerBackground.alpha = 1
}
viewAnimator.startAnimation()
isShown = true
self.timer = Timer.scheduledTimer(timeInterval: 0.5, target: self, selector: #selector(self.startReversedAction), userInfo: nil, repeats: true)
}
func startReversedAction() {
// stop the previous animations block if it did not have time to finish its movement
viewAnimator.stopAnimation(true)
viewAnimator.addAnimations ({
self.timerBackground.alpha = self.isShown ? 0 : 1
})
viewAnimator.startAnimation()
isShown = !isShown
}
I've implemented the very similar behavior for dots jumping of iOS 10 Animations demo project.
Please, feel free to look at it to get more details.
Use UIView.animateKeyframes you'll structure your code nicely if you have complicated animations. If you'll use UIView animations nested within the completion blocks of others, it will probably result in ridiculous indentation levels and zero readability.
Here's an example:
/* Target frames to move our object to (and animate)
or it could be alpha property in your case... */
let newFrameOne = CGRect(x: 200, y: 50, width: button.bounds.size.width, height: button.bounds.size.height)
let newFrameTwo = CGRect(x: 300, y: 200, width: button.bounds.size.width, height: button.bounds.size.height)
UIView.animateKeyframes(withDuration: 2.0,
delay: 0.0,
options: .repeat,
animations: { _ in
/* First animation */
UIView.addKeyframe(withRelativeStartTime: 0.0, relativeDuration: 0.5, animations: { [weak self] in
self?.button.frame = newFrameOne
})
/* Second animation */
UIView.addKeyframe(withRelativeStartTime: 0.5, relativeDuration: 0.5, animations: { [weak self] in
self?.button.frame = newFrameTwo
})
/* . . . */
}, completion: nil)
What worked for me, was using sequence of UIViewPropertyAnimators. Here is example of my code:
let animator1 = UIViewPropertyAnimator(duration:1, curve: .easeIn)
animator1.addAnimations {
smallCoin.transform = CGAffineTransform(scaleX: 4, y: 4)
smallCoin.center = center
}
let animator2 = UIViewPropertyAnimator(duration:1, curve: .easeIn)
animator2.addAnimations {
center.y -= 20
smallCoin.center = center
}
let animator3 = UIViewPropertyAnimator(duration:10, curve: .easeIn)
animator3.addAnimations {
smallCoin.alpha = 0
}
animator1.addCompletion { _ in
animator2.startAnimation()
}
animator2.addCompletion { _ in
animator3.startAnimation()
}
animator3.addCompletion ({ _ in
print("finished")
})
animator1.startAnimation()
You can even add afterdelay attribute to manage speed of animations.
animator3.startAnimation(afterDelay: 10)
To animate a bar opening...
#IBOutlet var barHeight: NSLayoutConstraint!
barHeight.constant = barShut?30:100
self.view.layoutIfNeeded()
t = !barShut?30:100
UIView.animate(withDuration: 0.15,
delay: 0,
options: UIViewAnimationOptions.curveEaseOut,
animations: { () -> Void in
self.barHeight.constant = t
self.view.layoutIfNeeded()
},
completion: {_ in
Screen.barShut = !Screen.barShut
}
)
That's great ...
But how would you make it boing like this?
(The only way I'd know to do this is, use CADisplayLink, with a few lines of code for a spring decaying.) Is this available in UIKit?
You can use the spring animation method that is built in to UIView:
func toggleBar() -> Void {
self.view.layoutIfNeeded()
let newHeight:CGFloat = !barShut ? 30:100
barShut = !barShut
barHeightConstraint.constant = newHeight
UIView.animate(withDuration: 1.5, delay: 0, usingSpringWithDamping: 0.2, initialSpringVelocity: 3, options: [], animations: {
self.view.layoutIfNeeded()
}, completion: nil)
}
You will want a longer animation duration than 0.15 of a second in order for the bounce to seem realistic; I think the values I have look pretty good, but you can play with them to get the exact effect you are after.
Since the animation duration is longer, I found that I could tap the button the triggered the open/shut while the previous animation was still running. Setting barShut in the completion block meant that the bar didn't react to all taps. I moved the toggle outside of the animation to address this.