I am trying to animate the height change for a collection view, but I can't figure out how to get the animation to work. The height changes correctly, but it happens immediately, not animated.
#IBOutlet weak var collectionViewHeight: NSLayoutConstraint!
UIView.animateWithDuration(0.3, delay: 0, options: .CurveEaseOut, animations: {
self.collectionViewHeight.constant = 0
}
I tried searching for solutions, but couldn't find anything specific to this situation. Also tried layoutIfNeeded() suggested here, but it didn't help: Animate view height with Swift
Any help much appreciated!
You should update the constant of the constraint outside of the animation block:
self.collectionViewHeight.constant = 0
UIView.animateWithDuration(0.3, delay: 0, options: .CurveEaseOut,
animations: view.layoutIfNeeded, completion: nil)
(view is the superview of the collection view in question.)
Related
I'm trying to show a UICollectionView in a UITableViewCell. Initially the CollectionView shouldn't be shown, but when the users presses a button the CollectionView should become visible with an animation. I got this working however the first time the CollectionView becomes visible it looks like the cells get zoomed out, if I hide the CollectionView and expand it again, the animation looks correct:
http://g.recordit.co/DBhZCmJKPj.gif
This is the code for animation the change:
func expand() {
tableView?.beginUpdates()
UIView.animate(withDuration: 0.3, delay: 0.0, options: .curveLinear, animations: {
self.imageViewDisclosureIndicator.setImage(UIImage(named: "arrow-up"), for: .normal)
self.collectionViewHeight.constant = self.collectionView.intrinsicContentSize.height
self.layoutIfNeeded()
self.isExpanded = true
}, completion: nil)
tableView?.endUpdates()
}
func collapse() {
tableView?.beginUpdates()
UIView.animate(withDuration: 0.3, delay: 0.0, options: .curveLinear, animations: {
self.imageViewDisclosureIndicator.setImage(UIImage(named: "arrow-down"), for: .normal)
self.collectionViewHeight.constant = CGFloat(0.0)
self.layoutIfNeeded()
self.isExpanded = false
}, completion: nil)
tableView?.endUpdates()
}
Any help would be appreciated!
Try putting self.layoutIfNeeded outside the animation.
Based off your code, I don't see why you need that line of code, but it is probably the cause for your problem. I think that the content would even load fine without that line, because the size of the content view of the collection view is independent of the height of the collection view.
I want to animate a view like using the following code:
UIView.animate(withDuration: 2.7, delay: 0.1, options: .allowAnimatedContent, animations: {
self.AVCenterY.constant = 0.8
}, completion: nil)
But it happens so fast it seems like it is not animated. On the other hand, when I animate the property alpha it is animated (it takes the 2.7 seconds to change). I used 2.7 sec to make sure the problem was that I was using a small duration time.
Constraints cannot be animated at all. It is the act of layout that can be animated:
UIView.animate(withDuration: 2.7, delay: 0.1, options: .allowAnimatedContent, animations: {
self.AVCenterY.constant = 0.8
theView.superview?.layoutIfNeeded() // *
}, completion: nil)
When we animate the act of layout (or when the runtime does so), then any constraint changes are also automatically animated.
Note that what I animate is the layout of the superview of the view that is to move. I called it theView but that is just something I made up. You will need an outlet to that view so that you can get its superview, and use the name of that outlet.
I have a UIStackView with 5 subviews. I want to be able to animate the width of these subviews by updating their intrinsicContentSize or updating their constraints. How can I make the stackView redraw after updating the subview's layout?
UIView.animateWithDuration(0.3, animations: {
viewToResize.compressed = true //changes intrinsicContentSize
viewToResize.invalidateIntrinsicContentSize()
self.stackView.layoutIfNeeded() //makes no difference
anotherSubview.hidden = true //adding this makes everything work
})
I have tried various ways of trying to get the stackView to update, but nothing happens. The only way I can make it work is if I show/hide another subview inside the animation block, then the new layout is animated correctly, but I don't want to do this.
I have seen this question
Animating UIStackView arrangedSubview content size change
but the suggested answer does not work (nothing animates).
You don't need viewToResize.invalidateIntrinsicContentSize(), update constraint of your subviews instead. In the code below, we have two subviews in the stackView, and we create a widthConstraint outlet from storyboard. Then we can animate the width of the subview by updating the constant of widthConstraint in animation block. Note: If a view is contained in a stack view and you try to modify the view frame, it should not change
class ViewController: UIViewController {
#IBOutlet var widthConstraint: NSLayoutConstraint!
#IBOutlet var stackView: UIStackView!
var compressed: Bool = true
#IBOutlet var start: UIButton!
#IBAction func onStart(sender: UIButton) {
UIView.animateWithDuration(3.0,
delay: 0.0,
usingSpringWithDamping: 0.3,
initialSpringVelocity: 10.0,
options: .CurveLinear,
animations: { () -> Void in
//self.stackView.invalidateIntrinsicContentSize()
self.widthConstraint.constant = (self.compressed == false) ? 100.0 : 200.0
self.compressed = !self.compressed
self.view.layoutIfNeeded()
}, completion: nil)
}
For more details, you can have a look at this great blog UIStackView, Auto Layout and Core Animation
I am hiding my navigation bar and a UIView under it that acts as a extension bar to it when I scroll my page.
My app is built like:
VC that holds a container view with an embedded table view.
From the table view I have delegates that notify VC1 once a user scrolls up or down.
My problem now is that the animation dont looks that good. What I am trying to do is to animate the extension bar to animate up or down with a fade in or fade out effect as well. When that occurs I also update the top contraint on my container view so that the table view will fill the whole screen. (I am not sure if I use layoutneeded() right or if something else should be used when updating constraints)
My code:
func ContainerTableViewControllerScrolledUp(controller: ContainerTableViewController) {
self.navigationController?.setNavigationBarHidden(false, animated: true)
println("UP")
UIView.animateWithDuration(
1.5,
delay: 0,
usingSpringWithDamping: 0.7,
initialSpringVelocity: 0.5,
options: nil,
animations: {
self.extensionV.alpha = 1
self.tableVConst.constant = 0
}, completion: { finished in
self.view.layoutIfNeeded()
}
)
}
func ContainerTableViewControllerScrolledDown(controller:ContainerTableViewController) {
self.navigationController?.setNavigationBarHidden(true, animated: true)
println("DOWN")
UIView.animateWithDuration(
1.5,
delay: 0,
usingSpringWithDamping: 0.7,
initialSpringVelocity: 0.5,
options: nil,
animations: {
self.extensionV.frame.origin.y = CGFloat(-10)
self.tableVConst.constant = -41
self.extensionV.alpha = 0
}, completion: { finished in
self.view.layoutIfNeeded()
}
)
}
extensionV is the extension view
tableVConst is the top constraint for my container view that holds my table view
So how should I edit my code in order to get the extension view to animate up/down with a fade in/fade out effect?
Instead of calling self.view.layoutIfNeeded() in the completion block, try calling it inside the animation block on the last line before it returns.
I am animating a view by:
#IBAction func showInfo(sender: AnyObject) {
UIView.animateWithDuration(1,
delay: 0,
usingSpringWithDamping: 0.7,
initialSpringVelocity: 0.5,
options: nil,
animations: {
self.infoContainer.frame.origin.y = CGFloat(30)
}, completion: nil
)
}
My question now is if I need to run layoutIfNeeded() afterwards?
You need to call layoutIfNeeded() when you change constraints. You don't need to call it when animating by origin
Since you are animating by setting a new frame, you don't need to call layoutIfNeeded().
My guess is that you asked this question because it's not working for you. If you setup the view with AutoLayout, and try to modify the frame directly, it won't work, you have to animate by modifying the constants in the constraints.