UIView Hide/Show with animation

Question

My simple goal is to fade animate hiding and showing functions.

Button.hidden = YES;

Simple enough. However, is it possible to have it fade out rather than just disappearing? It looks rather unprofessional that way.

Answer 1

In iOS 4 and later, there's a way to do this just using the UIView transition method without needing to import QuartzCore. You can just say:

[UIView transitionWithView:button
                  duration:0.4
                   options:UIViewAnimationOptionTransitionCrossDissolve
                animations:^{
                     button.hidden = YES;
                }
                completion:NULL];

Previous Solution

Michail's solution will work, but it's not actually the best approach.

The problem with alpha fading is that sometimes the different overlapping view layers look weird as they fade out. There are some other alternatives using Core Animation. First include the QuartzCore framework in your app and add #import <QuartzCore/QuartzCore.h> to your header. Now you can do one of the following:

1) set button.layer.shouldRasterize = YES; and then use the alpha animation code that Michail provided in his answer. This will prevent the layers from blending weirdly, but has a slight performance penalty, and can make the button look blurry if it's not aligned exactly on a pixel boundary.

Alternatively:

2) Use the following code to animate the fade instead:

CATransition *animation = [CATransition animation];
animation.type = kCATransitionFade;
animation.duration = 0.4;
[button.layer addAnimation:animation forKey:nil];

button.hidden = YES;

The nice thing about this approach is you can crossfade any property of the button even if they aren't animatable (e.g. the text or image of the button), just set up the transition and then set your properties immediately afterwards.

Answer 2

UIView animated properties are:

- frame
- bounds
- center
- transform
- alpha
- backgroundColor
- contentStretch

Describe in: Animations

isHidden is not one of them, so as I see it the best way is:

Swift 4:

func setView(view: UIView, hidden: Bool) {
    UIView.transition(with: view, duration: 0.5, options: .transitionCrossDissolve, animations: {
        view.isHidden = hidden
    })
}

Objective C:

- (void)setView:(UIView*)view hidden:(BOOL)hidden {
    [UIView transitionWithView:view duration:0.5 options:UIViewAnimationOptionTransitionCrossDissolve animations:^(void){
        [view setHidden:hidden];
    } completion:nil];
}

Answer 3

To fade out:

[UIView animateWithDuration:0.3 animations:^{
    button.alpha = 0;
} completion: ^(BOOL finished) {//creates a variable (BOOL) called "finished" that is set to *YES* when animation IS completed.
    button.hidden = finished;//if animation is finished ("finished" == *YES*), then hidden = "finished" ... (aka hidden = *YES*)
}];

// swift:
UIView.animateWithDuration(0.3, animations: {
    button.alpha = 0
}) { (finished) in
    button.hidden = finished
}

To fade in:

button.alpha = 0;
button.hidden = NO;
[UIView animateWithDuration:0.3 animations:^{
    button.alpha = 1;
}];

// swift:
button.alpha = 0
button.hidden = false
UIView.animateWithDuration(0.3) {
    button.alpha = 1
}

Answer 4

I use this little Swift 3 extension:

extension UIView {

  func fadeIn(duration: TimeInterval = 0.5,
              delay: TimeInterval = 0.0,
              completion: @escaping ((Bool) -> Void) = {(finished: Bool) -> Void in }) {
    UIView.animate(withDuration: duration,
                   delay: delay,
                   options: UIViewAnimationOptions.curveEaseIn,
                   animations: {
      self.alpha = 1.0
    }, completion: completion)
  }

  func fadeOut(duration: TimeInterval = 0.5,
               delay: TimeInterval = 0.0,
               completion: @escaping (Bool) -> Void = {(finished: Bool) -> Void in }) {
    UIView.animate(withDuration: duration,
                   delay: delay,
                   options: UIViewAnimationOptions.curveEaseIn,
                   animations: {
      self.alpha = 0.0
    }, completion: completion)
  }
}

Answer 5

Swift 3

func appearView() {
     self.myView.alpha = 0
     self.myView.isHidden = false

     UIView.animate(withDuration: 0.9, animations: {
         self.myView.alpha = 1
     }, completion: {
         finished in
         self.myView.isHidden = false
     })
}

Answer 6

I created category for UIView for this purpose and implemented a special little bit different concept: visibility. The main difference of my solution is that you can call [view setVisible:NO animated:YES] and right after that synchronously check [view visible] and get correct result. This is pretty simple but extremely useful.

Besides, it is allowed to avoid using "negative boolean logic" (see Code Complete, page 269, Use positive boolean variable names for more information).

Swift

UIView+Visibility.swift

import UIKit


private let UIViewVisibilityShowAnimationKey = "UIViewVisibilityShowAnimationKey"
private let UIViewVisibilityHideAnimationKey = "UIViewVisibilityHideAnimationKey"


private class UIViewAnimationDelegate: NSObject {
    weak var view: UIView?

    dynamic override func animationDidStop(animation: CAAnimation, finished: Bool) {
        guard let view = self.view where finished else {
            return
        }

        view.hidden = !view.visible
        view.removeVisibilityAnimations()
    }
}


extension UIView {

    private func removeVisibilityAnimations() {
        self.layer.removeAnimationForKey(UIViewVisibilityShowAnimationKey)
        self.layer.removeAnimationForKey(UIViewVisibilityHideAnimationKey)
    }

    var visible: Bool {
        get {
            return !self.hidden && self.layer.animationForKey(UIViewVisibilityHideAnimationKey) == nil
        }

        set {
            let visible = newValue

            guard self.visible != visible else {
                return
            }

            let animated = UIView.areAnimationsEnabled()

            self.removeVisibilityAnimations()

            guard animated else {
                self.hidden = !visible
                return
            }

            self.hidden = false

            let delegate = UIViewAnimationDelegate()
            delegate.view = self

            let animation = CABasicAnimation(keyPath: "opacity")
            animation.fromValue = visible ? 0.0 : 1.0
            animation.toValue = visible ? 1.0 : 0.0
            animation.fillMode = kCAFillModeForwards
            animation.removedOnCompletion = false
            animation.delegate = delegate

            self.layer.addAnimation(animation, forKey: visible ? UIViewVisibilityShowAnimationKey : UIViewVisibilityHideAnimationKey)
        }
    }

    func setVisible(visible: Bool, animated: Bool) {
        let wereAnimationsEnabled = UIView.areAnimationsEnabled()

        if wereAnimationsEnabled != animated {
            UIView.setAnimationsEnabled(animated)
            defer { UIView.setAnimationsEnabled(!animated) }
        }

        self.visible = visible
    }

}

Objective-C

UIView+Visibility.h

#import <UIKit/UIKit.h>

@interface UIView (Visibility)

- (BOOL)visible;
- (void)setVisible:(BOOL)visible;
- (void)setVisible:(BOOL)visible animated:(BOOL)animated;

@end

UIView+Visibility.m

#import "UIView+Visibility.h"

NSString *const UIViewVisibilityAnimationKeyShow = @"UIViewVisibilityAnimationKeyShow";
NSString *const UIViewVisibilityAnimationKeyHide = @"UIViewVisibilityAnimationKeyHide";

@implementation UIView (Visibility)

- (BOOL)visible
{
    if (self.hidden || [self.layer animationForKey:UIViewVisibilityAnimationKeyHide]) {
        return NO;
    }

    return YES;
}

- (void)setVisible:(BOOL)visible
{
    [self setVisible:visible animated:NO];
}

- (void)setVisible:(BOOL)visible animated:(BOOL)animated
{
    if (self.visible == visible) {
        return;
    }

    [self.layer removeAnimationForKey:UIViewVisibilityAnimationKeyShow];
    [self.layer removeAnimationForKey:UIViewVisibilityAnimationKeyHide];

    if (!animated) {
        self.alpha = 1.f;
        self.hidden = !visible;
        return;
    }

    self.hidden = NO;

    CGFloat fromAlpha = visible ? 0.f : 1.f;
    CGFloat toAlpha = visible ? 1.f : 0.f;
    NSString *animationKey = visible ? UIViewVisibilityAnimationKeyShow : UIViewVisibilityAnimationKeyHide;

    CABasicAnimation *animation = [CABasicAnimation animationWithKeyPath:@"opacity"];
    animation.duration = 0.25;
    animation.fromValue = @(fromAlpha);
    animation.toValue = @(toAlpha);
    animation.delegate = self;
    animation.removedOnCompletion = NO;
    animation.fillMode = kCAFillModeForwards;
    [self.layer addAnimation:animation forKey:animationKey];
}

#pragma mark - CAAnimationDelegate

- (void)animationDidStop:(CAAnimation *)animation finished:(BOOL)finished
{
    if ([[self.layer animationForKey:UIViewVisibilityAnimationKeyHide] isEqual:animation]) {
        self.hidden = YES;
    }
}

@end

Answer 7

Swift 4

extension UIView {

func fadeIn(duration: TimeInterval = 0.5, delay: TimeInterval = 0.0, completion: @escaping ((Bool) -> Void) = {(finished: Bool) -> Void in }) {
    self.alpha = 0.0

    UIView.animate(withDuration: duration, delay: delay, options: UIViewAnimationOptions.curveEaseIn, animations: {
        self.isHidden = false
        self.alpha = 1.0
    }, completion: completion)
}

func fadeOut(duration: TimeInterval = 0.5, delay: TimeInterval = 0.0, completion: @escaping (Bool) -> Void = {(finished: Bool) -> Void in }) {
    self.alpha = 1.0

    UIView.animate(withDuration: duration, delay: delay, options: UIViewAnimationOptions.curveEaseIn, animations: {
        self.alpha = 0.0
    }) { (completed) in
        self.isHidden = true
        completion(true)
    }
}
}

And to use use it, simple call these functions like:

yourView.fadeOut() // this will hide your view with animation
yourView.fadeIn() /// this will show your view with animation

Answer 8

the code of @Umair Afzal working fine in swift 5 after some changes

 extension UIView {

func fadeIn(duration: TimeInterval = 0.5, delay: TimeInterval = 0.0, completion: @escaping ((Bool) -> Void) = {(finished: Bool) -> Void in }) {
    self.alpha = 0.0

    UIView.animate(withDuration: duration, delay: delay, options: UIView.AnimationOptions.curveEaseIn, animations: {
        self.isHidden = false
        self.alpha = 1.0
    }, completion: completion)
}

func fadeOut(duration: TimeInterval = 0.5, delay: TimeInterval = 0.0, completion: @escaping (Bool) -> Void = {(finished: Bool) -> Void in }) {
    self.alpha = 1.0

    UIView.animate(withDuration: duration, delay: delay, options: UIView.AnimationOptions.curveEaseIn, animations: {
        self.alpha = 0.0
    }) { (completed) in
        self.isHidden = true
        completion(true)
    }
  }
}

for use

yourView.fadeOut()
yourView.fadeIn()

Answer 9

swift 4.2

with extension :

extension UIView {
func hideWithAnimation(hidden: Bool) {
        UIView.transition(with: self, duration: 0.5, options: .transitionCrossDissolve, animations: {
            self.isHidden = hidden
        })
    }
}

simple method:

func setView(view: UIView, hidden: Bool) {
    UIView.transition(with: view, duration: 0.5, options: .transitionCrossDissolve, animations: {
        view.isHidden = hidden
    })
}

Answer 10

You can do it VERY easily using Animatics library:

//To hide button:
AlphaAnimator(0) ~> button

//to show button
AlphaAnimator(1) ~> button

Answer 11

func flipViews(fromView: UIView, toView: UIView) {

    toView.frame.origin.y = 0

    self.view.isUserInteractionEnabled = false

    UIView.transition(from: fromView, to: toView, duration: 0.5, options: .transitionFlipFromLeft, completion: { finished in            

        fromView.frame.origin.y = -900

        self.view.isUserInteractionEnabled = true

    })


}

Answer 12

You can try this.

 func showView(objView:UIView){

    objView.alpha = 0.0
    UIView.animate(withDuration: 0.5, animations: {
        objView.alpha = 0.0
    }, completion: { (completeFadein: Bool) -> Void in
        objView.alpha = 1.0
        let transition = CATransition()
        transition.duration = 0.5
        transition.timingFunction = CAMediaTimingFunction(name: kCAMediaTimingFunctionEaseInEaseOut)
        transition.type = kCATransitionFade
        objView.layer.add(transition, forKey: nil)
    })
}

func HideView(objView:UIView){

    UIView.animate(withDuration: 0.5, animations: {
        objView.alpha = 1.0
    }, completion: { (completeFadein: Bool) -> Void in
        objView.alpha = 0.0
        let transition = CATransition()
        transition.duration = 0.5
        transition.timingFunction = CAMediaTimingFunction(name: kCAMediaTimingFunctionEaseInEaseOut)
        transition.type = kCATransitionFade
        objView.layer.add(transition, forKey: nil)
    })
}

And pass your view name

        showView(objView: self.viewSaveCard)
        HideView(objView: self.viewSaveCard)

Answer 13

My solution for Swift 3. So, I created the function, that hide/unhide view in the right order(when hiding - set alpha to 0 and then isHidden to true; unhiding - first reveal the view and then set it's alpha to 1):

func hide(_ hide: Bool) {
    let animations = hide ? { self.alpha = 0 } :
                            { self.isHidden = false }
    let completion: (Bool) -> Void = hide ? { _ in self.isHidden = true } :
                                            { _ in UIView.animate(withDuration: duration, animations: { self.alpha = 1 }) }
    UIView.animate(withDuration: duration, animations: animations, completion: completion)
}

Answer 14

Swift 4 Transition

    UIView.transition(with: view, duration: 3, options: .transitionCurlDown,
                      animations: {
                        // Animations
                        view.isHidden = hidden
    },
                      completion: { finished in
                        // Compeleted
    })

If you use the approach for older swift versions you'll get an error :

Cannot convert value of type '(_) -> ()' to expected argument type '(() -> Void)?'

Useful reference.

Answer 15

This code give an animation like pushing viewController in uinavigation controller...

CATransition *animation = [CATransition animation];
 animation.type = kCATransitionPush;
 animation.subtype = kCATransitionFromRight;
 animation.duration = 0.3;
 [_viewAccountName.layer addAnimation:animation forKey:nil];

 _viewAccountName.hidden = true;

Used this for pop animation...

 CATransition *animation = [CATransition animation];
 animation.type = kCATransitionPush;
 animation.subtype = kCATransitionFromLeft;
 animation.duration = 0.3;
 [_viewAccountName.layer addAnimation:animation forKey:nil];

 _viewAccountName.hidden = false;

Answer 16

Tried some of the exited answers, some only work for one situation, some of them need to add two functions.

Option 1

Nothing to do with view.isHidden.

extension UIView {
    func animate(fadeIn: Bool, withDuration: TimeInterval = 1.0) {
        UIView.animate(withDuration: withDuration, delay: 0.0, options: .curveEaseInOut, animations: {
            self.alpha = fadeIn ? 1.0 : 0.0
        })
    }
}

Then pass isFadeIn (true or false)

view.animate(fadeIn: isFadeIn) 

Option 2

Don't pass any parameter. It fades in or out according to isUserInteractionEnabled. This also suits the situation animate back and forth very well.

func animateFadeInOut(withDuration: TimeInterval = 1.0) {
    self.isUserInteractionEnabled = !self.isUserInteractionEnabled
    UIView.animate(withDuration: withDuration, delay: 0.0, options: .curveEaseInOut, animations: {
        self.alpha = self.isUserInteractionEnabled ? 1.0 : 0.0
    })
}

Then you call

yourView.animateFadeInOut()

Why self.isUserInteractionEnabled ?

Tried to replace self.isUserInteractionEnabled by self.isHidden, no luck at all.

That's it. Cost me sometime, hope it helps someone.

Answer 17

Use this solution for a smooth fadeOut and fadeIn effects

extension UIView {
    func fadeIn(duration: TimeInterval = 0.5, delay: TimeInterval = 0.0, completion: @escaping ((Bool) -> Void) = {(finished: Bool) -> Void in }) {
        self.alpha = 0.0

        UIView.animate(withDuration: duration, delay: delay, options: UIView.AnimationOptions.curveEaseIn, animations: {
            self.isHidden = false
            self.alpha = 1.0
        }, completion: completion)
    }

    func fadeOut(duration: TimeInterval = 0.5, delay: TimeInterval = 0.0, completion: @escaping (Bool) -> Void = {(finished: Bool) -> Void in }) {
        self.alpha = 1.0

        UIView.animate(withDuration: duration, delay: delay, options: UIView.AnimationOptions.curveEaseOut, animations: {
            self.isHidden = true
            self.alpha = 0.0
        }, completion: completion)
    }
}

usage is as like

uielement.fadeIn()
uielement.fadeOut()

Thanks