IOS 点赞效果

前言：利用Button简单实现点赞动画

#pragma mark 动画- (void)btnAddAnimation:(UIButton *)btn{    CAKeyframeAnimation *k = [CAKeyframeAnimation animationWithKeyPath:@"transform.scale"];    k.values = @[@(0.1),@(1.0),@(1.5)];    k.keyTimes = @[@(0.0),@(0.5),@(0.8),@(1.0)];    k.calculationMode = kCAAnimationLinear;    [btn.layer addAnimation:k forKey:@"SHOW"];}