UIView隐藏/显示动画

我的简单目标是淡化动画隐藏和显示功能。

Button.hidden = YES;

很简单。但是，有可能使它淡出而不是消失吗？这样看来相当不专业。

在iOS 4及更高版本中，有一种方法可以仅使用UIView过渡方法来执行此操作，而无需导入QuartzCore。您可以说：

目标C

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

迅速

UIView.transition(with: button, duration: 0.4, 
                  options: .transitionCrossDissolve, 
                  animations: {
                 button.hidden = false
              })

先前的解决方案

Michail的解决方案会起作用，但实际上并不是最佳方法。

Alpha淡入的问题在于，有时不同的重叠视图层在淡出时看起来很奇怪。还有一些使用Core Animation的替代方法。首先在您的应用程序中包含QuartzCore框架，并将其添加#import <QuartzCore/QuartzCore.h>到标题中。现在，您可以执行以下操作之一：

1）设置button.layer.shouldRasterize = YES;然后使用Michail在其答案中提供的alpha动画代码。这样可以防止各层怪异地融合在一起，但会降低性能，并且如果按钮未完全在像素边界上对齐，则可能会使按钮显得模糊。

或者：

2）改用以下代码设置淡入淡出的动画效果：

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

button.hidden = YES;

这种方法的好处是，即使按钮无法设置动画（例如按钮的文本或图像），您也可以对其进行淡入淡出处理，只需设置过渡，然后立即设置属性即可。

UIView动画属性是：

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

描述： 动画

isHidden 不是其中之一，因此我认为最好的方法是：

斯威夫特4：

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

目标C：

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

淡出：

目标C

[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*)
}];

迅捷2

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

斯威夫特3，4，5

UIView.animate(withDuration: 0.3, animations: {
    button.alpha = 0
}) { (finished) in
    button.isHidden = finished
}

淡入：

目标C

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

迅捷2

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

斯威夫特3，4，5

button.alpha = 0
button.isHidden = false
UIView.animate(withDuration: 0.3) {
    button.alpha = 1
}

我使用这个Swift 3扩展名：

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)
  }
}

迅捷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
     })
}

迅捷4.2

带有扩展名：

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

简单方法：

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

使用此解决方案可获得平滑的淡出和淡入效果

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)
    }
}

用法就像

uielement.fadeIn()
uielement.fadeOut()

谢谢

UIView为此，我创建了类别，并实现了一个特殊的概念：visibility。我的解决方案的主要区别在于，您可以在调用[view setVisible:NO animated:YES]后立即进行同步检查[view visible]并获得正确的结果。这很简单，但是非常有用。

此外，允许避免使用“负布尔逻辑”（有关更多信息，请参见 代码完成，第269页，使用正布尔变量名）。

迅速

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
    }

}

目标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

经过一些更改后，@ Umair Afzal的代码在swift 5中工作正常

 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)
    }
  }
}

用来

yourView.fadeOut()
yourView.fadeIn()

斯威夫特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)
    }
}
}

要使用它，只需调用以下函数即可：

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

isHidden 是一个立即值，您不能影响其上的动画，相反，您可以使用Alpha隐藏视图

UIView.transition(with: view, duration: 0.5, options: .transitionCrossDissolve, animations: {
        view.alpha = 0
    })

并显示：

UIView.transition(with: view, duration: 0.5, options: .transitionCrossDissolve, animations: {
      view.alpha = 1
})

您可以使用Animatics库轻松完成此操作：

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

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

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

    })


}

你可以试试看

 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)
    })
}

并传递您的视图名称

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

如果您的视图默认情况下设为“隐藏”，或者您更改了“隐藏”状态（我认为在很多情况下应该这样做），那么此页面中的任何一种方法都不会同时为您提供FadeIn / FadeOut动画，它只会为其中一种状态设置动画，原因是您在调用UIView.animate之前将Hidden状态设置为false方法这将导致突然的可见性；如果仅对Alpha进行动画处理，则对象空间仍然存在，但是不可见，这将导致某些UI问题。

因此，最好的方法是先检查视图是否被隐藏，然后将alpha设置为0.0，这样将Hidden状态设置为false时，您将不会看到可见的图像。

func hideViewWithFade(_ view: UIView) {
    if view.isHidden {
        view.alpha = 0.0
    }

    view.isHidden = false

    UIView.animate(withDuration: 0.3, delay: 0.0, options: .transitionCrossDissolve, animations: {
        view.alpha = view.alpha == 1.0 ? 0.0 : 1.0
    }, completion: { _ in
        view.isHidden = !Bool(truncating: view.alpha as NSNumber)
    })
}

UIView.transition（with :)函数非常简洁。

许多人都发布了它，但没有人注意到只有在运行它时才会出现故障。

您可以将隐藏属性完美地转换为true，而当您尝试将其转换为false时，视图将突然消失而没有任何动画。

这是因为此api仅在视图中起作用，这意味着当您转换视图以显示（实际上本身会立即显示）时，仅其内容会逐渐动画。

当您尝试隐藏此视图时，其本身会立即隐藏，从而使动画内容无意义。

为了解决这个问题，在隐藏视图时，过渡目标应该是其父视图，而不是要隐藏的视图。

func transitionView(_ view: UIView?, show: Bool, completion: BoolFunc? = nil) {
    guard let view = view, view.isHidden == show, let parent = view.superview else { return }

    let target: UIView = show ? view : parent
    UIView.transition(with: target, duration: 0.4, options: [.transitionCrossDissolve], animations: {
        view.isHidden = !show
    }, completion: completion)
}

我对Swift 3的解决方案。因此，我创建了一个函数，该函数以正确的顺序隐藏/取消隐藏视图（隐藏时-将alpha设置为0，然后将isHidden设置为true；取消隐藏-首先显示视图，然后将其alpha设置为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)
}

迅捷4过渡

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

如果您将方法用于较早的Swift版本，则会收到错误消息：

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

有用的参考。

这段代码给出了一个动画，就像在uinavigation controller中推送viewController一样。

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

 _viewAccountName.hidden = true;

用于流行动画...

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

 _viewAccountName.hidden = false;

尝试了一些已存在的答案，一些仅在一种情况下有效，其中一些需要添加两个功能。

选项1

与无关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
        })
    }
}

然后通过isFadeIn（true或false）

view.animate(fadeIn: isFadeIn) 

选项2

不要传递任何参数。根据淡入或淡出isUserInteractionEnabled。这也非常适合来回动画的情况。

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
    })
}

然后你打电话

yourView.animateFadeInOut()

为什么self.isUserInteractionEnabled呢

试图替换self.isUserInteractionEnabled为self.isHidden，根本没有运气。

而已。花了我一些时间，希望它能帮助别人。