Animate Auto Layout Constraints and Alpha on NSView
nsview, nsviewanimation
Solution
The modification of `alphaValue` is happening before you have turned on implicit animation, so the alpha will not be animated. It's unclear to me whether that was intentional or not.
The view is not animating to the position given by the `popupConstraint`s, because you're not actually doing anything inside the animation block that would cause the view's frame to change. In order to trigger an implicit animation, you must not only update constraints; you must also ensure that the view's `frame` changes within the animation block. If you're using AutoLayout, this is usually done by calling `layoutSubtreeIfNeeded`.
However, because you updated the constraints and called `layoutSubtreeIfNeeded()` prior to the animation block, there are no additional frame changes left to make inside the block (unless there's something happening down in `updateConstraints()` which you haven't shown us.)
You should remove the first call to `layoutSubtreeIfNeeded()`, or if it's still necessary, put it above the `popupConstraint` modifications. Then, when you call `layoutSubtreeIfNeeded()` within the animation block, a new frame will be set based on those changed constraints, and you should see animation happening.
Problem
Swift 3, iOS 10, macOS 10.12.4 I am building an app that runs on both iOS and Mac. On the iOS side, I have successfully animated a `UIView`. When the user taps on something, a popup appears and animates into position. Here's my code inside the tap event: ``` self.popupConstraintX.constant = x self.popupConstraintY.constant = y UIView.animate(withDuration: 0.25 , delay: 0.0, options: .curveLinear, animations: { self.graphPopup.alpha = 1.0 self.layoutIfNeeded() }, completion:nil) ``` In this case, `self` refers to a `UITableViewCell` that holds the `graphPopup`. I have built the same thing on the Mac side, but I'm trying to animate `graphPopup` which is now an `NSView`. Here's what I have so far inside my click event: ``` self.popupConstraintX.constant = x self.popupConstraintY.constant = y self.view.layoutSubtreeIfNeeded() NSAnimationContext.runAnimationGroup({_ in self.graphPopup.alphaValue = 1.0 //Indicate the duration of the animation NSAnimationContext.current().duration = 0.25 NSAnimationContext.current().allowsImplicitAnimation = true self.view.updateConstraints() self.view.layoutSubtreeIfNeeded() }, completionHandler:nil) ``` Here `self` refers to the containing `NSViewController`. Nothing animates--not the position or the `alpha` of `graphPopup`. It just appears and disappears like it's on an Atari in 1985. Any idea what I'm doing wrong with my `NSView` animation? Update For posterity's sake, here is the working code as suggested by BJ (with a slight tweak to use the implicit animation context): ``` self.popupConstraintX.constant = x self.popupConstraintY.constant = y NSAnimationContext.runAnimationGroup({context in context.duration = 0.25 context.allowsImplicitAnimation = true self.graphPopup.alphaValue = 1.0 self.view.layoutSubtreeIfNeeded() }, completionHandler:nil) ```