iPad的：动画UILabels变色 [英] iPad: Animate UILabels color changing

问题描述

我有一个弹出我的应用程序中显示点的标签。我使用下面的code，使标签得到较大规模，再小一点。我也想动画的颜色变化由紫色变为绿色。可有人点我的资源在实现这一目标？

  mLabel.textColor = [的UIColor purpleColor] [UIView的beginAnimations：无背景：NULL];
 [UIView的setAnimationDuration：1.0];
 [UIView的setAnimationDelegate：个体经营];
 mLabel.transform = CGAffineTransformMakeScale（1.5,1.5）;
 [UIView的setAnimationRepeatCount：1];
 mLabel.transform = CGAffineTransformMakeScale（0.5,0.5）;
 mLabel.textColor =的UIColor绿彩];
 [UIView的commitAnimations];
 

解决方案

不幸的是，颜色不与UIView的动画制作动画。
答案<一个href=\"http://stackoverflow.com/questions/2426614/how-to-animate-the-textcolor-property-of-an-uilabel\">this问题给一些很好的解决方法，而无需使用核心动画。

如果你不介意使用CATextLayer，而不是一个UILabel，那么颜色（和你的榜样缩放），可以是动画是这样的：

 ＃进口＆LT; QuartzCore / QuartzCore.h＆GT;
//还需要添加QuartzCore框架项目（以及进口）。
//
 - （无效）{animateTextLayerCGFloat的animationDuration = 5;CATextLayer * textLayer = [CATextLayer层]
[textLayer了setString：@Hello World的]。
[textLayer setForegroundColor：[的UIColor purpleColor] .CGColor]
[textLayer使用SetFontSize：30];
[textLayer SETFRAME：CGRectMake（20，200，300，40）];
[self.view层] addSublayer：textLayer];CABasicAnimation * colorAnimation = [CABasicAnimation
                                     animationWithKeyPath：@foregroundColor];
colorAnimation.duration = animationDuration;
colorAnimation.fillMode = kCAFillModeForwards;
colorAnimation.removedOnCompletion = NO;
colorAnimation.fromValue =（ID）的UIColor purpleColor] .CGColor;
colorAnimation.toValue =（ID）的UIColor绿彩] .CGColor;
colorAnimation.timingFunction = [CAMediaTimingFunction
                                 functionWithName：kCAMediaTimingFunctionLinear];CAKeyframeAnimation * scaleAnimation = [CAKeyframeAnimation
                                        animationWithKeyPath：@改造];
NSArray的* scaleValues​​ = [NSArray的arrayWithObjects：
    [NSValue valueWithCATransform3D：CATransform3DScale（textLayer.transform，1，1，1）]，
    [NSValue valueWithCATransform3D：CATransform3DScale（textLayer.transform，1.5，1.5，1）]，
    [NSValue valueWithCATransform3D：CATransform3DScale（textLayer.transform，0.5，0.5，1）]，零];
[scaleAnimation setValues​​方法：scaleValues​​];
scaleAnimation.fillMode = kCAFillModeForwards;
scaleAnimation.removedOnCompletion = NO;CAAnimationGroup * animationGroup = [CAAnimationGroup动画]
animationGroup.duration = animationDuration;
animationGroup.timingFunction = [CAMediaTimingFunction
                                functionWithName：kCAMediaTimingFunctionLinear];
animationGroup.fillMode = kCAFillModeForwards;
animationGroup.removedOnCompletion = NO;
animationGroup.animations =
        [NSArray的arrayWithObjects：colorAnimation，scaleAnimation，零][textLayer addAnimation：animationGroup forKey：@animateColorAndScale];
}
 

I have a label which pops up displaying points in my application. I am using the following code to make the label get larger in scale, then smaller. I would also like to animate the color changing from purple to green. Can someone point me to a resource in achieving this?

mLabel.textColor = [UIColor purpleColor];

 [UIView beginAnimations:nil context:NULL];
 [UIView setAnimationDuration:1.0];
 [UIView setAnimationDelegate:self];
 mLabel.transform = CGAffineTransformMakeScale(1.5,1.5);
 [UIView setAnimationRepeatCount:1];
 mLabel.transform = CGAffineTransformMakeScale(0.5,0.5);
 mLabel.textColor = [UIColor greenColor];
 [UIView commitAnimations];

解决方案

Unfortunately, the color doesn't animate with UIView animations. The answers to this question give some good workarounds without using Core Animation.

If you don't mind using a CATextLayer instead of a UILabel, then the color (and the scaling in your example) can be animated like this:

#import <QuartzCore/QuartzCore.h>
//Also need to add QuartzCore framework to project (as well as the import).
//
-(void)animateTextLayer {

CGFloat animationDuration = 5;

CATextLayer *textLayer = [CATextLayer layer];
[textLayer setString:@"Hello World"];
[textLayer setForegroundColor:[UIColor purpleColor].CGColor];
[textLayer setFontSize:30];
[textLayer setFrame:CGRectMake(20, 200, 300, 40)];
[[self.view layer] addSublayer:textLayer];

CABasicAnimation *colorAnimation = [CABasicAnimation 
                                     animationWithKeyPath:@"foregroundColor"];
colorAnimation.duration = animationDuration;
colorAnimation.fillMode = kCAFillModeForwards;
colorAnimation.removedOnCompletion = NO;
colorAnimation.fromValue = (id)[UIColor purpleColor].CGColor;
colorAnimation.toValue = (id)[UIColor greenColor].CGColor;
colorAnimation.timingFunction = [CAMediaTimingFunction 
                                 functionWithName:kCAMediaTimingFunctionLinear];

CAKeyframeAnimation *scaleAnimation = [CAKeyframeAnimation 
                                        animationWithKeyPath:@"transform"];
NSArray *scaleValues = [NSArray arrayWithObjects:
    [NSValue valueWithCATransform3D:CATransform3DScale(textLayer.transform, 1, 1, 1)],
    [NSValue valueWithCATransform3D:CATransform3DScale(textLayer.transform, 1.5, 1.5, 1)],
    [NSValue valueWithCATransform3D:CATransform3DScale(textLayer.transform, 0.5, 0.5, 1)], nil];
[scaleAnimation setValues:scaleValues]; 
scaleAnimation.fillMode = kCAFillModeForwards;
scaleAnimation.removedOnCompletion = NO;

CAAnimationGroup *animationGroup = [CAAnimationGroup animation];
animationGroup.duration = animationDuration;
animationGroup.timingFunction = [CAMediaTimingFunction 
                                functionWithName:kCAMediaTimingFunctionLinear];
animationGroup.fillMode = kCAFillModeForwards;
animationGroup.removedOnCompletion = NO;
animationGroup.animations = 
        [NSArray arrayWithObjects:colorAnimation, scaleAnimation, nil];

[textLayer addAnimation:animationGroup forKey:@"animateColorAndScale"];
}

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