NSView Animation not animating

Question

I'm trying to animate an NSView by changing the value of its leading constraint.

This is my constraint object:

@IBOutlet weak var vModDatesLeading: NSLayoutConstraint!

and the code I am using to animate its position:

@IBAction func getModDates(_ sender: Any) {
    
    NSAnimationContext.runAnimationGroup({ context in

        //Indicate the duration of the animation
        context.duration = 0.5
        vModDatesLeading.constant = 0
        vModDatesLeading.animator()
        vModDatesWrapper.layoutSubtreeIfNeeded()
       
       }, completionHandler:nil)
}

It is moving, but jumping, not animating. If this was iOS I would add:

view.layoutIfNeeded()

but that is not an option for NSView. I tried layoutSubtreeIfNeeded() but that did nada.

Any help would be appreciated.

Does this answer your question? [Animate Auto Layout Constraints and Alpha on NSView](https://stackoverflow.com/questions/43903105/animate-auto-layout-constraints-and-alpha-on-nsview) — Willeke, Apr 08 '21 at 06:01

Duncan C · Accepted Answer · 2021-04-08T15:41:08.760

1

I mostly work in iOS these days, and don't think I've ever used NSAnimationContext. I did a little digging, and it looks like you need to add the line

context.current.allowsImplicitAnimation = true

inside the body of your runAnimationGroup closure.

Edit:

I just noticed the line

vModDatesLeading.animator()

In your code. That doesn't do anything. The idea is that you should fetch an animator proxy for the object you are animating and apply your changes to that proxy. Thus your code should read:

NSAnimationContext.runAnimationGroup({ context in

    //Indicate the duration of the animation
    context.duration = 0.5
    vModDatesLeading.animator().constant = 0
    vModDatesWrapper.layoutSubtreeIfNeeded()
}

(Note that I haven't tested this. I think that would work without needing the context.current.allowsImplicitAnimation = true, but I'd have to test it to be sure.)

edited Apr 08 '21 at 15:41

answered Apr 07 '21 at 15:34

Duncan C

128,072
22
173
272

Is `NSAnimationContext.current` the same context as `context`? – Willeke Apr 08 '21 at 05:58
Yes. Sorry, I was working with a slightly different example where `context` wasn't defined. I'll edit my answer. – Duncan C Apr 08 '21 at 12:24
Either `context` or `NSAnimationContext.current` should work. – Duncan C Apr 08 '21 at 12:24
Just wanted to let you know I've seen this but haven't had a chance to test it yet. – PruitIgoe Apr 08 '21 at 14:24
Do you need `vModDatesWrapper.layoutSubtreeIfNeeded()`? Or is the answer the same as [Animate Auto Layout Constraints and Alpha on NSView](https://stackoverflow.com/a/62954619)? – Willeke Apr 08 '21 at 21:57
That was it. Thanks! – PruitIgoe Apr 13 '21 at 19:20

NSView Animation not animating

1 Answers1

Edit: