［转载］计算设定时间点与当前时间差的代码

利用时间戳来准确计算某个时间点具现在的时间差，可以参考 CocoaChina 会员 “” 分享的下面这段代码

- (NSString *)intervalSinceNow: (NSString *) theDate 

{

    

    NSDateFormatter *date=[[NSDateFormatter alloc] init];

    [date setDateFormat:@"yyyy-MM-dd HH:mm:ss"];

    NSDate *d=[date dateFromString:theDate];

    

    NSTimeInterval late=[d timeIntervalSince1970]*1;

    

    

    NSDate* dat = [NSDate dateWithTimeIntervalSinceNow:0];

    NSTimeInterval now=[dat timeIntervalSince1970]*1;

    NSString *timeString=@"";

    

    NSTimeInterval cha=now-late;

    

    if (cha/3600<1) {

        timeString = [NSString stringWithFormat:@"%f", cha/60];

        timeString = [timeString substringToIndex:timeString.length-7];

        timeString=[NSString stringWithFormat:@"%@分钟前", timeString];

        

    }

    if (cha/3600>1&&cha/86400<1) {

        timeString = [NSString stringWithFormat:@"%f", cha/3600];

        timeString = [timeString substringToIndex:timeString.length-7];

        timeString=[NSString stringWithFormat:@"%@小时前", timeString];

    }

    if (cha/86400>1)

    {

        timeString = [NSString stringWithFormat:@"%f", cha/86400];

        timeString = [timeString substringToIndex:timeString.length-7];

        timeString=[NSString stringWithFormat:@"%@天前", timeString];

        

    }

    [date release];

    return timeString;

}