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[0]);
            NSString *timestring = [NSString stringWithFormat:@"%02d:%02d:%02d",(int)values[0]/60,(int)values[0]%60,(int)(values[0]*100)%100];
            _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 = @(1*60);   //从0开始
    anBasic.toValue = @(0);  //180秒
    anBasic.duration = 1*60;    //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 = 0; i<3; i++)
    {
        [attribute addAttributes:@{
                                   NSBackgroundColorAttributeName:[UIColor redColor],
                                   NSForegroundColorAttributeName:[UIColor whiteColor],
                                 
                                   }
                           range:NSMakeRange(3*i, 2)];
    }
    return  attribute;
}
@end