是否有推荐的方法使NSDatePicker使用我的步长？

Question

我想知道你们中有些人是否可以就此提出建议。

我正在尝试将NSDatePicker的步长更改为另一个值而不是1。 最重要的是，我发现步进分钟不会改变时间，也不会改变一天。

我正在使用委托方法datePickerCell：validateProposedDateValue：timeInterval：。

现在，虽然它确实按预期工作，整个事情看起来如此之多，以至于我开始怀疑是否有更简单的方法来实现这一目标。

对文档的任何建议或指示表示赞赏。谢谢。

这是我的代码：

- (void)datePickerCell:(NSDatePickerCell *)aDatePickerCell validateProposedDateValue:(NSDate **)proposedDateValue
          timeInterval:(NSTimeInterval *)proposedTimeInterval {
    DLog(@"date picker for: %@", [aDatePickerCell identifier]);
    NSDate *newProposedDateValue = nil;
    // just in case that we don't need a correction
    NSDate *correctedProposedDateValue = *proposedDateValue;

    // the interval that the step generates
    // > 0 means: the old date is later than the new proposed date
    // < 0 means: the old date is earlier than the new proposed date
    int interval = [[self dateValue] timeIntervalSinceDate:*proposedDateValue];

    // define expected interval values for our scenarios
    // we don't care about a minute step that does not cross the hour here
    // nor do we care about an hour step that does not cross the day

    // minutes are stepped:    minute is stepped but hour remains (01:59 <-> 01:00), so the difference is 59 minutes
    int const minuteSteppedUpAcrossHour   = -59 *60;
    int const minuteSteppedDownAcrossHour = - minuteSteppedUpAcrossHour;
    // nor do we care about an hour step that does not cross the day
    // hours are stepped:      hour is stepped but day remains (10.03.13 00:30 <-> 10.03.13 23:30) we have a difference of 23 hours
    int const hourSteppedUpAcrossDay      = -23 *60 *60;
    int const hourSteppedDownAcrossDay    = - hourSteppedUpAcrossDay;

    // define correction values for our scenarios
    int const anHour = 60 *60;
    int const aDay = anHour *24;

    switch (interval) {
        case hourSteppedUpAcrossDay:
            correctedProposedDateValue = [*proposedDateValue dateByAddingTimeInterval:(-aDay)];
            break;
        case minuteSteppedDownAcrossHour:
            correctedProposedDateValue = [*proposedDateValue dateByAddingTimeInterval:(+anHour)];
            break;
        case hourSteppedDownAcrossDay:
            correctedProposedDateValue = [*proposedDateValue dateByAddingTimeInterval:(+aDay)];
            break;
        case minuteSteppedUpAcrossHour:
            correctedProposedDateValue = [*proposedDateValue dateByAddingTimeInterval:(-anHour)];
            break;

        default:
            break;
    }
    if ([self dateValue] < correctedProposedDateValue) {
        newProposedDateValue = [self roundDateUpForMinuteIntervalConstraint:correctedProposedDateValue];
    } else {
        newProposedDateValue = [self roundDateDownForMinuteIntervalConstraint:correctedProposedDateValue];
    }
    *proposedDateValue = newProposedDateValue;
}

- (NSDate *)roundDateUpForMinuteIntervalConstraint:(NSDate *)date {
    return [self date:date roundedUpToMinutes:MINUTE_INTERVAL_CONSTRAINT_FOR_SESSIONS_START];
}

- (NSDate *)roundDateDownForMinuteIntervalConstraint:(NSDate *)date {
    return [self date:date roundedDownToMinutes:MINUTE_INTERVAL_CONSTRAINT_FOR_SESSIONS_START];
}

- (NSDate *)date:(NSDate *)date roundedUpToMinutes:(int)minutes {
    // Strip miliseconds by converting to int
    int referenceTimeInterval = (int)[date timeIntervalSinceReferenceDate];
    int remainingSeconds = referenceTimeInterval %(60 *minutes);
    int timeRoundedUpToMinutes = 0;
    if (remainingSeconds== 0) {
        timeRoundedUpToMinutes = referenceTimeInterval;
    } else {
        timeRoundedUpToMinutes = referenceTimeInterval -remainingSeconds +(60 *minutes);
    }

    return [NSDate dateWithTimeIntervalSinceReferenceDate:(NSTimeInterval)timeRoundedUpToMinutes];
}

- (NSDate *)date:(NSDate *)date roundedDownToMinutes:(int)minutes {
    // Strip miliseconds by converting to int
    int referenceTimeInterval = (int)[date timeIntervalSinceReferenceDate];
    int remainingSeconds = referenceTimeInterval %(60 *minutes);
    int timeRoundedUpToMinutes = referenceTimeInterval -remainingSeconds;

    return [NSDate dateWithTimeIntervalSinceReferenceDate:(NSTimeInterval)timeRoundedUpToMinutes];
}