字符串转成NSDate类型，计算与当前时间的相差，年数，天数，时分秒……-优快云博客

 
        NSString 
         *dateStr= 
        @"2013-08-13 20:28:40" 
        ; 
        //传入时间 
       
 
        //将传入时间转化成需要的格式 
       
 
        NSDateFormatter 
         *format=[[ 
        NSDateFormatter 
         alloc 
        ] 
         init 
        ]; 
       
 
        [format 
         setDateFormat 
        : 
        @"yyyy-MM-dd HH:mm:ss" 
        ]; 
       
 
        NSDate 
         *fromdate=[format 
         dateFromString 
        :dateStr]; 
       
 
        NSTimeZone 
         *fromzone = [ 
        NSTimeZone 
         systemTimeZone 
        ]; 
       
 
        NSInteger 
         frominterval = [fromzone 
         secondsFromGMTForDate 
        : 
         fromdate 
        ]; 
       
 
        NSDate 
         *fromDate = [fromdate  
        dateByAddingTimeInterval 
        : 
         frominterval 
        ]; 
       
 
        NSLog( 
        @"fromdate=%@" 
        ,fromDate); 
       
 
        [format 
         release 
        ]; 
       
 
        //获取当前时间 
       
 
        NSDate 
         *date = [ 
        NSDate 
         date 
        ]; 
       
 
        NSTimeZone 
         *zone = [ 
        NSTimeZone 
         systemTimeZone 
        ]; 
       
 
        NSInteger 
         interval = [zone 
         secondsFromGMTForDate 
        : 
         date 
        ]; 
       
 
        NSDate 
         *localeDate = [date  
        dateByAddingTimeInterval 
        : 
         interval 
        ]; 
       
 
        NSLog( 
        @"enddate=%@" 
        ,localeDate); 
       
 
       
 
       
 
        double 
         intervalTime = [fromDate 
         timeIntervalSinceReferenceDate 
        ] - [localeDate 
         timeIntervalSinceReferenceDate 
        ]; 
       
 
       
 
        long 
         lTime = ( 
        long 
        )intervalTime; 
       
 
        NSInteger 
         iSeconds = lTime %  
        6 
        0 
        ; 
       
 
        NSInteger 
         iMinutes = (lTime /  
        6 
        0 
        ) %  
        6 
        0 
        ; 
       
 
        NSInteger 
         iHours = (lTime /  
        3 
        6 
        0 
        0 
        )$; 
       
 
        NSInteger 
         iDays = lTime/ 
        6 
        0 
        / 
        6 
        0 
        / 
        2 
        4 
        ; 
       
 
        NSInteger 
         iMonth = lTime/ 
        6 
        0 
        / 
        6 
        0 
        / 
        2 
        4 
        / 
        1 
        2 
        ; 
       
 
        NSInteger 
         iYears = lTime/ 
        6 
        0 
        / 
        6 
        0 
        / 
        2 
        4 
        / 
        3 
        8 
        4 
        ; 
       
 
       
 
        NSLog( 
        @"相差M年d月 或者 d日d时d分d秒" 
        , iYears,iMonth,iDays,iHours,iMinutes,iSeconds); 
       