Building Card-Highlighting-Animation as in the App-Store - ios

In the AppStore (iOS 11) on the left "today"-tab, there are several card views. If you highlight one, it shrinks a little bit. How can I rebuild this animation?
I guess changing the constraints of the card view during an animation will not be what we need, since you would also have to adapt all the other constraints (e.g. of the labels) to match the new size.
Is there an easier way to shrink a view with all its subviews?
Also, when you click the card, it increases to fullscreen with an animation. Do you have any ideas how to achieve this effect?

For tapping and shrinking card, I also wrote about this in detail. Here's the idea:
Use a scaling transform to animate shrinking (like in accepted answer)
Disable delaysContentTouch to make it shrink faster upon touch
(scrollView.delaysContentTouch = false)
Always allow users to scroll using .allowUserInteraction animation option:
UIView.animate(withDuration: 1.0,
delay: 0.0,
options: [.allowUserInteraction],
animations: ...,
completion: ...)
(By default when you use transform, it disables the interaction a bit. User can't scroll successively without doing that)
About the expanding to full screen with animation, I have tried to replicate it with the native's transition APIs which you can check out here: https://github.com/aunnnn/AppStoreiOS11InteractiveTransition
In short, I use UIViewControllerAnimatedTransitioning to do custom animation. Hide the original card and create a new dummy card view just for animation. Then setup AutoLayout constraints of that card, including 4 to each of the screen edges. Then animate those constraints to make it fill the screen.
After everything is done, hide that dummy view and show the destination detail page.
Note: The exact implementation detail is a bit different and involved.

You can get an easy scale animation using transform:
UIView.animate(withDuration: 0.2) {
view.transform = CGAffineTransform.identity.scaledBy(x: 0.9, y: 0.9)
}
As to the fullscreen animation, you want to check out some tutorials on how to create custom transition animations.

If you are interested in a more complete functionality you can use this library:
https://github.com/PaoloCuscela/Cards

this is also a good rebuild of that animation when you press a card:
UIView.animate(withDuration: 0.5, delay: 0.0, usingSpringWithDamping: 0.8, initialSpringVelocity: 0.8, options: .beginFromCurrentState, animations: {
self.transform = .init(scaleX: 0.95, y: 0.95)
}, completion: nil)

Related

Why do these constraints seem to lag when animated?

I am animating my constraints using UIView.animate. drawerHeight is a constraint variable.
Here is the code:
drawerHeight?.constant = newHeight
UIView.animate(withDuration: 0.35, delay: 0, usingSpringWithDamping: 0.65, initialSpringVelocity: 2, options: .allowUserInteraction, animations: {
self.superview?.layoutIfNeeded()
})
Here is a video of what the issue looks like.
Looking at the bottom of the video, the bottom edge appears to lag behind. Why do these constraints seem to lag when animated?
This is a self-answered question. This post is to help people in the future discover what they did wrong, and how to quickly fix it.
The issue was that the constraint was attached to a view in a deeper hierarchy than before. When using layoutIfNeeded(), it should be called on the superview of the view containing the constraints.
In my situation, I put the view with the drawerHeight constraint within another UIView, which made it deeper in the hierarchy.
I fixed the issue by doing
self.superview?.superview?.layoutIfNeeded() ,
instead of
self.superview?.layoutIfNeeded() .

How to do interactive transition + ending animation?

Normally, we can do an interactive transitioning with animateTransition of UIViewControllerAnimatedTransitioning and updating progress via UIPercentDrivenInteractiveTransition.
Question:
How to have the interactive transitioning at first, then as we pass a certain threshold, perform a different ending animation?
What I want to achieve here is something like dismissing App store's Today card (https://gph.is/2qgcGHd). We can interactively shrink the card by panning a left edge of the screen. Then when it reaches the point, the card animates back to home page without any interactivity. It seems like a combination of interactive + animate transition to me.
What I've tried:
I tried doing this in UIView.animateWithKeyFrames by dividing into two parts of animation with 0.5 relative times for each. Then as the progress reach 0.5, I call finish() (of UIPercentDrivenInteractiveTransition) to have the second animation performing. It has some glitches there and it's like a hack. Want to know if there's a better way to do this.
In the end, I use UIView.animateKeyFramesand dividing the interactive transition into two-part animation (as explained in the question):
let progressUntilDismissing = 0.4
UIView.animateKeyframes(withDuration: 0.5, delay: 0, options: [], animations: {
UIView.addKeyframe(withRelativeStartTime: 0.0,
relativeDuration: progressUntilDismissing,
animations: {
// interactive dismissing animation...
})
UIView.addKeyframe(withRelativeStartTime: progressUntilDismissing,
relativeDuration: (1 - progressUntilDismissing),
animations: {
// closing dismissing animation...
})
}) { (finished) in
//...
}
Then in the pan gesture recognizer, I calculate the pan progress and determine if it passes progressUntilDismissing or not.
If yes, call finish() on UIPercentDrivenInteractiveTransition subclass, it will animate the closing dismissing animation automatically.
In case anyone is curious, this is what I'm playing with:
AppStoreTodayInteractiveTransition

Show No Internet Connection Message Like Instagram

I was wondering how can i show a 'No Internet Connection' Just how like Instagram does it,
As an Example :
That see-through custom message animating to show under the navigationController . Would really love to get this to my project ,
thank you for you help
So here's a pic of the storyboard like this :-
"No internet connection" is a label, and the red view underneath is just to test the see through property of the label. If you are designing the UI in code, you can probably make a label similar to mine and place it to the top of the Navigation bar by using it's frame property.
The button here I'm using is just to show the label pop up on the scene (since it's just a demo answer). In your case, if the internet is not available, you will proceed to show the pop up.
So if you are making the UI in code, make sure to make the label in the viewDidLoad method. I have made an IBOutlet and the viewDidLoad now looks like this:-
override func viewDidLoad() {
super.viewDidLoad()
let transform = CGAffineTransform(translationX: 0, y: -label.frame.height)
label.alpha = 0
label.transform = transform
}
On the view loading, I'm moving the label behind the navigation bar, using CGAffineTransform. The distance, how much to move up is the label's height, since we don't want any part to be clipped on the scene.
Next step, is just a fix. I'm making alpha = 0, because navBar is translucent is nature and hence will change it's colour, since our label is behind it. So setting alpha to 0, takes care of it, and in third step apply the transform.
Now, if the internet connection is not available, we should pop out the label under the navBar. The code will look something like this:-
fun checkInternet() {
// called by some of your observer, which checks for changes in internet connection
if !isInternetAvailable {
UIView.animate(withDuration: 0.5, delay: 0, usingSpringWithDamping: 0.3, initialSpringVelocity: 0, options: .curveLinear, animations: {
self.label.alpha = 0.5
self.label.transform = .identity
}, completion: nil)
}
}
So here, I'll show the pop up with an animation using UIView.animate with some spring damping, so it has a nice bouncy effect to it. I'm setting the alpha to 0.5, since you mentioned you want a see through label, and I'm setting the label to a transform which will bring it back to it's original position when it was created, that's why I'm using .identity.
You can play around usingSpringWithDamping values and change options to have different effects.

Can I force an element to finish it's animation immediately?

Here I have some code to show a UIView with a label as a notification.
self.not1cons.constant = 0
self.notificationLbl1.text = self.notification1
UIView.animate(withDuration: 2.5, delay: 0.3, options: .allowAnimatedContent, animations: {
self.view.layoutIfNeeded()
}, completion: { finsihed in
self.not1cons.constant = -100
UIView.animate(withDuration: 2.5, delay: 2.0, options: .allowAnimatedContent, animations: {
self.view.layoutIfNeeded()
}, completion: { finshed in
})
})
It start off-screen and descends in to view. It stays in place for a few seconds and returns to its original position off-screen. I need some code to make these chained animations happen instantly. Is this possible?
You could probably accomplish this by manipulating the CAAnimations the system generates behind the scenes, but that is fairly tricky business, and not a great idea since it relies on undocumented details of the current implemention, which is risky.
Instead I'd suggest reworking your animations to use the new-to-iOS 10
UIViewPropertyAnimator, which has support for pausing and resuming animations, as well as scrubbing them back and forth to arbitrary points.
I have a demo project on Gitub called UIViewPropertyAnimator-test that lets you scrub an animation back and forth using a slider. It is more complex than your need, but it should give you the idea.

Difficulty allowing user interaction during UIView animation

I'm struggling to figure out how to allow user interaction with a view as it's being animated.
Here's the situation: I have a UIView cardView which holds card subviews. The cards are draggable tiles, similar to how the cards in Tinder are draggable/swipeable.
I am trying to fade out the card using animateWithDuration by animating to cardView.alpha = 0. Logically, this will also fade out all of the subviews (card objects). In this specific case, I am only targeting one card subview. However, during the animation, I am unable to drag/interact with the card.
Here is the code I'm using:
UIView.animateWithDuration(
duration,
delay: 0,
options: UIViewAnimationOptions.AllowUserInteraction,
animations: {self.cardView.alpha = 0}
) {
_ in
println("Card faded out")
card.removeFromSuperview()
}
Why doesn't this work? Any help will be appreciated. Thank you!!
I think you can find the answer in this previous post.
The interesting bit of the post is:
UIView's block animation by default blocks user interaction, and to get around it you need to pass UIViewAnimationOptionAllowUserInteraction as one of the options.
I fixed this problem by setting alpha to 0.1 instead of 0.0. I'm not sure if that will work in your case, but it shows that the event handling code thought that the view was not visible and disabled interaction even with the UIViewAnimationOptionAllowUserInteraction flag set. Oddly, setting the alpha to 0.01 did not work, so there is a threshold of visibility you have to stay above.
Swift 5
UIView.animateKeyframes(withDuration: 0.5, delay: 0, options: [.repeat, .autoreverse, .allowUserInteraction], animations: {
self.customButton.backgroundColor = .none
}, completion: nil)
The issue is with the Alpha value of 0. Alpha values of a certain proximity to Zero will remove the view from the view responder hierarchy. The fix here is to make the alpha setting to this:
self.cardView.alpha = 0.011
The view will still be invisible but not removed from the responder chain. From my testing the minimum amount is the following:
extension CGFloat {
static let minAlphaForTouchInput: CGFloat = 0.010000001
}

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