objective-c - 一周内所有 NSDate 的数组

Question

我想要一个函数，该函数将周数作为输入并返回该特定周创建的所有 NSDate 的数组。

像这样:

-(NSArray*)allDatesInWeek:(int)weekNumber {
    NSDate *today = [NSDate date];
    NSCalendar *calendar = [[NSCalendar alloc] initWithCalendarIdentifier:NSGregorianCalendar];
    [calendar setFirstWeekday:2];
    NSDateComponents *todayComp = [calendar components:NSYearCalendarUnit fromDate:today];
    int currentyear = todayComp.year;
    /* Calculate and return the date of weekNumber for current year */

如何以简单的方式做到这一点？

Answer 1

这个解决方案完全依赖于 NSCalendar，没有对用户的日历做任何假设。

-(NSArray*)allDatesInWeekContainingDate:(NSDate*)referenceDate {
    NSCalendar *calendar = [NSCalendar currentCalendar];
    NSInteger ordinalityOfInput = [calendar ordinalityOfUnit:NSWeekdayCalendarUnit
                                                      inUnit:NSWeekCalendarUnit
                                                     forDate:referenceDate];
    NSDateComponents *componentsToAdd = [[NSDateComponents alloc] init];
    componentsToAdd.day = -1 * (ordinalityOfInput - 1);
    NSDate *startDate = [calendar dateByAddingComponents:componentsToAdd toDate:referenceDate options:0];
    NSInteger numDaysInWeek = [calendar maximumRangeOfUnit:NSWeekdayCalendarUnit].length;
    NSMutableArray *allDays = [NSMutableArray arrayWithCapacity:numDaysInWeek];
    NSDateComponents *curDayOffset = [[NSDateComponents alloc] init];
    for (int curDay=0; curDay < numDaysInWeek; curDay++) {
        curDayOffset.day = curDay;
        [allDays addObject:[calendar dateByAddingComponents:curDayOffset toDate:startDate options:0]];
    }
    return allDays;
}