如何设置UILabel的背景颜色动画？

Question

这看起来应该可以,但不是.颜色立刻变为绿色.

self.labelCorrection.backgroundColor = [UIColor whiteColor];
[UIView animateWithDuration:2.0 animations:^{
    self.labelCorrection.backgroundColor = [UIColor greenColor];
}];

Answer 1

我找不到它的任何地方记录,但它出现的backgroundColor财产UILabel不能设置动画,因为你的代码工作正常与香草UIView.但是,只要您不设置标签视图本身的背景颜色,此hack似乎可以正常工作:

#import <QuartzCore/QuartzCore.h>

...

theLabel.layer.backgroundColor = [UIColor whiteColor].CGColor;

[UIView animateWithDuration:2.0 animations:^{
    theLabel.layer.backgroundColor = [UIColor greenColor].CGColor;
} completion:NULL];

Answer 2

迅速

1. (重要)将UILabel的背景颜色设置为清除(在IB或代码中).例如:

   override func viewDidLoad() {
       super.viewDidLoad()
   
       myLabel.backgroundColor = UIColor.clear
   }
   

2. 为图层背景颜色设置动画.

   @IBAction func animateButtonTapped(sender: UIButton) {
   
       UIView.animate(withDuration: 1.0, animations: {
           self.myLabel.layer.backgroundColor = UIColor.red.cgColor
       })
   }
   

注意CGColor在之后添加UIColor.

结果

Answer 3

你可以动画它,但我必须首先(编程)将它设置为clearColor由于某种原因.没有它,动画要么不起作用,要么不可见.

我在自定义表格单元格中设置UILabel的背景颜色.这是willDisplayCell方法中的代码.我不会尝试在cellForRow中设置动画,因为很多布局都被表格修改了.

- (void)tableView:(UITableView *)tableView willDisplayCell:(UITableViewCell *)cell forRowAtIndexPath:(NSIndexPath *)indexPath
{
        ((RouteListCell *)cell).name.backgroundColor = [UIColor clearColor];
        [((RouteListCell *)cell).name backgroundGlowAnimationFromColor:[UIColor whiteColor] toColor:[UIColor redColor] clearAnimationsFirst:YES];
}

这是我的动画例程:

-(void) backgroundGlowAnimationFromColor:(UIColor *)startColor toColor:(UIColor *)destColor clearAnimationsFirst:(BOOL)reset;
{
    if (reset)
    {
        [self.layer removeAllAnimations];
    }

    CABasicAnimation *anAnimation = [CABasicAnimation animationWithKeyPath:@"backgroundColor"];
    anAnimation.duration = 1.00;
    anAnimation.repeatCount = HUGE_VAL;
    anAnimation.autoreverses = YES;
    anAnimation.fromValue = (id) startColor.CGColor; // [NSNumber numberWithFloat:1.0];
    anAnimation.toValue = (id) destColor.CGColor; //[NSNumber numberWithFloat:0.10];
    [self.layer addAnimation:anAnimation forKey:@"backgroundColor"];
}

Answer 4

斯威夫特3

要将标签背景颜色从白色设置为绿色,请按以下方式设置标签:

self.labelCorrection.backgroundColor = UIColor.clear
self.labelCorrection.layer.backgroundColor = UIColor.white.cgColor

像这样的动画:

UIView.animate(withDuration: 2.0) { 
    self.labelCorrection.layer.backgroundColor = UIColor.green.cgColor
}

要返回原始状态,以便再次设置动画,请确保删除动画:

self.labelCorrection.layer.backgroundColor = UIColor.white.cgColor
self.labelCorrection.layer.removeAllAnimations()