正确使用 NSDateComponents

发布于 2024-12-01 08:03:17 字数 478 浏览 1 评论 0原文

我一直在关注苹果文档以及这里的一些代码，但我似乎无法让 NSDateComponents 正常工作。

NSCalendar* calendar = [[NSCalendar alloc] initWithCalendarIdentifier:NSGregorianCalendar];
NSDateComponents *components = [calendar components:(NSHourCalendarUnit|NSMinuteCalendarUnit) fromDate:dateValue];
[calendar release];

dateValue 是某个日期，我只关心它的时间，时间是 8:00AM。当我检查此后的组件时，小时和分钟都为零。

我也尝试插入这个，因为我读到你需要（虽然不是每个例子都有这个）：

[components setCalendar:calendar];

原文

I've been following the apple docs as well as some code on here and I can't seem to get NSDateComponents to work correctly.

NSCalendar* calendar = [[NSCalendar alloc] initWithCalendarIdentifier:NSGregorianCalendar];
NSDateComponents *components = [calendar components:(NSHourCalendarUnit|NSMinuteCalendarUnit) fromDate:dateValue];
[calendar release];

dateValue is some date, I only care about the time of it, and the time is 8:00AM. When I check what components is after this, Hour and Minute are both nil.

I also tried inserting this, because I read that you needed to (although not every example has this):

[components setCalendar:calendar];

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温柔女人霸气范 2024-12-08 08:03:17

该代码将起作用。也许是因为您试图错误地访问小时和分钟。我这样做了，并在控制台窗口中获取了当前的小时和分钟：

NSDate *dateValue = [NSDate date];
NSCalendar* calendar = [[NSCalendar alloc] initWithCalendarIdentifier:NSGregorianCalendar];
NSDateComponents *components = [calendar components:(NSHourCalendarUnit|NSMinuteCalendarUnit) fromDate:dateValue];
NSLog(@"hour: %d, minute: %d", [components hour], [components minute]);
[calendar release];

-hour 和 -min 返回普通整数，而不是 NSNumber 对象。

从 ios8 开始，上面的类常量已被弃用，使用下面的代码：

NSDate *dateValue = [NSDate date];
NSCalendar* calendar = [[NSCalendar alloc] initWithCalendarIdentifier:NSCalendarIdentifierGregorian];
NSDateComponents *components = [calendar components:(NSCalendarUnitHour|NSCalendarUnitMinute) fromDate:dateValue];
NSLog(@"hour: %ld, minute: %d", (long)[components hour], [components minute]);

That code will work. Maybe it's because you're trying to access the hour and minute incorrectly. I did this and got the current hour and minute in the Console window:

NSDate *dateValue = [NSDate date];
NSCalendar* calendar = [[NSCalendar alloc] initWithCalendarIdentifier:NSGregorianCalendar];
NSDateComponents *components = [calendar components:(NSHourCalendarUnit|NSMinuteCalendarUnit) fromDate:dateValue];
NSLog(@"hour: %d, minute: %d", [components hour], [components minute]);
[calendar release];

-hour and -minute return plain integers, not NSNumber objects.

From ios8 onwards above class constant is deprecated, use below code:

NSDate *dateValue = [NSDate date];
NSCalendar* calendar = [[NSCalendar alloc] initWithCalendarIdentifier:NSCalendarIdentifierGregorian];
NSDateComponents *components = [calendar components:(NSCalendarUnitHour|NSCalendarUnitMinute) fromDate:dateValue];
NSLog(@"hour: %ld, minute: %d", (long)[components hour], [components minute]);

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