利用POPAnimatableProperty属性来实现动画倒计时

POPAnimatableProperty *prop = [POPAnimatableProperty propertyWithName:@"countdown" initializer:^(POPMutableAnimatableProperty *prop) {

        prop.writeBlock = ^(id obj,const CGFloat values[])
        {

            NSLog(@"%d",(int)values[]);
            NSString *timestring = [NSString stringWithFormat:@"%02d:%02d:%02d",(int)values[]/,(int)values[]%,(int)(values[]*)%];
            _lblTest.attributedText = [self formatterTime:timestring];
        };
    }];
    POPBasicAnimation *anBasic = [POPBasicAnimation linearAnimation];   //秒表当然必须是线性的时间函数
    anBasic.property = prop;    //自定义属性
    anBasic.fromValue = @(*);   //从0开始
    anBasic.toValue = @();  //180秒
    anBasic.duration = *;    //持续3分钟
    anBasic.beginTime = CACurrentMediaTime();    //延迟1秒开始
    [_lblTest pop_addAnimation:anBasic forKey:@"countdown"];

}
- (NSMutableAttributedString *)formatterTime:(NSString *)currentString
{

    NSMutableAttributedString *attribute = [[NSMutableAttributedString alloc]initWithString:currentString];
    for (NSInteger i = ; i<; i++)
    {
        [attribute addAttributes:@{
                                   NSBackgroundColorAttributeName:[UIColor redColor],
                                   NSForegroundColorAttributeName:[UIColor whiteColor],

                                   }
                           range:NSMakeRange(*i, )];
    }
    return  attribute;
}
@end