ios - 带有一周日期的 UITableview 标题栏？

Question

我怎样才能有UITableview日期的标题？

我知道我可以使用以下方法编辑标题：

self.title=@"meals for ..";

我想添加一周的日期。我怎样才能做到这一点？

Answer 1

你可以得到这样的日期：

NSDate *theDateToday = [NSDate date];

并像这样格式化：

NSDateFormatter *dateFormatter = [[NSDateFormatter alloc] init];
[dateFormatter setDateFormat:@"EEE MMM dd"];
NSString *theDateAsAString = [dateFormatter stringFromDate:theDateToday];

将其与您所拥有的相结合：

self.title = [NSString stringWithFormat:@"meals for %@", theDateAsAString];

---

至于查找星期几，您可以尝试调整这个答案。

- (NSString *)getWeekStartDateAsString:(NSDate *)date {

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

    NSDateComponents *components = [gregorian components:NSWeekdayCalendarUnit | NSYearCalendarUnit | NSMonthCalendarUnit | NSDayCalendarUnit fromDate:today];

    int dayofweek = [[[NSCalendar currentCalendar] components:NSWeekdayCalendarUnit fromDate:today] weekday];// this will give you current day of week

    [components setDay:([components day] - ((dayofweek) - 2))];// for beginning of the week.

    NSDate *beginningOfWeek = [gregorian dateFromComponents:components];
    NSDateFormatter *dateFormat_first = [[NSDateFormatter alloc] init];
    [dateFormat_first setDateFormat:@"yyyy-MM-dd"];
    dateString2Prev = [dateFormat stringFromDate:beginningOfWeek];

    weekstartPrev = [[dateFormat_first dateFromString:dateString2Prev] retain];

    return weekstartPrev;

}

- (NSString *)getWeekEndDateAsString:(NSDate *)date {

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

    NSDateComponents *componentsEnd = [gregorianEnd components:NSWeekdayCalendarUnit | NSYearCalendarUnit | NSMonthCalendarUnit | NSDayCalendarUnit fromDate:today];

    int Enddayofweek = [[[NSCalendar currentCalendar] components:NSWeekdayCalendarUnit fromDate:today] weekday];// this will give you current day of week

    [componentsEnd setDay:([componentsEnd day]+(7-Enddayofweek)+1)];// for end day of the week

    NSDate *EndOfWeek = [gregorianEnd dateFromComponents:componentsEnd];
    NSDateFormatter *dateFormat_End = [[NSDateFormatter alloc] init];
    [dateFormat_End setDateFormat:@"yyyy-MM-dd"];
    dateEndPrev = [dateFormat stringFromDate:EndOfWeek];

    weekEndPrev = [[dateFormat_End dateFromString:dateEndPrev] retain];

    return weekEndPrev;

}

您的最终结果可能如下所示：

self.title = [NSString stringWithFormat:@"meals for %@-%@", [self getWeekStartDateAsString:theDateToday], [self getWeekEndDateAsString:theDateToday]];

Answer 2

一种鲜为人知的 NSCalendar 方法将是 IMO 的最佳选择

rangeOfUnit:startDate:interval:forDate:. 它为您提供某个时间单位的开始和持续时间（间隔）。有了它，很容易在使用的日历中找到一周的开始，并添加 range-1 以获得该周最新的第二个。

localizedStringFromDate:dateStyle:timeStyle: _{使用在 OS X v10.6、iOS 4.0 中}也很少见的可用功能，很容易创建日期的本地化表示。

NSCalendar *cal = [NSCalendar currentCalendar];
NSDate *now = [NSDate date];
NSDate *startOfTheWeek;
NSDate *endOfWeek;
NSTimeInterval interval;
[cal rangeOfUnit:NSWeekCalendarUnit 
       startDate:&startOfTheWeek 
        interval:&interval 
         forDate:now];
//startOfWeek is 2013-06-02 22:00:00 +0000 now (note: it is GMT with timezone support for my timezone Europe/Berlin/DST)

endOfWeek = [startOfTheWeek dateByAddingTimeInterval:interval-1];
// 2013-06-09 21:59:59 +0000

NSString *text = [NSDateFormatter localizedStringFromDate:startOfTheWeek 
                                                dateStyle:NSDateFormatterShortStyle 
                                                timeStyle:NSDateFormatterNoStyle];
text = [text stringByAppendingString:@" to "];
text = [text stringByAppendingFormat:@"%@", [NSDateFormatter localizedStringFromDate:endOfWeek 
                                                                           dateStyle:NSDateFormatterShortStyle 
                                                                           timeStyle:NSDateFormatterNoStyle]];

self.title=text;

结果03.06.13 to 09.06.13适用于我的德语语言环境，星期一是一周的开始。