Month value coming wrong for a specified date? - ios

Question

Following is my code:
NSDateComponents *componenetsForEnd = [[NSCalendar currentCalendar] components:NSWeekdayCalendarUnit | NSCalendarUnitDay | NSCalendarUnitMonth | NSCalendarUnitYear fromDate:endDate];
NSInteger endDay = [componenetsForEnd day];
NSInteger endMonth = [componenetsFoeEnd month];
NSInteger endDayValue = componenetsForEnd.weekday;
Now: when endDate = 2015-08-31 23:59:59 +0000, I am getting month as 9! This is causing wrong endDayValue. What is going wrong here?
EDIT:
Here is how I calculate endDate :
NSDate *endDate = [self endOfMonthForDate:todayDate];
this method takes today's date with [NSDate date] and this is how it goes:
- (NSDate *) dateByAddingMonths: (NSInteger) monthsToAdd andDate: (NSDate *)date
{
NSCalendar * calendar = [NSCalendar currentCalendar];
[calendar setTimeZone:[NSTimeZone systemTimeZone]];
NSDateComponents * months = [[NSDateComponents alloc] init];
[months setMonth: monthsToAdd];
return [calendar dateByAddingComponents: months toDate: date options: 0];
}
- (NSDate *) endOfMonthForDate: (NSDate *)date
{
NSCalendar * calendar = [NSCalendar currentCalendar];
[calendar setTimeZone:[NSTimeZone systemTimeZone]];
NSDate * plusOneMonthDate = [self dateByAddingMonths: 1 andDate:date];
NSDateComponents * plusOneMonthDateComponents = [calendar components: NSYearCalendarUnit | NSMonthCalendarUnit fromDate: plusOneMonthDate];
NSDate * endOfMonth1 = [[calendar dateFromComponents: plusOneMonthDateComponents] dateByAddingTimeInterval: -1]; // One second before the start of next month
NSTimeZone* sourceTimeZone = [NSTimeZone timeZoneWithAbbreviation:#"GMT"];
NSTimeZone* destinationTimeZone = [NSTimeZone systemTimeZone];
NSInteger sourceGMTOffset = [sourceTimeZone secondsFromGMTForDate:endOfMonth1];
NSInteger destinationGMTOffset = [destinationTimeZone secondsFromGMTForDate:endOfMonth1];
NSTimeInterval interval = destinationGMTOffset - sourceGMTOffset;
NSDate* endOfMonth = [[NSDate alloc] initWithTimeInterval:interval sinceDate:endOfMonth1];
return endOfMonth;
}
Also tried performing these actions to make NSDateComponents and NSDate with dateFormatter in systemTimeZone:
NSDateFormatter *dateFormatter = [[NSDateFormatter alloc]init];
[dateFormatter setTimeZone:[NSTimeZone systemTimeZone]];
dateFormatter.dateFormat = #"yyyy-MM-dd HH:mm:ss";
NSString *endDateString = [dateFormatter stringFromDate:endDate];
NSDateFormatter *dateFormatter2 = [[NSDateFormatter alloc]init];
[dateFormatter2 setTimeZone:[NSTimeZone systemTimeZone]];
dateFormatter2.dateFormat = #"yyyy-MM-dd HH:mm:ss";
NSDate *endDateProper = [dateFormatter2 dateFromString:endDateString];
NSCalendar *greCalendar = [[NSCalendar alloc] initWithCalendarIdentifier:NSGregorianCalendar];
NSDateComponents *componenetsForEnd = [greCalendar components:NSWeekdayCalendarUnit | NSCalendarUnitDay | NSCalendarUnitMonth | NSCalendarUnitYear fromDate:endDateProper];
[componenetsForEnd setTimeZone:[NSTimeZone systemTimeZone]];

Answer 1

Instead of using current calendar
[NSCalendar currentCalendar]
you can use:
NSCalendar *greCalendar = [[NSCalendar alloc] initWithCalendarIdentifier:NSGregorianCalendar];

Answer 2

The problem was with the fact that I think is this way: When calculating a day, month or Hour, minute and second , you need to specify that timezone for dateComponents is UTC i.e. GMT. However, my endDateProper which is in system timezone.
So, doing this did the trick for me:
NSDateComponents *componenetsForEnd = [greCalendar componentsInTimeZone:[NSTimeZone timeZoneWithAbbreviation:#"UTC"] fromDate:endDateProper];