获取iOS SDK中的周数

Question

我想从日期获得一年中的周数.我尝试了如下代码,但给了我一个错误的周数.

我的周代码:

NSDateFormatter *dateFormatter = [[NSDateFormatter alloc] init];
    [dateFormatter setDateFormat:@"YYYY-MM-dd"];
    NSDate *date = [dateFormatter dateFromString:@"2012-09-15"];


    NSCalendar *calendar = [NSCalendar currentCalendar];

    NSLog(@"week: %i", [[calendar components: NSWeekOfYearCalendarUnit fromDate:date] weekOfYear]); //Display 38 instead of 37
}

注意:如果我尝试使用[NSDate date]显示正确.

帮帮我解决这个问题..谢谢,

Answer 1

的ObjectiveC:

 NSCalendar *calendar = [NSCalendar currentCalendar];
 NSDateComponents *dateComponent = [calendar components:(NSWeekOfYearCalendarUnit | NSDayCalendarUnit | NSMonthCalendarUnit | NSYearCalendarUnit) fromDate:[NSDate date]];
 NSLog(@"%@",dateComponent);

迅速:

 NSCalendar *calendar = [NSCalendar currentCalendar];
    NSDateComponents *dateComponent = [calendar components:(NSCalendarUnitWeekOfYear | NSCalendarUnitDay | NSCalendarUnitMonth | NSCalendarUnitYear) fromDate:date];
    NSLog(@"%@",dateComponent);

斯威夫特3:

let calendar = NSCalendar.currentCalendar()
let dateComponent = calendar.components([.WeekOfYear, .Day, .Month, .Year], fromDate: NSDate(timeIntervalSinceNow: 0))
print("weekOfYear \(dateComponent.weekOfYear)")

Answer 2

[NSCalendar currentCalendar]默认情况下会为您提供阳历.您可以使用

NSCalendar *calendar = [[NSCalendar alloc] initWithCalendarIdentifier:NSISO8601Calendar];

获得符合ISO 08601标准的日历,其日期为第37周.