通过出生年月日计算年龄

NSString *birth = @"1993-03-03";

// 通过NSDateFormatter将NSString 转换成 NSDate 格式

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

[dateFormatter setDateFormat:@"yyyy-MM-dd"];

NSDate *date = [dateFormatter dateFromString:birth];

// 通过NSDateComponents 从 date 中提取出 年月日

NSDateComponents *components1 = [[NSCalendar currentCalendar] components:NSCalendarUnitYear | NSCalendarUnitMonth | NSCalendarUnitDay | NSCalendarUnitHour | NSCalendarUnitMinute | NSCalendarUnitSecond fromDate:date];

NSInteger year = [components1 year];

NSInteger month = [components1 month];

NSInteger day = [components1 day];

NSInteger hour = [components1 hour];

NSInteger minute = [components1 minute];

NSInteger second = [components1 second];

// 获取系统当前的年月日

NSDate *currentDate = [NSDate date]; // 获得系统的时间

NSDateComponents *components2 = [[NSCalendar currentCalendar] components:NSCalendarUnitYear | NSCalendarUnitMonth | NSCalendarUnitDay | NSCalendarUnitHour | NSCalendarUnitMinute | NSCalendarUnitSecond fromDate:currentDate];

NSInteger currentYear = [components2 year];

NSInteger currentMonth = [components2 month];

NSInteger currentDay = [components2 day];

// 计算年龄

NSInteger iAge = currentYear - year - 1;

if ((currentMonth > month) || (currentMonth == month && currentDay >= day)) {

iAge++;

}