無法從日期獲得工作日

Question

我從coredata獲取日期，並嘗試獲取該日期的工作日。我嘗試了以下代碼，但無法正常工作。

    NSDateFormatter *weekDayFormatter = [[NSDateFormatter alloc]init];
    [weekDayFormatter setDateFormat:@"EEEE"];
    NSDate *weekDay = [results valueForKey:@"date"];
    NSLog(@"%@",weekDay);//This log is working.
    NSString *weekDayString = [weekDayFormatter stringFromDate:weekDay];
    NSLog(@"%@",weekDayString); //This log is displaying null.
    NSLog(@"%@ is spent on %@",[results valueForKey:@"amount"],weekDayString);

如果我使用的是[NSDate date]而不是[results valueForKey:@"date"] ，則它可以正常工作。

Answer 1

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

NSDateComponents *weekdayComponents =[gregorian components:NSWeekdayCalendarUnit fromDate:dateOfInterest];

NSInteger weekday = [weekdayComponents weekday];
// weekday 1 = Sunday for Gregorian calendar

[gregorian release];

Answer 2

嘗試使用NSCalendar從NSDate提取NSDateComponents 。

Answer 3

我認為[results valueForKey:@"date"]給出了NSString類型的對象。 檢查一次。 如果為true，則將其轉換為NSDate。

情況1：

 NSDateFormatter *weekDayFormatter = [[NSDateFormatter alloc]init];
    [weekDayFormatter setDateFormat:@"EEEE"];
    NSDate *weekDay = @"2013-03-13 11:06:55 +0000";//here warning is there...
    NSLog(@"%@",weekDay);//This log is working.
    NSString *weekDayString = [weekDayFormatter stringFromDate:weekDay];
    NSLog(@"%@",weekDayString); //It gives NULL...

在這種情況下，答案為空。

情況2：

NSDateFormatter *weekDayFormatter = [[NSDateFormatter alloc]init];
    [weekDayFormatter setDateFormat:@"EEEE"];
    NSDate *weekDay = [NSDate date];
    NSLog(@"%@",weekDay);//This log is working.
    NSString *weekDayString = [weekDayFormatter stringFromDate:weekDay];
    NSLog(@"%@",weekDayString); //It gives results...

在這種情況下，答案是yourResult。

Answer 4

您必須使用從[結果鍵值：@“日期”]中收到的日期格式。 之后，您嘗試根據需要格式化日期。

NSDateFormatter *weekDayFormatter = [[NSDateFormatter alloc]init];
[weekDayFormatter setDateFormat:SAME FORMAT YOU RECEIVING];
NSDate *weekDay = [weekDayFormatter dateFromString:[results valueForKey@"date"]];   
NSLog(@"%@",weekDay);
[weekDayFormatter setDateFormat:@"EEEE"];
NSString *weekDayString = [weekDayFormatter stringFromDate:weekDay];

Answer 5

// Your date as a string
NSString *yourDate = @"02-09-2011 20:54:18";    //  [results valueForKey:@"date"]

// Prepare an NSDateFormatter to convert to and from the string representation
NSDateFormatter *dateFormatter = [[NSDateFormatter alloc] init];

// set format as your Date string (Eg. dd/MM/yyyy for 25/12/2012)
[dateFormatter setDateFormat:@"dd-MM-yyyy HH:mm:ss"];

// Parse the string representation of the date
NSDate *date = [dateFormatter dateFromString:yourDate];

NSDateFormatter* theDateFormatter = [[NSDateFormatter alloc] init];
[theDateFormatter setFormatterBehavior:NSDateFormatterBehavior10_4];
[theDateFormatter setDateFormat:@"EEEE"];
NSString *weekDay =  [theDateFormatter stringFromDate:date];
NSLog(@"%@",weekDay);

Answer 6

NSDate *today = [NSDate date];

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

NSDateComponents *todayComponents = [gregorian components:NSWeekdayCalendarUnit fromDate:today];

NSLog(@"weekday = %d",[todayComponents weekday]);