iOS 时间计算

获取6个月之后的时间

NSCalendar *calendar = [[NSCalendar alloc] initWithCalendarIdentifier:NSGregorianCalendar];
                
                NSDateComponents *comps = nil;
                
                comps = [calendar components:NSYearCalendarUnit|NSMonthCalendarUnit|NSDayCalendarUnit fromDate:tran.transactionDate];
                
                NSDateComponents *adcomps = [[NSDateComponents alloc] init];
                
                [adcomps setYear:0];
                
                [adcomps setMonth:6];
                
                [adcomps setDay:0];
                NSDate *newdate = [calendar dateByAddingComponents:adcomps toDate:tran.transactionDate options:0];