UIView.animateWithDuration 不动画 Swift（再次）

Question

Note: I've already checked the following stack overflow issues:

27907570 , 32229252 , 26118141 , 31604300

All I am trying to do is fade animate in a view (by alpha) when called by an IBAction attached to a button. Then reverse when a button on the view is hit.

My wrinkle may be that I'm using a secondary view that is on the ViewDock in the storyboard View. The view is added to the subview at the time of viewDidLoad where the frame/bounds are set to the same as the superview (for a full layover)

The reason this is done as an overlay view since it is a tutorial indicator.

The result (like many others who've listed this problem) is that the view (and contained controls) simply appears instantly and disappears as instantly. No fade.

I have tried animationWithDuration with delay, with and without completion, with transition, and even started with the old UIView.beginAnimations.

Nothing is working. Suggestions warmly welcomed.

The code is about as straight forward as I can make it:
Edit: Expanded the code to everything relevant
Edit2: TL;DR Everything works with the exception of UIViewAnimateWithDuration which seems to ignore the block and duration and just run the code inline as an immediate UI change. Solving this gets the bounty

@IBOutlet var infoDetailView: UIView! // Connected to the view in the SceneDock

override func viewDidLoad() {
    super.viewDidLoad()

    // Cut other vDL code that isn't relevant

    setupInfoView()
}

func setupInfoView() {
    infoDetailView.alpha = 0.0
    view.addSubview(infoDetailView)
    updateInfoViewRect(infoDetailView.superview!.bounds.size)
}

func updateInfoViewRect(size:CGSize) {
    let viewRect = CGRect(origin: CGPointZero, size: size)

    infoDetailView.frame = viewRect
    infoDetailView.bounds = viewRect

    infoDetailView.layoutIfNeeded()
    infoDetailView.setNeedsDisplay()
}

override func viewWillTransitionToSize(size: CGSize, withTransitionCoordinator coordinator: UIViewControllerTransitionCoordinator) {
    super.viewWillTransitionToSize(size, withTransitionCoordinator: coordinator)
    updateInfoViewRect(size)
}

func hideInfoView() {
    AFLog.enter(thisClass)
    UIView.animateWithDuration(
        2.0,
        animations:
        {
            self.infoDetailView.alpha = 0.0
        },
        completion:
        { (finished) in
            return true
        }
    )
    AFLog.exit(thisClass)
}

func showInfoView() {
    AFLog.enter(thisClass)
    UIView.animateWithDuration(
        2.0,
        animations:
        {
            self.infoDetailView.alpha = 0.75
        },
        completion:
        { (finished) in
            return true
        }
    )
    AFLog.exit(thisClass)
}

// MARK: - IBActions

@IBAction func openInfoView(sender: UIButton) {
    showInfoView()
}

@IBAction func closeInfoView(sender: UIButton) {
    hideInfoView()
}

Please note, I started with the following:

func showInfoView() {
    UIView.animateWithDuration(2.0, animations: { () -> Void in
        self.infoDetailView.alpha = 0.75
    })
}

func hideInfoView() {
    UIView.animateWithDuration(2.0, animations: { () -> Void in
        self.infoDetailView.alpha = 0.00
    })
}

Answer 1

If you infoDetailView is under auto layout constraints you need to call layoutIfNeeded on the parent view inside animateWithDuration:

func showInfoView() {
    self.view.layoutIfNeeded() // call it also here to finish pending layout operations
    UIView.animate(withDuration: 2.0, animations: {
        self.infoDetailView.alpha = 0.75
        self.view.layoutIfNeeded()
    })
}

Theoretically this should not be needed if you just change the .alpha value, but maybe this could be the problem in this case.

Answer 2

There are several strange things I can see,

first, remove:

infoDetailView.layoutIfNeeded()
infoDetailView.setNeedsDisplay()

Usually you don't need to call those methods manually unless you know exactly what you are doing.

Also, when you are changing the size:

infoDetailView.frame = viewRect
infoDetailView.bounds = viewRect

You never need to set both bounds and frame . Just set frame .

Also, you should probably make sure that the view actually doesn't ignore the frame by setting:

infoDetailView.translatesAutoresizingMaskIntoConstraints = true

Instead of resetting the frame, just set autoresize mask:

infoDetailView.autoresizingMask = [.FlexibleWidth, .FlexibleHeight]

Resulting in:

override func viewDidLoad() {
    super.viewDidLoad()

    // Cut other vDL code that isn't relevant

    setupInfoView()
}

func setupInfoView() {
    infoDetailView.alpha = 0.0
    infoDetailView.translatesAutoresizingMaskIntoConstraints = true
    infoDetailView.autoresizingMask = [.FlexibleWidth, .FlexibleHeight]
    infoDetailView.frame = view.bounds
    view.addSubview(infoDetailView)
}

func hideInfoView() {
  ...
}

I think this should actually help because immediate animations are often connected to size problems.

If the problem persists, you should check whether the infoDetailView in your animation is the same object as the infoDetailView you are adding to the controller.

Answer 3

For others looking to start an animation immediately when a view loads...

The animation won't work if you call UIView.animate(...) inside viewDidLoad . Instead it must be called from the viewDidAppear function.

override func viewDidAppear(_ animated: Bool) {
    UIView.animate(withDuration: 3) {
        self.otherView.frame.origin.x += 500
    }
}

Answer 4

If the animation does not seem to execute then consider examining the state of each of your views, before you enter the animation block. For example, if the alpha is already set to 0.4 then the animation that adjusts your view alpha, will complete almost instantly, with no apparent effect.

Consider using a keyframe animation instead. This is what a shake animation in objective c looks like.

+(CAKeyframeAnimation*)shakeAnimation {
    CAKeyframeAnimation *animation = [CAKeyframeAnimation animationWithKeyPath:@"transform"];
    animation.values = @[[NSValue valueWithCATransform3D:CATransform3DMakeTranslation(-10.0, 0.0, 0.0)],
                         [NSValue valueWithCATransform3D:CATransform3DMakeTranslation(10.0, 0.0, 0.0)]];
    animation.autoreverses = YES;
    animation.repeatCount = 2;
    animation.duration = 0.07;
    return animation;
}

Here is a post that shows you how to adjust alpha with keyframes https://stackoverflow.com/a/18658081/1951992

Answer 5

Make sure infoDetailView 's opaque is false.

https://developer.apple.com/library/ios/documentation/UIKit/Reference/UIView_Class/#//apple_ref/occ/instp/UIView/opaque

This property provides a hint to the drawing system as to how it should treat the view. If set to true, the drawing system treats the view as fully opaque, which allows the drawing system to optimize some drawing operations and improve performance. If set to false, the drawing system composites the view normally with other content. The default value of this property is true.

Answer 6

Use this code:

Swift 2

UIView.animateWithDuration(0.3, animations: { () -> Void in
    self.infoDetailView.alpha = 0.0 
})

Swift 3, 4, 5

UIView.animate(withDuration: 0.3, animations: { () -> Void in
    self.infoDetailView.alpha = 0.0 
})

Answer 7

I've replicated your code and it work well, it's all ok. Probably you must control constraints, IBOutlet and IBActions connections. Try to isolate this code into a new project if it's necessary.

Update : my code and my storyboard and project folder photo:

Every object (view and buttons) are with default settings.

I've commented all AFLog lines (probably it's only any more "verbose mode" to help you) , the rest of your code is ok and it do what do you aspected from it, if you press open button the view fade in, and when you tap close button the view fade out.

PS Not relevant but i'm using xCode 7.3 , a new swift 2.2 project.

Answer 8

Try Below code. Just play with alpha and duration time to perfect it.

Hide func

func hideInfoView() {
AFLog.enter(thisClass)
UIView.animateWithDuration(
    2.0,
    animations:
    {
        self.infoDetailView.alpha = 0.8
    },
    completion:
    { (finished) in
        UIView.animateWithDuration(
    2.0,
    animations:
    {
        self.infoDetailView.alpha = 0.4
    },
    completion:
    { (finished) in
        self.infoDetailView.alpha = 0.0
    }
)
    }
)
AFLog.exit(thisClass)
}

Show func

func showInfoView() {
AFLog.enter(thisClass)
UIView.animateWithDuration(
    2.0,
    animations:
    {
        self.infoDetailView.alpha = 0.3
    },
    completion:
    { (finished) in
        UIView.animateWithDuration(
    2.0,
    animations:
    {
        self.infoDetailView.alpha = 0.7
    },
    completion:
    { (finished) in
        self.infoDetailView.alpha = 1.0
    }
)
    }
)
AFLog.exit(thisClass)
}

Answer 9

Have you tried changing your showInfoView() to something more like toggleInfoView ?

func toggleInfoView() {
    let alpha = CGFloat(infoDetailView.alpha == 0 ? 1 : 0)
    infoDetailView.alpha = alpha       //this is where the toggle happens
}

It says that if your view's alpha is 0, then change it to 1. Else, make it 0.

If you need that to happen in an animation, try

@IBAction func openInfoView(sender: UIButton) {
    UIView.animate(withDuration: 2.0, animations: {
        self.toggleInfoView()           //fade in/out infoDetailView when animating
    })   
}

• You'll still want to keep that infoDetailView.alpha = 0.0 where you have it, coming from the viewDidLoad .

Answer 10

For UILabel component try to changes layer's background color instead.

Try this (Tested on Swift 4):

UIView.animate(withDuration: 0.2, animations: { 
    self.dateLabel.layer.backgroundColor = UIColor.red.cgColor;
})

Answer 11

Had a similar issue with animation not being performed.

Changed the function call use perform(aSelector: Selector, with: Any?, afterDelay: TimeInterval) in the form of perform(#selector(functionThatDoesAnimationOfAlphaValue), with: nil, afterDelay: 0) and it worked. Even with a TimeInterval set to 0.

In case someone else comes here wondering for a solution.