IOS NSDateFormatter 和NSDateComponents

//处理时间的方法

dateString 可以是从model请求下来的 数据结构， 我的是从XML解析出来的 数据，有两种数据结构，所以，处理了一下，

- (NSString *)getChinaDate:(NSString *) dateString{

    

    NSMutableArray *dateArr = [NSMutableArrayarrayWithArray:[dateString componentsSeparatedByCharactersInSet:[NSCharacterSetcharacterSetWithCharactersInString:@"-/ :"]]];

    [dateArr removeObject:@""];

    [dateArr removeObject:@" "];

    NSMutableString *dateStr = [NSMutableStringstring];

    for (int i = 0; i < dateArr.count; i++) {

        [dateStr appendString:dateArr[i]];

        if (i<dateArr.count-1) {

            [dateStr appendString:@"/"];

        }

    }

    

    NSDateFormatter *dateformatter = [[[NSDateFormatteralloc]init] autorelease];//定义NSDateFormatter用来显示格式

    [dateformatter setDateFormat:@"yyyy/MM/dd/HH/mm/ss"];//设定格式

    NSCalendar *cal = [NSCalendarcurrentCalendar];//定义一个NSCalendar对象

    

    NSDate *todate = [dateformatter dateFromString:dateStr];

    

    NSDate *today = [NSDatedate];//得到当前时间

    //用来得到具体的时差

    unsignedint unitFlags = NSYearCalendarUnit |NSMonthCalendarUnit | NSDayCalendarUnit |NSHourCalendarUnit | NSMinuteCalendarUnit |kCFCalendarUnitSecond;

    NSDateComponents *comps = [cal components:unitFlags fromDate:todate toDate:today options:0];

    

    if ([comps year]>0) {

        return [NSStringstringWithFormat:@"%d年前",[comps year]];

    }else if ([compsmonth]>0) {

        return [NSStringstringWithFormat:@"%d月前",[compsmonth]];

    }else if ([compsday]>0) {

        return [NSStringstringWithFormat:@"%d天前",[comps day]];

    }else if ([compshour]>0) {

        return [NSStringstringWithFormat:@"%d小时前",[comps hour]];

    }else if ([compsminute]>0) {

        return [NSStringstringWithFormat:@"%d分钟前",[comps minute]];

    } else {

        return @"1分钟";

    }

}