날짜 월을 정식으로 변환하려고 시도하면 (null)

Question

다음 코드를 사용하여 월 (5)을 전체 이름 (5 월)으로 변환하려고합니다. 그러나 설정을 MM에서 MMMM으로 변경하면 null이 반환됩니다. 왜 이런거야?

NSDate *date = [birthday getDate]; 
NSDateComponents *components = [[NSCalendar currentCalendar] components:NSDayCalendarUnit | NSMonthCalendarUnit | NSYearCalendarUnit fromDate:date]; 
NSInteger year = [components year]; 

if (year == 1604) { 
    NSString *monthNumberString = [NSString stringWithFormat:@"%d", [components month]]; 
    NSDateFormatter *formatter = [[NSDateFormatter alloc] init]; 
    [formatter setDateFormat:@"MMMM"]; 
    NSDate *date = [formatter dateFromString:monthNumberString]; 
    NSString *stringFromDate = [formatter stringFromDate:date]; 
    NSString *monthDay = [NSString stringWithFormat:@"%@, %d", stringFromDate, [components day]]; 
    cell.birthdayLabel.text = monthDay; 
} else { 
... 
} 

Answer 1

당신은 이미 날짜가

NSDate *date = [birthday getDate]; 
NSDateComponents *components = [[NSCalendar currentCalendar] components:NSDayCalendarUnit | NSMonthCalendarUnit | NSYearCalendarUnit 
                   fromDate:date]; 
NSInteger year = [components year]; 

if (year == 1604) 
{ 
    NSString *monthNumberString = [NSString stringWithFormat:@"%d", [components month]]; 
    NSDateFormatter *formatter = [[NSDateFormatter alloc] init]; 
    [formatter setDateFormat:@"MM"]; 
    NSDate *date = [formatter dateFromString:monthNumberString]; 
    [formatter setDateFormat:@"MMMM"]; 
    NSString *stringFromDate = [formatter stringFromDate:date]; 
    NSString *monthDay = [NSString stringWithFormat:@"%@, %d", stringFromDate, [components day]]; 

    NSLog(@"%@",monthDay); 

    cell.birthdayLabel.text = monthDay; 
} 
else { 

} 

Answer 2

보십시오. 그냥 포맷 :

NSDate *date = [birthday getDate]; 
NSDateComponents *components = [[NSCalendar currentCalendar] components:NSDayCalendarUnit | NSMonthCalendarUnit | NSYearCalendarUnit fromDate:date]; 
NSInteger year = [components year]; 

if (year == 1604) { 
    NSDateFormatter *formatter = [[NSDateFormatter alloc] init]; 
    [formatter setDateFormat:@"MMMM, d"]; 
    NSString *stringFromDate = [formatter stringFromDate:date]; 
    cell.birthdayLabel.text = stringFromDate; 
} else { 
... 
}