iOS獲取某個日期後n個月的日期

 1 -(NSDate *)getPriousorLaterDateFromDate:(NSDate *)date withMonth:(NSInteger)month
 2  
 3 {
 4  
 5     NSDateComponents *comps = [[NSDateComponents alloc] init];
 6  
 7     [comps setMonth:month];
 8  
 9     NSCalendar *calender = [[NSCalendar alloc] initWithCalendarIdentifier:NSCalendarIdentifierGregorian];
10  
11     NSDate *mDate = [calender dateByAddingComponents:comps toDate:date options:0];
12  
13  
14     return mDate;
15  
16 }

 1 - (NSDate *)getLaterDateFromDate:(NSDate *)date withYear:(NSInteger)year month:(NSInteger)month day:(NSInteger)day {
 2     NSCalendar *calendar = [[NSCalendar alloc] initWithCalendarIdentifier:NSCalendarIdentifierGregorian];
 3  
 4     NSDateComponents *comps = nil;
 5  
 6     comps = [calendar components:NSCalendarUnitYear | NSCalendarUnitMonth | NSCalendarUnitDay fromDate:date];
 7  
 8     NSDateComponents *adcomps = [[NSDateComponents alloc] init];
 9  
10     [adcomps setYear:year];
11  
12     [adcomps setMonth:month];
13  
14     [adcomps setDay:day];
15  
16     NSDate *newdate = [calendar dateByAddingComponents:adcomps toDate:date options:0];
17  
18     return newdate;
19 }