在两个数字之间设置UILabel文本的动画？

Question

我是iPhone和Mac编程的新手(以前为Windows开发过),我有一个问题:

我如何动画text的属性UILabel两个数字之间,例如从5至80在渐出风格？有可能CoreAnimation吗？我一直在Google上搜索一个小时,但我找不到解决问题的方法.我想要的是:为一个简单的游戏动画用户的钱.当它从50到100或没有动画的那样时它看起来不太好.

任何人都知道如何做到这一点？

谢谢!

Answer 1

您可以使用自动转换.它工作得非常好:

// Add transition (must be called after myLabel has been displayed)
 CATransition *animation = [CATransition animation];
animation.duration = 1.0;
animation.type = kCATransitionFade;
animation.timingFunction = [CAMediaTimingFunction functionWithName:kCAMediaTimingFunctionEaseInEaseOut];
[myLabel.layer addAnimation:animation forKey:@"changeTextTransition"];

// Change the text
myLabel.text = newText;

如果已显示myLabel,则此代码有效.如果不是myLabel.layer将为nil并且动画将不会添加到对象中.

在Swift 4中将是:

let animation: CATransition = CATransition()
animation.duration = 1.0
animation.type = kCATransitionFade
animation.timingFunction = CAMediaTimingFunction(name: kCAMediaTimingFunctionEaseInEaseOut)
myLabel.layer.add(animation, forKey: "changeTextTransition")

Answer 2

它运作良好!

Objective-C的

[UIView transitionWithView:self.label 
                  duration:.5f 
                   options:UIViewAnimationOptionCurveEaseInOut | 
                           UIViewAnimationOptionTransitionCrossDissolve 
                animations:^{

    self.label.text = rand() % 2 ? @"111!" : @"42";

} completion:nil];

迅速

UIView.transitionWithView(label, duration: 0.25, options: [.CurveEaseInOut, .TransitionCrossDissolve], animations: {
    self.label.text = (arc4random() % 2 == 0) ? "111" : "222"
}, completion: nil)

Answer 3

我发现了一个很棒的引擎,用于使用称为PRTween的各种不同的计时函数来补间值.安装类并沿这些行创建一些代码:

- (IBAction)tweenValue
{
    [[PRTween sharedInstance] removeTweenOperation:activeTweenOperation];
    PRTweenPeriod *period = [PRTweenPeriod periodWithStartValue:0.0 endValue:100.0 duration:1.0];
    activeTweenOperation = [[PRTween sharedInstance] addTweenPeriod:period
                                                             target:self
                                                           selector:@selector(update:)
                                                     timingFunction:&PRTweenTimingFunctionCircOut];
}

- (void)update:(PRTweenPeriod*)period
{
    self.animatingView.center = CGPointMake(period.tweenedValue + 100.0, 200.0);
    self.valueLabel.text = [NSString stringWithFormat:@"%.2f", period.tweenedValue];
}

为我服务.:)

Answer 4

如果你想让它用新的数字向上和向下计数推动前一个数字(如股票代码或其他东西):

let animation = CATransition()
animation.removedOnCompletion = true
animation.duration = 0.2
animation.type = kCATransitionPush
animation.subtype = newValue > value ? kCATransitionFromTop : kCATransitionFromBottom
animation.timingFunction = CAMediaTimingFunction(name: kCAMediaTimingFunctionEaseOut)
valueLabel.layer.addAnimation(animation, forKey:"changeTextTransition")