Objective c 给定一年和一周的数字，你如何得到一周中第一天的日期？

我需要这个来获取一周的图表数据。这个不适合我。它返回的日期是所选年份的1月1日。有什么想法吗

-(NSDate*) getFirstDateOfTheWeek:(NSString*) weekNr andYear: (NSString*) theYear {
        int intYear = [theYear intValue];
        int intWeek = [weekNr intValue];

        NSCalendar *gregorian = [[NSCalendar alloc]
                                 initWithCalendarIdentifier:NSGregorianCalendar];
        [gregorian setLocale:[NSLocale currentLocale]];

        NSDateComponents * comp = [[NSDateComponents alloc] init];
        [comp setYear:intYear];
        [comp setWeek:intWeek];

        NSDate *dateOfFirstDay = [gregorian dateFromComponents:comp];
        NSDateComponents *dateComponents =
        [gregorian components:NSWeekdayCalendarUnit|NSWeekCalendarUnit|NSDayCalendarUnit|NSYearCalendarUnit|NSMonthCalendarUnit fromDate:dateOfFirstDay];
        int year = [dateComponents year];
        int month = [dateComponents month];
        int day = [dateComponents day];

        dateOfFirstDay= [gregorian dateFromComponents:dateComponents];
        return dateOfFirstDay;
    }

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除了setYear和setWeek之外，还应该在nsdate组件中设置weekday

[comp setWeekday:intWeek];

然后，在获取新组件时，您不需要很多标记，因为您只需要一天（以及调试所需的其他时间）：

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伟大的。我认为工作日是一周中的一天，就像周一周日。这是一周的第一天还是最后一天？

    [gregorian components:NSDayCalendarUnit|NSYearCalendarUnit|NSMonthCalendarUnit fromDate:dateOfFirstDay];