iPad:动画 UILabels 颜色变化 [英] iPad: Animate UILabels color changing
问题描述
我有一个标签,它会在我的应用程序中弹出显示点.我正在使用以下代码使标签变大,然后变小.我还想为颜色从紫色变为绿色设置动画.有人可以为我指出实现这一目标的资源吗?
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];
推荐答案
遗憾的是,UIView 动画中没有颜色动画.这个问题的答案提供了一些很好的解决方法,而无需使用核心动画.
Unfortunately, the color doesn't animate with UIView animations. The answers to this question give some good workarounds without using Core Animation.
如果您不介意使用 CATextLayer 而不是 UILabel,那么颜色(以及示例中的缩放)可以像这样设置动画:
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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