做倒计时，秒转为时分秒

#pragma mark 秒-》HH-mm-ss

+(NSString *)timestrFromCount:(NSString*)timecount

{

    NSInteger secCount = [timecount integerValue];

    NSString *tmphh = [NSString stringWithFormat:@"%ld",secCount/3600];

    if ([tmphh length] == 1)

    {

        tmphh = [NSString stringWithFormat:@"0%@",tmphh];

    }

    NSString *tmpmm = [NSString stringWithFormat:@"%ld",(secCount/60)%60];

    if ([tmpmm length] == 1)

    {

        tmpmm = [NSString stringWithFormat:@"0%@",tmpmm];

    }

    NSString *tmpss = [NSString stringWithFormat:@"%ld",secCount%60];

    if ([tmpss length] == 1)

    {

        tmpss = [NSString stringWithFormat:@"0%@",tmpss];

    }

    return [NSString stringWithFormat:@"%@:%@:%@",tmphh,tmpmm,tmpss];

}