指定日期的月值错误？

Question

以下是我的代码：

NSDateComponents *componenetsForEnd = [[NSCalendar currentCalendar] components:NSWeekdayCalendarUnit | NSCalendarUnitDay | NSCalendarUnitMonth | NSCalendarUnitYear fromDate:endDate];
NSInteger endDay = [componenetsForEnd day];
NSInteger endMonth = [componenetsFoeEnd month];
NSInteger endDayValue = componenetsForEnd.weekday;

现在：当 endDate = 2015-08-31 23:59:59 +0000 时，我得到的月份是 9！这会导致错误的 endDayValue。这里出了什么问题？

编辑：

这是我计算结束日期的方法：

NSDate *endDate = [self endOfMonthForDate:todayDate];

此方法使用今天的日期 [NSDate date]，它是这样的：

- (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;
}

还尝试执行这些操作以在 systemTimeZone 中使用 dateFormatter 创建 NSDateComponents 和 NSDate：

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

而不是使用当前日历

[NSCalendar currentCalendar]

您可以使用：

NSCalendar *greCalendar = [[NSCalendar alloc] initWithCalendarIdentifier:NSGregorianCalendar];

Answer 2

问题出在我认为是这样的事实：在计算日、月或小时、分钟和秒时，您需要指定 dateComponents 的时区是 UTC，即 GMT。但是，我的 endDateProper 在系统时区。

所以，这样做对我有用：

NSDateComponents *componenetsForEnd = [greCalendar componentsInTimeZone:[NSTimeZone timeZoneWithAbbreviation:@"UTC"] fromDate:endDateProper];

指定日期的月值错误？

Month value coming wrong for a specified date?

calendar

objective-c

nsdate

nsdatecomponents

ios