获得一个月的最后一天

Question

我怎样才能获得当月的最后一天NSDate？

Answer 1

NSDate *curDate = [NSDate date];
NSCalendar* calendar = [NSCalendar currentCalendar];
NSDateComponents* comps = [calendar components:NSYearCalendarUnit|NSMonthCalendarUnit|NSWeekCalendarUnit|NSWeekdayCalendarUnit fromDate:curDate]; // Get necessary date components

// set last of month
[comps setMonth:[comps month]+1];
[comps setDay:0];
NSDate *tDateMonth = [calendar dateFromComponents:comps];
NSLog(@"%@", tDateMonth);

也应该工作.

Answer 2

// Adapted from running code in my app

NSDate *curDate = [NSDate date];
NSCalendar *currentCalendar = [NSCalendar currentCalendar];
NSRange daysRange = 
[currentCalendar 
 rangeOfUnit:NSDayCalendarUnit 
 inUnit:NSMonthCalendarUnit 
 forDate:curDate];

// daysRange.length will contain the number of the last day
// of the month containing curDate

NSLog(@"%i", daysRange.length);

Answer 3

把它放在一个类别中:

-(NSDate*)lastDayOfMonth
{
    NSInteger dayCount = [self numberOfDaysInMonthCount];

    NSDateComponents *comp = [[self calendar] components:
                              NSCalendarUnitYear |
                              NSCalendarUnitMonth |
                              NSCalendarUnitDay fromDate:self];

    [comp setDay:dayCount];

    return [[self calendar] dateFromComponents:comp];
}

-(NSInteger)numberOfDaysInMonthCount
{
    NSRange dayRange = [[self calendar] rangeOfUnit:NSCalendarUnitDay
                                             inUnit:NSCalendarUnitMonth
                                            forDate:self];

    return dayRange.length;
}

-(NSCalendar*)calendar
{
    NSCalendar *calendar = [[NSCalendar alloc] initWithCalendarIdentifier:NSGregorianCalendar];    
    [calendar setTimeZone:[NSTimeZone timeZoneWithName:TIMEZONE]];
    return calendar;
}

Answer 4

解决方法功能：

-(int)GetLastDayOfMonth:(NSDate *)date
{
    int last_day = 27;
    NSCalendar *cal=[[NSCalendar alloc] initWithCalendarIdentifier:NSGregorianCalendar];
    NSDateComponents *compsMonth = [cal components:NSWeekdayCalendarUnit | NSYearCalendarUnit | NSMonthCalendarUnit | NSDayCalendarUnit fromDate:date];
    [compsMonth setDay:last_day];
    int month = [compsMonth month]; 
    while(TRUE){
        [compsMonth setDay:last_day+1];
        NSDate *dateFuture = [cal dateFromComponents:compsMonth];
        NSDateComponents *futureComps = [cal components:NSWeekdayCalendarUnit | NSYearCalendarUnit | NSMonthCalendarUnit | NSDayCalendarUnit fromDate:dateFuture];
        if(month != [futureComps month]){
            return last_day;
        }
        last_day+=1;
    }
    return last_day;
}