在UILabel中更改文字变化

我正在给UILabel设置一个新的文本值。 目前，新的文字显得很好。 不过，我想在出现新文字时添加一些animation。 我想知道我能做些什么来animation新文本的外观。

Answer 1

Objective-C的

为了实现真正的交叉转换（旧标签淡出而新标签淡入），您不希望淡入淡出。 即使文本不变，这也会导致不必要的闪烁 。

改用这种方法：

 CATransition *animation = [CATransition animation]; animation.timingFunction = [CAMediaTimingFunction functionWithName:kCAMediaTimingFunctionEaseInEaseOut]; animation.type = kCATransitionFade; animation.duration = 0.75; [aLabel.layer addAnimation:animation forKey:@"kCATransitionFade"]; // This will fade: aLabel.text = "New" 

另请参阅： 两个数字之间的animationUILabel文本？

iOS 10，9，8演示：

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使用Xcode 8.2.1和7.1 ， iOS 10到8.0的 ObjectiveC进行testing。

►要下载完整的项目， 请在Swift Recipes中searchSO-3073520 。

Answer 2

我不知道它是否工作，它完美的作品！

Objective-C的

 [UIView transitionWithView:self.label duration:0.25f options:UIViewAnimationOptionTransitionCrossDissolve animations:^{ self.label.text = rand() % 2 ? @"Nice nice!" : @"Well done!"; } completion:nil]; 

Swift 3

 UIView.transition(with: label, duration: 0.25, options: .transitionCrossDissolve, animations: { [weak self] in self?.label.text = (rand() % 2 == 0) ? "One" : "Two" }, completion: nil) 

Answer 3

Swift 3

淡入淡出UILabel（或任何UIView）的正确方法是使用Core Animation Transition 。 这不会闪烁，如果内容没有改变，也不会变黑。

一个可移植和干净的解决scheme是在Swift中使用Extension （在更改可见元素之前调用）

 // Usage: insert view.fadeTransition right before changing content extension UIView { func fadeTransition(_ duration:CFTimeInterval) { let animation = CATransition() animation.timingFunction = CAMediaTimingFunction(name: kCAMediaTimingFunctionEaseInEaseOut) animation.type = kCATransitionFade animation.duration = duration layer.add(animation, forKey: kCATransitionFade) } } 

调用如下所示：

 // This will fade aLabel.fadeTransition(duration: 0.4) aLabel.text = "text" 

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►在GitHub上find这个解决scheme和Swift Recipes的更多细节。

Answer 4

自iOS4以来，它可以显然完成块：

 [UIView animateWithDuration:1.0 animations:^{ label.alpha = 0.0f; label.text = newText; label.alpha = 1.0f; }]; 

Answer 5

这是做这个工作的代码。

 [UIView beginAnimations:@"animateText" context:nil]; [UIView setAnimationCurve:UIViewAnimationCurveEaseIn]; [UIView setAnimationDuration:1.0f]; [self.lbl setAlpha:0]; [self.lbl setText:@"New Text"; [self.lbl setAlpha:1]; [UIView commitAnimations]; 

Answer 6

Swift 2.0：

 UIView.transitionWithView(self.view, duration: 1.0, options: UIViewAnimationOptions.TransitionCrossDissolve, animations: { self.sampleLabel.text = "Animation Fade1" }, completion: { (finished: Bool) -> () in self.sampleLabel.text = "Animation Fade - 34" }) 

要么

 UIView.animateWithDuration(0.2, animations: { self.sampleLabel.alpha = 1 }, completion: { (value: Bool) in self.sampleLabel.alpha = 0.2 }) 

Answer 7

这是一个基于@ SwiftArchitect代码的C＃UIView扩展方法。 当涉及到自动布局并且控件需要根据标签的文本移动时，这个调用代码使用标签的超视图作为转换视图而不是标签本身。 我添加了一个lambdaexpression式来使其更加封装。

 public static void FadeTransition( this UIView AView, double ADuration, Action AAction ) { CATransition transition = new CATransition(); transition.Duration = ADuration; transition.TimingFunction = CAMediaTimingFunction.FromName( CAMediaTimingFunction.Linear ); transition.Type = CATransition.TransitionFade; AView.Layer.AddAnimation( transition, transition.Type ); AAction(); } 

调用代码：

  labelSuperview.FadeTransition( 0.5d, () => { if ( condition ) label.Text = "Value 1"; else label.Text = "Value 2"; } ); 

Answer 8

如果你想在Swift做这个，试试这个：

 delay(1.0) { UIView.transitionWithView(self.introLabel, duration: 0.25, options: [.TransitionCrossDissolve], animations: { self.yourLabel.text = "2" }, completion: { finished in self.delay(1.0) { UIView.transitionWithView(self.introLabel, duration: 0.25, options: [.TransitionCrossDissolve], animations: { self.yourLabel.text = "1" }, completion: { finished in }) } }) } 

使用@matt创build的以下函数 – https://stackoverflow.com/a/24318861/1982051 ：

 func delay(delay:Double, closure:()->()) { dispatch_after( dispatch_time( DISPATCH_TIME_NOW, Int64(delay * Double(NSEC_PER_SEC)) ), dispatch_get_main_queue(), closure) } 

这将在Swift 3中成为这个

 func delay(_ delay:Double, closure:()->()) { let when = DispatchTime.now() + delay DispatchQueue.main.after(when: when, execute: closure) } 

Answer 9

根据你的口味和需求，你可以select以下三个代码片段中的一个来为你的UILabel的文本更改添加一些交叉消解animation：

1.使用transition(with:duration:options:animations:completion:)

 import UIKit import PlaygroundSupport class ViewController: UIViewController { let label: UILabel = { $0.frame.origin = CGPoint(x: 50, y: 50) $0.text = "Bob" $0.sizeToFit() return $0 }(UILabel()) override func viewDidLoad() { super.viewDidLoad() view.backgroundColor = .white view.addSubview(label) let tapGesture = UITapGestureRecognizer(target: self, action: #selector(toggle(_:))) view.addGestureRecognizer(tapGesture) } func toggle(_ sender: UITapGestureRecognizer) { let animation = { self.label.text = self.label.text == "Bob" ? "Dan" : "Bob" } UIView.transition(with: label, duration: 1, options: .transitionCrossDissolve, animations: animation, completion: nil) } } let controller = ViewController() PlaygroundPage.current.liveView = controller 

2.使用CATransition和CATransition的type属性

 import UIKit import PlaygroundSupport class ViewController: UIViewController { let label: UILabel = { $0.frame.origin = CGPoint(x: 50, y: 50) $0.text = "Bob" $0.sizeToFit() return $0 }(UILabel()) let animation: CATransition = { $0.timingFunction = CAMediaTimingFunction(name: kCAMediaTimingFunctionEaseInEaseOut) $0.type = kCATransitionFade $0.duration = 1 return $0 }(CATransition()) override func viewDidLoad() { super.viewDidLoad() view.backgroundColor = .white view.addSubview(label) let tapGesture = UITapGestureRecognizer(target: self, action: #selector(toggle(_:))) view.addGestureRecognizer(tapGesture) } func toggle(_ sender: UITapGestureRecognizer) { label.layer.add(animation, forKey: nil) label.text = label.text == "Bob" ? "Dan" : "Bob" label.sizeToFit() } } let controller = ViewController() PlaygroundPage.current.liveView = controller 

3.使用CATransition并add(_:forKey:) key参数

 import UIKit import PlaygroundSupport class ViewController: UIViewController { let label: UILabel = { $0.frame.origin = CGPoint(x: 50, y: 50) $0.text = "Bob" $0.sizeToFit() return $0 }(UILabel()) let animation: CATransition = { $0.timingFunction = CAMediaTimingFunction(name: kCAMediaTimingFunctionEaseInEaseOut) $0.duration = 1 return $0 }(CATransition()) override func viewDidLoad() { super.viewDidLoad() view.backgroundColor = .white view.addSubview(label) let tapGesture = UITapGestureRecognizer(target: self, action: #selector(toggle(_:))) view.addGestureRecognizer(tapGesture) } func toggle(_ sender: UITapGestureRecognizer) { label.layer.add(animation, forKey: kCATransitionFade) label.text = label.text == "Bob" ? "Dan" : "Bob" label.sizeToFit() } } let controller = ViewController() PlaygroundPage.current.liveView = controller