ios 公历转阴历

//农历转换函数//公历转农历(阴历)
+(NSString *)getChineseCalendarWithDate:(NSString *)dateString{
     NSDateFormatter *format = [[NSDateFormatter alloc] init];
     // 设置日期格式 为了转换成功
     format.dateFormat = @"yyyy-MM-dd";
     // NSString * -> NSDate *
     NSDate *solarDate = [format dateFromString:dateString];
     
     //天干名称
     NSArray *cTianGan= [NSArray arrayWithObjects:@"甲",@"乙",@"丙",@"丁",@"戊",@"己",@"庚",@"辛",@"壬",@"癸", nil];
     //地支名称
     NSArray *cDiZhi = [NSArray arrayWithObjects:@"子",@"丑",@"寅",@"卯",@"辰",@"巳",@"午",@"未",@"申",@"酉",@"戌",@"亥",nil];
     //属相名称
     NSArray *cShuXiang = [NSArray arrayWithObjects:@"鼠",@"牛",@"虎",@"兔",@"龙",@"蛇",@"马",@"羊",@"猴",@"鸡",@"狗",@"猪",nil];
     //农历日期名
     NSArray *cDayName = [NSArray arrayWithObjects:@"*",@"初一",@"初二",@"初三",@"初四",@"初五",@"初六",@"初七",@"初八",@"初九",@"初十",@"十一",@"十二",@"十三",@"十四",@"十五",@"十六",@"十七",@"十八",@"十九",@"二十",@"廿一",@"廿二",@"廿三",@"廿四",@"廿五",@"廿六",@"廿七",@"廿八",@"廿九",@"三十",nil];
     //农历月份名
     NSArray *cMonName = [NSArray arrayWithObjects:@"*",@"正",@"二",@"三",@"四",@"五",@"六",@"七",@"八",@"九",@"十",@"十一",@"腊",nil];
     //公历每月前面的天数
     const int wMonthAdd[12] = {0,31,59,90,120,151,181,212,243,273,304,334};
     //农历数据
     const int wNongliData[100] = {2635,333387,1701,1748,267701,694,2391,133423,1175,396438,3402,3749,331177,1453,694,201326,2350,465197,3221,3402,400202,2901,1386,267611,605,2349,137515,2709,464533,1738,2901,330421,1242,2651,199255,1323,529706,3733,1706,398762,2741,1206,267438,2647,1318,204070,3477,461653,1386,2413,330077,1197,2637,268877,3365,531109,2900,2922,398042,2395,1179,267415,2635,661067,1701,1748,398772,2742,2391,330031,1175,1611,200010,3749,527717,1452,2742,332397,2350,3222,268949,3402,3493,133973,1386,464219,605,2349,334123,2709,2890,267946,2773,592565,1210,2651,395863,1323,2707,265877};

     static NSInteger wCurYear,wCurMonth,wCurDay;
     static NSInteger nTheDate,nIsEnd,m,k,n,i,nBit;
     //取当前公历年、月、日
     NSDateComponents *components = [[NSCalendar currentCalendar] components:NSCalendarUnitDay | NSCalendarUnitMonth | NSCalendarUnitYear fromDate:solarDate];
     wCurYear = [components year];
     wCurMonth = [components month];
     wCurDay = [components day];
     //计算到初始时间1921年2月8日的天数：1921-2-8(正月初一)
     nTheDate = (wCurYear - 1921) * 365 + (wCurYear - 1921) / 4 + wCurDay + wMonthAdd[wCurMonth - 1] - 38;
     if((!(wCurYear % 4)) && (wCurMonth > 2)){
          nTheDate = nTheDate + 1;
     }
         
     //计算农历天干、地支、月、日
     nIsEnd = 0;
     m = 0;
     while(nIsEnd != 1){
          if(wNongliData[m] < 4095){
               k = 11;
          } else{
               k = 12;
          }
          n = k;
          while(n>=0)
          {
               //获取wNongliData(m)的第n个二进制位的值
               nBit = wNongliData[m];
               for(i=1;i<n+1;i++){
                    nBit =nBit/2;
               }
               nBit = nBit%2;
               if(nTheDate <= (29+nBit)){
                    nIsEnd = 1;
                    break;
               }
               nTheDate = nTheDate - 29 - nBit;
               n = n - 1;
          }
          if(nIsEnd){
               break;
          }
          m = m + 1;
     }
     wCurYear = 1921 + m;
     wCurMonth = k - n +1;
     wCurDay = nTheDate;
     if(k == 12){
          if(wCurMonth == wNongliData[m] / 65536 + 1){
               wCurMonth = 1 - wCurMonth;
          } else if (wCurMonth > wNongliData[m] /65536 + 1){
               wCurMonth = wCurMonth - 1;
          }
     }
     //生成农历天干、地支、属相
     NSString *szShuXiang = (NSString *)[cShuXiang objectAtIndex:((wCurYear - 4) % 60) % 12];
     NSString *szNongli = [NSString stringWithFormat:@"%@(%@%@)年",szShuXiang, (NSString *)[cTianGan objectAtIndex:((wCurYear - 4) % 60) % 10],(NSString *)[cDiZhi objectAtIndex:((wCurYear - 4) % 60) % 12]];

     //生成农历月、日
     NSString *szNongliDay;
     if (wCurMonth < 1){
          szNongliDay = [NSString stringWithFormat:@"闰%@",(NSString *)[cMonName objectAtIndex:-1 * wCurMonth]];
     } else{
          szNongliDay = (NSString *)[cMonName objectAtIndex:wCurMonth];
     }
     NSString *lunarDate = [NSString stringWithFormat:@"%@ %@月 %@",szNongli,szNongliDay,(NSString *)[cDayName objectAtIndex:wCurDay]];
     NSString *lunarDate1 = [NSString stringWithFormat:@"%@",(NSString *)[cDayName objectAtIndex:wCurDay]];
     return lunarDate1;
}

参照 iOS开发_公历转农历 - 简书 (jianshu.com)
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