How to cancel previous animation when a new one is triggered? - ios

I am writing a camera app, and have trouble with showing the focus square when user tap on the screen.
My code is (in swift):
self.focusView.center = sender.locationInView(self.cameraWrapper)
self.focusView.transform = CGAffineTransformMakeScale(2, 2)
self.focusView.hidden = false
UIView.animateWithDuration(0.5, animations: { [unowned self] () -> Void in
self.focusView.transform = CGAffineTransformIdentity
}, completion: { (finished) -> Void in
UIView.animateWithDuration(0.5, delay: 1.0, options: nil, animations: { () -> Void in
self.focusView.alpha = 0.0
}, completion: { (finished) -> Void in
self.focusView.hidden = true
self.focusView.alpha = 1.0
})
})
However, if use tap the screen consecutively when the previous animation does not finish, the old and new animation will mix up and the focus view will behave strangely, for example it will disappear very quick.
Could anyone tell me how to cancel previous animation, especially the previous completion block?

You can user method removeAllAnimations to stop animation
Replace your code with below
self.focusView.center = sender.locationInView(self.cameraWrapper)
self.focusView.transform = CGAffineTransformMakeScale(2, 2)
self.focusView.hidden = false
self.focusView.layer.removeAllAnimations() // <<==== Solution
UIView.animateWithDuration(0.5, animations: { [unowned self] () -> Void in
self.focusView.transform = CGAffineTransformIdentity
}, completion: { (finished) -> Void in
UIView.animateWithDuration(0.5, delay: 1.0, options: nil, animations: { () -> Void in
self.focusView.alpha = 0.0
}, completion: { (finished) -> Void in
self.focusView.hidden = true
self.focusView.alpha = 1.0
})
})
Reference : link

#Jageen solution is great, but I worked with UIStackView animation and there I needed additional steps. I have stackView with view1 and view2 inside, and one view should be visible and one hidden:
public func configureStackView(hideView1: Bool, hideView2: Bool) {
let oldHideView1 = view1.isHidden
let oldHideView2 = view2.isHidden
view1.layer.removeAllAnimations()
view2.layer.removeAllAnimations()
view.layer.removeAllAnimations()
stackView.layer.removeAllAnimations()
// after stopping animation the values are unpredictable, so set values to old
view1.isHidden = oldHideView1 // <- Solution is here
view2.isHidden = oldHideView2 // <- Solution is here
UIView.animate(withDuration: 0.3,
delay: 0.0,
usingSpringWithDamping: 0.9,
initialSpringVelocity: 1,
options: [],
animations: {
view1.isHidden = hideView1
view2.isHidden = hideView2
stackView.layoutIfNeeded()
},
completion: nil)
}

In my case, I add the focusing indicator by using addSubview().
self.view.addSubview(square)
square is the UIView I defined in the function. So when the user tap the screen to focus, this function will add a square on subview.
And to cancel this animation when the next tap happen, I just simply use the removeFromSuperview() function, when this function called it removes the view from its superview which is the focusing square here.
filterView.subviews.forEach({ $0.removeFromSuperview() })
It's different from the method above to remove the animation, but remove the subview directly.

In my case, i just needed to set the value, i animated to concrete value.
For e.g.
if ([indexPath isEqual:self.currentPlayerOrderIndexPath])
{
[UIView animateWithDuration:0.5
delay:0.0
options:UIViewAnimationOptionAutoreverse | UIViewAnimationOptionRepeat | UIViewAnimationOptionCurveEaseInOut
animations:^{
cell.avatarImageV.transform = CGAffineTransformMakeScale(1.15,1.15);
}
completion:NULL];
}
else
{
cell.avatarImageV.transform = CGAffineTransformMakeScale(1.0, 1.0);

Related

iOS stop animateWithDuration before completion

I have a CollectionView and I want to create an animation inside the CollectionViewCell selected by the user. I chose to use animateKeyframesWithDuration because I want to create a custom animation step by step. My code looks like this:
func animate() {
UIView.animateKeyframesWithDuration(1.0, delay: 0.0, options: .AllowUserInteraction, animations: { () -> Void in
UIView.addKeyframeWithRelativeStartTime(0.0, relativeDuration: 0.5, animations: { () -> Void in
// First step
})
UIView.addKeyframeWithRelativeStartTime(0.5, relativeDuration: 0.5, animations: { () -> Void in
// Second step
})
}) { (finished: Bool) -> Void in
if self.shouldStopAnimating {
self.loadingView.layer.removeAllAnimations()
} else {
self.animate()
}
}
}
This is executed inside the custom CollectionViewCell when it is selected.
The problem is that I want to force stop the animation immediately at some certain point. But when I do that, the animation doesn't fully stop, it just moves the remaining animation on a different cell (probably the last reused cell?)
I can't understand why this is happening. I have tried different approaches but none of them successfully stop the animation before normally entering the completion block
Does anyone have any idea about this?
Instead of removing the animations from the layer you could try adding another animation with a very short duration that sets the view properties that you want to stop animating.
Something like this:
if self.shouldStopAnimating {
UIView.animate(withDuration: 0.01, delay: 0.0, options: UIView.AnimationOptions.beginFromCurrentState, animations: { () -> Void in
//set any relevant properties on self.loadingView or anything else you're animating
//you can either set them to the final animation values
//or set them as they currently are to cancel the animation
}) { (completed) -> Void in
}
}
This answer may also be helpful.

UIButton shows old title after animation

Can anyone tell me why this shows the old button title for a second when reappearing?
func showSuccess(success:Bool) {
if success == true {
self.stage = 2 //needed to determine what method is triggered on button action
UIView.animateWithDuration(0.4, delay: 0.0, options: .CurveEaseOut, animations: {
self.oldView.alpha = 0
}, completion: { finished in
self.textLabel.text = "new text new text new text"
self.actionButton.setTitle("BAR", forState: .Normal)
self.reappearView(self)
})
}
}
func reappearView(sender:AnyObject) {
self.oldView.layoutIfNeeded()
UIView.animateWithDuration(0.4, delay: 0.0, options: .CurveEaseOut, animations: {
self.oldView.alpha = 1
}, completion: { finished in
})
}
For some odd reason, the text change on the label field works fine as expected. The button will animate in with it's old title, then during the reappear animation - switch to the new title set in the completion handler of showSuccess().
I also tried to move all text changes as first part of reappearView() and then trigger the 2nd animation, same outcome.

Unable to remove from superview (swift2)

I am unable to remove from superview with the following code?
Why is this?I have tried everything but seems that it is not working at all.I am adding more details so I don't get this very annoying alert that tells me that my post is mostly code....
let controller = storyboard!.instantiateViewControllerWithIdentifier("OrderViewController")
controller.view.frame = CGRectMake(self.view.frame.size.width/2 - 100, self.view.frame.size.height/2 - 100, 200, 200)
if sender.selected {
sender.selected = false
controller.view.transform = CGAffineTransformIdentity
[UIView .animateWithDuration(0.2, delay: 0.0, options: UIViewAnimationOptions.CurveEaseOut, animations: {
controller.view.transform = CGAffineTransformMakeScale(0.01, 0.01);
}, completion: { finished in
controller.willMoveToParentViewController(nil)
controller.view .removeFromSuperview()
controller.removeFromParentViewController()
})]
print("close")
}
else {
sender.selected = true
addChildViewController(controller)
view.addSubview(controller.view)
controller.didMoveToParentViewController(self)
controller.view.transform = CGAffineTransformMakeScale(0.01, 0.01);
[UIView .animateWithDuration(0.2, delay: 0.0, options: UIViewAnimationOptions.CurveEaseOut, animations: {
controller.view.transform = CGAffineTransformIdentity
}, completion: nil)]
print("present")
}
There's a weird mix of objective-c syntax (the square brackets around your UIView animation block) and swift. I'm surprised if this is even compiling without errors!
You're almost there, the main issue is that each time this block of code is called you're instantiating a new instance of an 'OrderViewController'.
You only want to create this if it doesn't exist (when you want to show it). When you're ready to hide it you want to grab a reference to the existing controller and do the animations etc to hide it.
To do that you'll need to keep a reference to it outside of the local scope of that code block.
Here's an example showing how you might do that:
import UIKit
class ViewController: UIViewController {
// keep a reference to the OrderViewController after it's been created
var controller:UIViewController?
#IBAction func buttonTapped(sender: AnyObject) {
// instead of using button selected state, just check to see if
// self.controller is nil or not
if let existingController = self.controller {
// controller already exists, lets hide it
existingController.view.transform = CGAffineTransformIdentity
UIView.animateWithDuration(0.2, delay: 0.0, options: UIViewAnimationOptions.CurveEaseOut, animations: {
existingController.view.transform = CGAffineTransformMakeScale(0.01, 0.01);
}, completion: { _ in
existingController.willMoveToParentViewController(nil)
existingController.view.removeFromSuperview()
existingController.removeFromParentViewController()
// make this nil, so that next time the button is
// tapped we'll go though the process of creating it again
self.controller = nil
})
print("close")
}
else {
// controller doesn't exist, lets instanstiate and show it
let newController = storyboard!.instantiateViewControllerWithIdentifier("OrderViewController")
newController.view.frame = CGRectMake(self.view.frame.size.width/2 - 100, self.view.frame.size.height/2 - 100, 200, 200)
addChildViewController(newController)
view.addSubview(newController.view)
newController.didMoveToParentViewController(self)
newController.view.transform = CGAffineTransformMakeScale(0.01, 0.01)
UIView.animateWithDuration(0.2, delay: 0.0, options: UIViewAnimationOptions.CurveEaseOut, animations: {
newController.view.transform = CGAffineTransformIdentity
}, completion: { _ in
// keep a reference to this controller you've just created,
// so that next time the button is tapped you can close it
self.controller = newController
})
print("present")
}
}
}
If you're working on a really simple app (just a couple of screens) then this method is okay.
But.... if you're planning on something more complex you might want to investigate using either a custom UISegue, or a mix of UIPresentationController and UIViewControllerAnimatedTransitioning so that all of this animation logic doesn't get locked into your view controller code.

How do I change the text of a UILabel between each animation of animateWithDuration with repeat?

I have an Array words containing ["alice", "bob", "charles"] and a UILabel label. I want label to repeatedly fade in and out, with a different word from words each time. If I put the text-changing code inside the animations block, it doesn’t execute, even though the fading works as expected (the completion block is run only when something stops the repetition):
label.alpha = 0
UIView.animateWithDuration(4, delay: 0, options: .Autoreverse | .Repeat, animations: {
self.label.text = nextWord()
self.label.alpha = 1
}, completion: {_ in
NSLog("Completed animation")
})
What’s a good way to fix this? Thanks.
surely not the most elegant but working solution:
#IBOutlet weak var label: UILabel!
let words = ["Is", "this", "what", "you", "want?"]
var currentIndex = -1
override func viewDidAppear(animated: Bool) {
super.viewDidAppear(animated)
showNextWord()
}
func showNextWord() {
if currentIndex == words.count - 1 {
currentIndex = -1
}
UIView.animateWithDuration(1, delay: 1, options: UIViewAnimationOptions(0), animations: { () -> Void in
self.label.alpha = 0.0
}) { (_) -> Void in
self.label.text = self.words[++self.currentIndex]
UIView.animateWithDuration(1, animations: { () -> Void in
self.label.alpha = 1.0
}, completion: { (_) -> Void in
self.showNextWord()
})
}
}
You could construct this as a keyframe animation. That way, you can chain three animations together (one for each word) and repeat that entire chain.
Alternatively (this is what I would probably do), put one animation into a method of its own, and in the completion block, add a short delay and call the method - thus creating a perpetual loop. The loop creates the repetition, but each animation is just one animation, so now you can progress through the array on successive calls. So the structure (pseudo-code) would look like this:
func animate() {
let opts = UIViewAnimationOptions.Autoreverse
UIView.animateWithDuration(1, delay: 0, options: opts, animations: {
// animate one fade in and out
}, completion: {
_ in
delay(0.1) {
// set the next text
self.animate() // recurse after delay
}
})
}

using animatewithduration to move image view

I am trying to move an image multiple times. This is how i tried implementing it.
override func viewDidAppear(animated: Bool) {
UIView.animateWithDuration(1, animations: { () -> Void in
self.sattelite.center.x = 50
self.sattelite.center.y = 100
self.sattelite.center.x = 50
self.sattelite.center.y = 50
self.sattelite.center.x = 50
self.sattelite.center.y = 300
})
}
The animatewithduration method however only executes one of the movements. Is there any way to animate all three movements of the image view? Thanks.
you can easily chain animations ; start another at completion :
Here an illustration :
//1st animation
UIView.animateWithDuration(1.0,
delay: 0.0,
options: .CurveEaseInOut | .AllowUserInteraction,
animations: {
//some code ex : view.layer.alpha = 0.0
},
completion: { finished in
//second animation at completion
UIView.animateWithDuration(1.0
, delay: 0.0,
, options: .CurveEaseInOut | .AllowUserInteraction,
, animations: { () -> Void in
//some code ex : view.layer.alpha = 1.0
}
, completion: { finished in
//third animation at completion
UIView.animateWithDuration(1.0,
delay: 0.0,
options: .CurveEaseInOut | .AllowUserInteraction,
animations: {
//some code ex : view.layer.alpha = 0.0
},
completion: { finished in
//FINISH : 3 animations!!!
})
})
})
You need to either chain the animations with completion or use a Key Frame animation
Use the animation version which has completion:
class func animateWithDuration(_ duration: NSTimeInterval,
animations animations: () -> Void,
completion completion: ((Bool) -> Void)?)
Do the first animation only on animations and start the second in the completion. The third goes in the completion of the second.
So basically a chain of animations, where each starts when the previous finishes.

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