Question

This is my first time comparing dates in Objective-C. I ve been searching the web for a while and all the examples I found involve building a NSDate from a string so I decided to ask a new question here... My question is as follows:

我需要知道两个NSDates是否在同一天, 忽略时间。我有两个 < code> NSAray 包含一套日期, 我需要逐一确定第一个 < code> NSAray 中的哪一个与第二个阵列中的同一天。

- (void)setActiveDaysColor:(UIColor *)activeDaysColor
{
    for (DayView *actualDay in _days)
    {
        NSDate *actualDayDate = [actualDay date];

        for (NSDate *activeDayDate in self.dates)
        {
            // Comparison code
            // If both dates are the same, tint actualDay with a different color
        }
    }
}

提前感谢您祝您今天愉快

亚历克斯。

Answer 1

通过略略时间组件创建新日期。并使用比较方法之一创建新日期

示例示例示例

NSCalendar *calendar = [NSCalendar currentCalendar];
NSInteger components = (NSDayCalendarUnit | NSMonthCalendarUnit | NSYearCalendarUnit);

NSDateComponents *firstComponents = [calendar components:components fromDate:firstDate];
NSDateComponents *secondComponents = [calendar components:components fromDate:secondDate];

NSDate *date1 = [calendar dateFromComponents:firstComponents];
NSDate *date2 = [calendar dateFromComponents:secondComponents];

NSComparisonResult result = [date1 compare:date2];
if (result == NSOrderedAscending) {
} else if (result == NSOrderedDescending) {
}  else {
}

Answer 2

-(BOOL)isSameDay:(NSDate*)date1 otherDay:(NSDate*)date2 {
NSCalendar* calendar = [NSCalendar currentCalendar];

unsigned unitFlags = NSYearCalendarUnit | NSMonthCalendarUnit |  NSDayCalendarUnit;
NSDateComponents* comp1 = [calendar components:unitFlags fromDate:date1];
NSDateComponents* comp2 = [calendar components:unitFlags fromDate:date2];

return [comp1 day]   == [comp2 day] &&
[comp1 month] == [comp2 month] &&
[comp1 year]  == [comp2 year];}

Answer 3

检查 SSDate 文档, 这是比较日期的方法

isEqualToDate
earlierDate
laterDate
compare

在您的情况中

if([actualDayDate isEqualToDate:activeDayDate])
{

}

Answer 4

Thanks for all your answers. I found a cleaner answer to my question answered in a totally unrelated post but that actually works perfectly.

if ((unsigned int)[actualDayDate timeIntervalSinceDate:activeDayDate] / 60 / 60 / 24 == 0)
{
     // do Stuff
}

Answer 5

相对于您代码中的循环, 您可以使用上游过滤所有今天的天体。过滤今天的日期是通过比较今天的开始和今天的结束来完成的。

您可以将任何 NSDate 设置为此日期的起始日期( 参见 < a href=" https:// stackoverflow. com/ a/1857392/ 608157" > 此答案 )

NSDate *beginDate = [NSDate date];
[[NSCalendar currentCalendar] rangeOfUnit:NSDayCalendarUnit startDate:&beginDate interval:NULL forDate:beginDate];

如果要获得结束日期, 您只需给它添加一天。 < enger > dont addate days by 计算秒数。这与日光节支没有关系。请按此方式( 另见 < a href= > https:// stackoverflow. com/ a/ 5067868/608157 > > this answord ):

NSDateComponents *oneDay = [[NSDateComponents alloc] init];
[oneDay setDay:1];
// one day after begin date
NSDate *endDate = [[NSCalendar currentCalendar] dateByAddingComponents:oneDay toDate:beginDate options:0];

既然你有两个日期来定义今天的范围, 你可以用NSPregister过滤你的所有日间意见, 来获取今天所有日内意见的新的阵列, 像这样(见

// filter DayViews to only include those where the day is today
NSArray *daysThatAreToday = [_days filteredArrayUsingPredicate:[NSPredicate predicateWithFormat:@"(date >= %@) AND (date <= %@)", beginDate, endDate]];

现在,您可以通过列出新的数组( 包含今天的 Day 视图), 对所有 Day 视图应用色调。

[daysThatAreToday enumerateObjectsUsingBlock:^(id obj, NSUInteger idx, BOOL *stop) {
    // Set the tint color here...
}];

在我看来,这是一个干净的<它们>,但更重要的是解决你问题的一种“强势”的正确方法。它读得很清楚,处理日光节约和其他日历,然后合并。如果你想在某个星期(或其他任何时间段)里加注所有日光观察,它也可以很容易被重新使用。

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