iOS实现数字倍数动画效果

// 数字跳动动画
- (void)labelDanceAnimation:(NSTimeInterval)duration {
 //透明度
 CABasicAnimation *opacityAnimation = [CABasicAnimation animationWithKeyPath:@"opacity"];
 opacityAnimation.duration = 0.4 * duration;
 opacityAnimation.fromValue = @0.f;
 opacityAnimation.toValue = @1.f;

 //缩放
 CAKeyframeAnimation *scaleAnimation = [CAKeyframeAnimation animationWithKeyPath:@"transform.scale"];
 scaleAnimation.duration = duration;
 scaleAnimation.values = @[@3.f, @1.f, @1.2f, @1.f];
 scaleAnimation.keyTimes = @[@0.f, @0.16f, @0.28f, @0.4f];
 scaleAnimation.removedOnCompletion = YES;
 scaleAnimation.fillMode = kCAFillModeForwards;

 CAAnimationGroup *animationGroup = [CAAnimationGroup animation];
 animationGroup.animations = @[opacityAnimation, scaleAnimation];
 animationGroup.duration = duration;
 animationGroup.removedOnCompletion = YES;
 animationGroup.fillMode = kCAFillModeForwards;

 [self.comboLabel.layer addAnimation:animationGroup forKey:@"kComboAnimationKey"];
}

self.comboLabel.font = [UIFont fontWithName:@"AvenirNext-BoldItalic" size:50];

- (IBAction)clickAction:(UIButton *)sender {
 self.danceCount++;
 [self labelDanceAnimation:0.4];
 self.comboLabel.text = [NSString stringWithFormat:@"+ %tu",self.danceCount];
}