I'm doing some weather app, in that i want to show the forecast for 4days i.e., current day to next 3days. I'm getting current day and the code is
NSCalendar* cal = [NSCalendar currentCalendar];
NSDateComponents* comp = [cal components:NSWeekdayCalendarUnit fromDate:[NSDate date]];
// 1 = Sunday, 2 = Monday, etc.
NSInteger day0 = comp.weekday;
NSLog(#"My DAY is %i", day0);
NSString *str;
NSMutableString *myString = [NSMutableString string];
str = [NSString stringWithFormat:#"%d",day0]; //%d or %i both is ok.
[myString appendString:str];
NSLog(#"My DAY is %#", myString);
And the output is 6 ie., Friday .... thats cool
How can i get the next day without incrementing the current day... I tried to increment the current day, but the problem is, if i get the current day as 7, it is incrementing to 8 no such thing in weedays right.. I'm newbie to xcode.. Help me out guys....
try the following:
NSDateComponents *dayComponent = [NSDateComponents new];
dayComponent.day = 1;
today = [calendar dateByAddingComponents:dayComponent toDate:today options:0];
"How can i get the next day without incrementing the current day..."
If you want a NSDate object representing each day, you can use NSDateComponents to add up:
NSDate *today = [NSDate date];
NSDateComponents *offset = [[NSDateComponents alloc] init];
offset.day = 1; // create a one day offset
NSDate *tomorrow = [[NSCalendar currentCalendar] dateByAddingComponents:offset toDate:today options:0];
Then get your weekday:
[[NSCalendar currentCalendar] components: NSWeekdayCalendarUnit fromDate:tomorrow];
"I tried to increment the current day, but the problem is, if i get the current day as 7, it is incrementing to 8 no such thing in weedays right.."
If it is enough to just increase the weekday of today, use a simple modulo (that's just basic in any programming language):
int weekdayOfTomorrow = (++weekdayOfToday % 7) + 1;
Related
This is my code and it perfectly returns number of days and months between two dates. i want to validate this like the difference between two dates should be exactly one year.like if u select july 29 2013 as start date and july 30 2014 as end date it should not be allowed to execute more.please help thanks in advance.
NSString *sta = txtStartdate.text; // This is the start date
NSString *en = txtEnddate.text; //this is end date
NSDateFormatter *f = [[NSDateFormatter alloc] init];
[f setDateFormat:#"dd/MM/yyyy"];
NSDate *startDat = [f dateFromString:sta];
NSDate *endDat = [f dateFromString:en];
[f release];
NSCalendar *gregorian = [[NSCalendar alloc]
initWithCalendarIdentifier:NSGregorianCalendar];
NSUInteger unitFlags = NSMonthCalendarUnit | NSDayCalendarUnit | NSYearCalendarUnit ;
NSDateComponents *components = [gregorian components:unitFlags
fromDate:startDat
toDate:endDat options:0];
NSInteger months = [components month];
NSInteger days = [components day];
NSInteger years = [components year];
NSLog(#"Number of months %d",months);
NSLog(#"Number of days %d",days);
NSLog(#"Number of years %d",years);
[gregorian release];
if(years < 1 )// This code works fine...i've edited it.. #wain helped
{
//
}
Add NSYearCalendarUnit to unitFlags, then when you have obtained the components you can request the year. This will deal with leap years better than you trying to count months and days or calculate the end date (unless you use the components to add a single year to the date to get the end date).
I need to make a calendar in which the user can scroll between several weeks. The first and last day of the week will be displayed like (e.g.) "June 4 - June 10".
Now I knew from the beginning that I'd need NSDate and NSCalendar, and indeed I managed to get the first and last day of just thist week, but it looks extremely cumbersome and I am sure there needs to be an easier method, as I need to get the dates for several more coming and past weeks.
This is my code which gives the day and month of the first and last day of the current week:
NSDate *today = [NSDate date];
NSCalendar* cal = [NSCalendar currentCalendar];
NSDateComponents* comp = [cal components:(NSWeekdayCalendarUnit|NSMonthCalendarUnit|NSWeekCalendarUnit|NSYearCalendarUnit|NSDayCalendarUnit|NSHourCalendarUnit) fromDate:[NSDate date]];
NSDate *beginOfWeek = [today dateByAddingTimeInterval: -1*([comp weekday]-2)*24*3600];
NSDate *endOfWeek = [today dateByAddingTimeInterval:(7-[comp weekday]+2)*24*3600];
NSLog(#"beginWeekDay=%d\n",[[cal components:(NSWeekdayCalendarUnit|NSMonthCalendarUnit|NSWeekCalendarUnit|NSDayCalendarUnit) fromDate: beginOfWeek] day]);
NSLog(#"endWeekDay=%d\n",[[cal components:(NSWeekdayCalendarUnit|NSMonthCalendarUnit|NSWeekCalendarUnit|NSDayCalendarUnit) fromDate: endOfWeek] day]);
NSLog(#"beginWeekmonth=%d\n",[[cal components:(NSWeekdayCalendarUnit|NSMonthCalendarUnit|NSWeekCalendarUnit|NSDayCalendarUnit) fromDate: beginOfWeek] month]);
NSLog(#"endWeekmonth=%d\n",[[cal components:(NSWeekdayCalendarUnit|NSMonthCalendarUnit|NSWeekCalendarUnit|NSDayCalendarUnit) fromDate: endOfWeek] month]);
I found this, which may be helpful to you: http://www.cocoanetics.com/2009/11/add-one-week-skip-weekend/
- (NSDate *)addWeekToDateAndSkipWeekend:(NSDate *)now {
int daysToAdd = 6; // we'll add the 7th later
// set up date components
NSDateComponents *components = [[[NSDateComponents alloc] init] autorelease];
[components setDay:daysToAdd];
// create a calendar
NSCalendar *gregorian = [[[NSCalendar alloc] initWithCalendarIdentifier:NSGregorianCalendar] autorelease];
NSDate *newDate = [gregorian dateByAddingComponents:components toDate:now options:0];
[components setDay:1]; // reuse to skip single days
NSDateComponents *newDateComps; // new componets to get weekday
// do always executed once, so we add the 7th day here
do
{
// add one day
newDate = [gregorian dateByAddingComponents:components toDate:newDate options:0];
newDateComps = [gregorian components:NSWeekdayCalendarUnit fromDate:newDate];
// repeat if the date is Saturday (7) or Sunday (1)
NSLog(#"weekday: %d", [newDateComps weekday]);
} while (([newDateComps weekday]==7)||([newDateComps weekday]==1));
return newDate;
}
Theoretically, you run this in a for loop with [NSDate date] and you will get the 7th day returned, you would then run the returned 7th day through this and get the next..etc..
May need minor alteration, to remove the check for Saturday+Sunday if you don't need it.
Hope this helps !
I have a class that holds an start date and an end date, normally initialised to the firt and last second of the month.
The following function works correctly going from Nov 2010 forwards into December and back again however going backwards from November ends up with startDate set to
2010-09-30 23:00:00 GMT
Ie. a month and an hour ago.
Strangely the endDate is still correctly set to
2010-11-01 00:00:00 GMT
And going forward a month from this incorrect date also results in the correct time and date.
Is this a bug or am I doing something I shouldn't be ?
-(void) moveMonth:(NSInteger)byAmount { // Positive or negative number of months
NSCalendar *cal = [NSCalendar currentCalendar];
NSDateComponents *components = [[[NSDateComponents alloc] init] autorelease];
// Update the start date
[components setMonth:byAmount];
NSDate *newStartDate = [cal dateByAddingComponents:components toDate:[self startDate] options:0];
[self setStartDate:newStartDate];
// And the end date
[components setMonth:1];
NSDate *newEndDate = [cal dateByAddingComponents:components toDate:[self startDate] options:0 ];
[self setEndDate:newEndDate];
}
SOLUTION: Answer correctly pointed out this is a DST issue
If you want to deal in absolute times and date then using the following avoids any DST being involved.
NSCalendar *cal = [[NSCalendar alloc ] initWithCalendarIdentifier:NSGregorianCalendar] autorelease];
NSTimeZone *zone = [NSTimeZone timeZoneWithName:#"GMT"];
[cal setTimeZone:zone];
It is probably not a bug but something related to DST changes in October-November period.
It would be easier to just grab the month and year of the current date, add/subtract the number of months difference, then generate a date from those new values. No need to worry about Daylight Saving changes, leap years, etc. Something like this ought to work:
-(void) moveMonth:(NSInteger)byAmount {
NSDate *now = [NSDate date];
NSCalendar *cal = [NSCalendar currentCalendar];
// we're just interested in the month and year components
NSDateComponents *nowComps = [cal components:(NSYearCalendarUnit|NSMonthCalendarUnit)
fromDate:now];
NSInteger month = [nowComps month];
NSInteger year = [nowComps year];
// now calculate the new month and year values
NSInteger newMonth = month + byAmount;
// deal with overflow/underflow
NSInteger newYear = year + newMonth / 12;
newMonth = newMonth % 12;
// month is 1-based, so if we've ended up with the 0th month,
// make it the 12th month of the previous year
if (newMonth == 0) {
newMonth = 12;
newYear = newYear - 1;
}
NSDateComponents *newStartDateComps = [[NSDateComponents alloc] init];
[newStartDateComps setYear: year];
[newStartDateComps setMonth: month];
[self setStartDate:[cal dateFromComponents:newDateComps]];
[newDateComps release];
// Calculate newEndDate in a similar fashion, calling setMinutes:59,
// setHour:23, setSeconds:59 on the NSDateComponents object if you
// want the last second of the day
}
Here is a way to do it properly. This method returns a new NSDate after adding/subtracting month "byAmount".
-(NSDate*) moveMonth:(NSInteger)byAmount {
NSDate *now = [NSDate date];
NSDateComponents *components = [[NSDateComponents alloc] init];
[components setMonth:byAmount];
NSDate *newDate = [[NSCalendar currentCalendar] dateByAddingComponents:components toDate:now options:0];
return newDate;
}
I'm writing a GTD app for the iPhone. For the due tasks, I want to display something like "Due tomorrow" or "Due yesterday" or "Due July 18th". Obviously, I need to display "Tomorrow" even if the task is less than 24 hours away (e.g. the user checks at 11pm on Saturday and sees there's a task on Sunday at 8am). So, I wrote a method to get the number of days in between two dates. Here's the code...
NSDateFormatter *dateFormatter = [[NSDateFormatter alloc] init];
[dateFormatter setDateFormat:#"yyyy-MM-dd-HH-mm"];
NSDate *nowDate = [dateFormatter dateFromString:#"2010-01-01-15-00"];
NSDate *dueDate = [dateFormatter dateFromString:#"2010-01-02-14-00"];
NSLog(#"NSDate *nowDate = %#", nowDate);
NSLog(#"NSDate *dueDate = %#", dueDate);
NSCalendar *calendar = [NSCalendar currentCalendar];
NSDateComponents *differenceComponents = [calendar components:(NSDayCalendarUnit)
fromDate:nowDate
toDate:dueDate
options:0];
NSLog(#"Days between dates: %d", [differenceComponents day]);
... and here's the output:
NSDate *nowDate = 2010-01-01 15:00:00 -0700
NSDate *dueDate = 2010-01-02 14:00:00 -0700
Days between dates: 0
As you can see, the method returns incorrect results. It should have returned 1 as the number of days between the two days. What am I doing wrong here?
EDIT: I wrote another method. I haven't done extensive unit tests, but so far it seems to work:
+ (NSInteger)daysFromDate:(NSDate *)fromDate inTimeZone:(NSTimeZone *)fromTimeZone untilDate:(NSDate *)toDate inTimeZone:(NSTimeZone *)toTimeZone {
NSCalendar *calendar = [NSCalendar currentCalendar];
unsigned unitFlags = NSYearCalendarUnit | NSMonthCalendarUnit | NSDayCalendarUnit | NSHourCalendarUnit | NSMinuteCalendarUnit | NSSecondCalendarUnit;
[calendar setTimeZone:fromTimeZone];
NSDateComponents *fromDateComponents = [calendar components:unitFlags fromDate:fromDate];
[calendar setTimeZone:toTimeZone];
NSDateComponents *toDateComponents = [calendar components:unitFlags fromDate:toDate];
[calendar setTimeZone:[NSTimeZone defaultTimeZone]];
NSDate *adjustedFromDate = [calendar dateFromComponents:fromDateComponents];
NSDate *adjustedToDate = [calendar dateFromComponents:toDateComponents];
NSTimeInterval timeIntervalBetweenDates = [adjustedToDate timeIntervalSinceDate:adjustedFromDate];
NSInteger daysBetweenDates = (NSInteger)(timeIntervalBetweenDates / (60.0 * 60.0 * 24.0));
NSDateComponents *midnightBeforeFromDateComponents = [[NSDateComponents alloc] init];
[midnightBeforeFromDateComponents setYear:[fromDateComponents year]];
[midnightBeforeFromDateComponents setMonth:[fromDateComponents month]];
[midnightBeforeFromDateComponents setDay:[fromDateComponents day]];
NSDate *midnightBeforeFromDate = [calendar dateFromComponents:midnightBeforeFromDateComponents];
[midnightBeforeFromDateComponents release];
NSDate *midnightAfterFromDate = [[NSDate alloc] initWithTimeInterval:(60.0 * 60.0 * 24.0)
sinceDate:midnightBeforeFromDate];
NSTimeInterval timeIntervalBetweenToDateAndMidnightBeforeFromDate = [adjustedToDate timeIntervalSinceDate:midnightBeforeFromDate];
NSTimeInterval timeIntervalBetweenToDateAndMidnightAfterFromDate = [adjustedToDate timeIntervalSinceDate:midnightAfterFromDate];
if (timeIntervalBetweenToDateAndMidnightBeforeFromDate < 0.0) {
// toDate is before the midnight before fromDate
timeIntervalBetweenToDateAndMidnightBeforeFromDate -= daysBetweenDates * 60.0 * 60.0 * 24.0;
if (timeIntervalBetweenToDateAndMidnightBeforeFromDate < 0.0)
daysBetweenDates -= 1;
}
else if (timeIntervalBetweenToDateAndMidnightAfterFromDate >= 0.0) {
// toDate is after the midnight after fromDate
timeIntervalBetweenToDateAndMidnightAfterFromDate -= daysBetweenDates * 60.0 * 60.0 * 24.0;
if (timeIntervalBetweenToDateAndMidnightAfterFromDate >= 0.0)
daysBetweenDates += 1;
}
[midnightAfterFromDate release];
return daysBetweenDates;
}
From the docs for components:fromDate:toDate:options::
The result is lossy if there is not a small enough unit requested to hold the full precision of the difference.
Since the difference is less than a full day, it correctly returns a result of 0 days.
If all you care about is tomorrow or yesterday vs. a specific date, then you can save yourself a lot of work and just test whether the dates are only one calendar day apart.
To do that, compare the dates to find which is earlier and which is later (and if they compare equal, bail out with that result), then test whether 1 day after the earlier date produces a date with the same year, month, and day-of-month as the later date.
If you really do want to know exactly how many calendar days there are from one date to the other:
Send the calendar a components:fromDate: message to get the year, month, and day-of-the-month of the first date.
Same as #1, but for the second date.
If the two dates are in the same year and month, subtract one day-of-month from the other and pass to abs (see abs(3)) to take the absolute value.
If they are not in the same year and month, test whether they are in adjacent months (e.g., December 2010 to January 2011, or June 2010 to July 2010). If they are, add the number of days in the earlier date's month (which you can obtain by sending the calendar a rangeOfUnit:inUnit:forDate: message, passing NSDayCalendarUnit and NSMonthCalendarUnit, respectively) to the day-of-month of the later date, then compare that result to the earlier date's day-of-month.
For example, when comparing 2010-12-31 to 2011-01-01, you would first determine that these are in adjacent months, then add 31 (number of days in 2010-12) to 1 (day-of-month of 2011-01-01), then subtract 31 (day-of-month of 2010-12-31) from that sum. Since the difference is 1, the earlier date is one day before the later date.
When comparing 2010-12-30 to 2011-01-02, you would determine that they are in adjacent months, then add 31 (days in 2010-12) to 2 (day-of-month of 2011-01-02), then subtract 30 (day-of-month of 2010-12-30) from that sum. 33 minus 30 is 3, so these dates are three calendar days apart.
Either way, I strongly suggest writing unit tests at least for this code. I've found that date-handling code is among the most likely to have subtle bugs that only manifest, say, twice a year.
One thing you might try is using rangeOfUnit: to zero out hours, minutes and seconds from the start and end dates.
NSCalendar *calendar = [NSCalendar currentCalendar];
NSCalendarUnit range = NSDayCalendarUnit;
NSDateComponents *comps = [[NSDateComponents alloc] init];
NSDate *start = [NSDate date];
NSDate *end;
[comps setDay:1];
[calendar rangeOfUnit:range startDate:&start interval:nil forDate:start];
end = [calendar dateByAddingComponents:comps toDate:start options:0];
In this example start will be 2010-06-19 00:00:00 -0400, end will be 2010-06-20 00:00:00 -0400. I'd imagine this would work better with NSCalendar's comparison methods, although I haven't tested it myself.
I am using this piece of code, it is working very well:
- (NSInteger)daysToDate:(NSDate*)date
{
if(date == nil) {
return NSNotFound;
}
NSUInteger otherDay = [[NSCalendar currentCalendar] ordinalityOfUnit:NSCalendarUnitDay inUnit:NSCalendarUnitEra forDate:date];
NSUInteger currentDay = [[NSCalendar currentCalendar] ordinalityOfUnit:NSCalendarUnitDay inUnit:NSCalendarUnitEra forDate:self];
return (otherDay-currentDay);
}
Here is the function I've used in the past
its defined in a category on NSDate
- (int) daysToDate:(NSDate*) endDate
{
//dates needed to be reset to represent only yyyy-mm-dd to get correct number of days between two days.
NSDateFormatter *temp = [[NSDateFormatter alloc] init];
[temp setDateFormat:#"yyyy-MM-dd"];
NSDate *stDt = [temp dateFromString:[temp stringFromDate:self]];
NSDate *endDt = [temp dateFromString:[temp stringFromDate:endDate]];
[temp release];
unsigned int unitFlags = NSMonthCalendarUnit | NSDayCalendarUnit;
NSCalendar *gregorian = [[NSCalendar alloc]
initWithCalendarIdentifier:NSGregorianCalendar];
NSDateComponents *comps = [gregorian components:unitFlags fromDate:stDt toDate:endDt options:0];
int days = [comps day];
[gregorian release];
return days;
}
-(NSInteger)daysBetweenTwoDates:(NSDate*)fromDateTime andDate:(NSDate*)toDateTime
{
NSDate *fromDate;
NSDate *toDate;
NSCalendar *calendar = [NSCalendar currentCalendar];
[calendar rangeOfUnit:NSDayCalendarUnit startDate:&fromDate
interval:NULL forDate:fromDateTime];
[calendar rangeOfUnit:NSDayCalendarUnit startDate:&toDate
interval:NULL forDate:toDateTime];
NSDateComponents *difference = [calendar components:NSDayCalendarUnit
fromDate:fromDate toDate:toDate options:0];
return [difference day];
}
Does anyone know if there is a way to set the first day of the week on a NSCalendar, or is there a calendar that already has Monday as the first day of the week, instead of Sunday.
I'm currently working on an app that is based around a week's worth of work, and it needs to start on Monday, not Sunday. I can most likely do some work to work around this, but there will be a lot of corner cases. I'd prefer the platform do it for me.
Thanks in advance
Here's some the code that I'm using. it's saturday now, so what I would hope is that weekday would be 6, instead of 7. that would mean that Sunday would be 7 instead of rolling over to 0
NSCalendar *gregorian = [[NSCalendar alloc] initWithCalendarIdentifier:NSGregorianCalendar];
[gregorian setFirstWeekday:0];
unsigned unitFlags = NSYearCalendarUnit | NSMonthCalendarUnit | NSDayCalendarUnit | NSWeekCalendarUnit | NSWeekdayCalendarUnit;
NSDateComponents *todaysDate = [gregorian components:unitFlags fromDate:[NSDate date]];
int dayOfWeek = todaysDate.weekday;
Edit: This does not check the edge case where the beginning of the week starts in the prior month. Some updated code to cover this: https://stackoverflow.com/a/14688780/308315
In case anyone is still paying attention to this, you need to use
ordinalityOfUnit:inUnit:forDate:
and set firstWeekday to 2. (1 == Sunday and 7 == Saturday)
Here's the code:
NSCalendar *gregorian = [[[NSCalendar alloc] initWithCalendarIdentifier:NSGregorianCalendar] autorelease];
[gregorian setFirstWeekday:2]; // Sunday == 1, Saturday == 7
NSUInteger adjustedWeekdayOrdinal = [gregorian ordinalityOfUnit:NSWeekdayCalendarUnit inUnit:NSWeekCalendarUnit forDate:[NSDate date]];
NSLog(#"Adjusted weekday ordinal: %d", adjustedWeekdayOrdinal);
Remember, the ordinals for weekdays start at 1 for the first day of the week, not zero.
Documentation link.
This code constructs a date that is set to Monday of the current week:
NSCalendar *gregorian = [[NSCalendar alloc] initWithCalendarIdentifier:NSGregorianCalendar];
NSDate *today = [NSDate date];
NSDate *beginningOfWeek = nil;
BOOL ok = [gregorian rangeOfUnit:NSWeekCalendarUnit startDate:&beginningOfWeek
interval:NULL forDate: today];
setFirstWeekday: on the NSCalendar object.
Sets the index of the first weekday for the receiver.
- (void)setFirstWeekday:(NSUInteger)weekday
Should do the trick.
In my opinion this settings should be dynamic according to the user locale.
Therefore one should use:
NSCalendar *gregorian = [[NSCalendar alloc] initWithCalendarIdentifier:NSGregorianCalendar];
[gregorian setLocale:[NSLocale currentLocale]];
This will cause the calendar to set the first week day according to the user locale automatically. Unless you are developing your app for a specific purpose/user locale (or prefer to allow the user to choose this day).
I've done it like this.
NSCalendar *gregorian = [[NSCalendar alloc] initWithCalendarIdentifier:NSGregorianCalendar];
NSDate *today = [NSDate date];
NSDateComponents *compForWeekday = [gregorian components:(NSWeekdayCalendarUnit) fromDate:today];
NSInteger weekDayAsNumber = [compForWeekday weekday]; // The week day as number but with sunday starting as 1
weekDayAsNumber = ((weekDayAsNumber + 5) % 7) + 1; // Transforming so that monday = 1 and sunday = 7
I had trouble with a lot of the answers here. . maybe it was just me. .
Here's an answer that works for me:
- (NSDate*)firstDayOfWeek
{
NSCalendar* cal = [[NSCalendar currentCalendar] copy];
[cal setFirstWeekday:2]; //Override locale to make week start on Monday
NSDate* startOfTheWeek;
NSTimeInterval interval;
[cal rangeOfUnit:NSWeekCalendarUnit startDate:&startOfTheWeek interval:&interval forDate:self];
return startOfTheWeek;
}
- (NSDate*)lastDayOfWeek
{
NSCalendar* cal = [[NSCalendar currentCalendar] copy];
[cal setFirstWeekday:2]; //Override locale to make week start on Monday
NSDate* startOfTheWeek;
NSTimeInterval interval;
[cal rangeOfUnit:NSWeekCalendarUnit startDate:&startOfTheWeek interval:&interval forDate:self];
return [startOfTheWeek dateByAddingTimeInterval:interval - 1];
}
Update:
As pointed out (elsewhere) by #vikingosegundo, in general its best to let the local determine which day is the start of the week, however in this case the OP was asking for the start of the week to occur on Monday, hence we copy the system calendar, and override the firstWeekDay.
The problem with Kris' answer is the edge case where the beginning of the week starts in the prior month. Here's some easier code and it also checks the edge case:
// Finds the date for the first day of the week
- (NSDate *)getFirstDayOfTheWeekFromDate:(NSDate *)givenDate
{
NSCalendar *calendar = [NSCalendar currentCalendar];
// Edge case where beginning of week starts in the prior month
NSDateComponents *edgeCase = [[NSDateComponents alloc] init];
[edgeCase setMonth:2];
[edgeCase setDay:1];
[edgeCase setYear:2013];
NSDate *edgeCaseDate = [calendar dateFromComponents:edgeCase];
NSDateComponents *components = [calendar components:NSYearCalendarUnit|NSMonthCalendarUnit|NSWeekCalendarUnit|NSWeekdayCalendarUnit fromDate:edgeCaseDate];
[components setWeekday:1]; // 1 == Sunday, 7 == Saturday
[components setWeek:[components week]];
NSLog(#"Edge case date is %# and beginning of that week is %#", edgeCaseDate , [calendar dateFromComponents:components]);
// Find Sunday for the given date
components = [calendar components:NSYearCalendarUnit|NSMonthCalendarUnit|NSWeekCalendarUnit|NSWeekdayCalendarUnit fromDate:givenDate];
[components setWeekday:1]; // 1 == Sunday, 7 == Saturday
[components setWeek:[components week]];
NSLog(#"Original date is %# and beginning of week is %#", givenDate , [calendar dateFromComponents:components]);
return [calendar dateFromComponents:components];
}
I see misunderstanding in the other messages. The first weekday, whichever it is, has number 1 not 0. By default Sunday=1 as in the "Introduction to Date and Time Programming Guide for Cocoa: Calendrical Calculations":
"The weekday value for Sunday in the Gregorian calendar is 1"
For the Monday as a first workday the only remedy I have is brute force condition to fix the calculation
NSCalendar *cal=[[NSCalendar alloc] initWithCalendarIdentifier:NSGregorianCalendar];
NSDateComponents *comps = [cal components:NSWeekdayCalendarUnit fromDate:[NSDate date]];
// set to 7 if it's Sunday otherwise decrease weekday number
NSInteger weekday=[comps weekday]==1?7:[comps weekday]-1;
Below also covers the edge case,
- (NSDate *)getFirstDayOfTheWeekFromDate:(NSDate *)givenDate
{
NSCalendar *calendar = [NSCalendar currentCalendar];
NSDateComponents *components = [calendar components:NSYearCalendarUnit|NSMonthCalendarUnit|NSWeekCalendarUnit|NSWeekdayCalendarUnit fromDate:givenDate];
[components setWeekday:2]; // 1 == Sunday, 7 == Saturday
if([[calendar dateFromComponents:components] compare: curDate] == NSOrderedDescending) // if start is later in time than end
{
[components setWeek:[components week]-1];
}
return [calendar dateFromComponents:components];
}
You can just change .firstWeekday of the calendar.
NSCalendar *calendar = [[NSCalendar alloc] initWithCalendarIdentifier:NSCalendarIdentifierGregorian];
calendar.firstWeekday = 2;
Then use rangeOfUnit:startDate:interval:forDate: to get the first day
NSDate *startOfWeek;
[calendar rangeOfUnit:NSCalendarUnitWeekOfYear startDate:&startOfWeek interval:nil forDate:[NSdate date]];
Try this:
NSCalendar *yourCal = [[NSCalendar alloc] initWithCalendarIdentifier:NSGregorianCalendar]
[yourCal setFirstWeekday:0];
Iv found out the way to display any weekday name using nscalender..using the following code..
Just open your console from xcode menu bar to see the results.Copy Paste the following code in your viewDidLoad method to get the first day of the week
NSDate *today = [NSDate date];
NSDateFormatter *dateFormat = [[NSDateFormatter alloc] init];
[dateFormat setDateFormat:#"MM/dd/yyyy :EEEE"];
NSString *dateString = [dateFormat stringFromDate:today];
NSLog(#"date: %#", dateString);
[dateFormat release];
NSCalendar *gregorian = [[NSCalendar alloc] initWithCalendarIdentifier:NSGregorianCalendar];
NSDateComponents *components = [gregorian components:NSWeekdayCalendarUnit | NSYearCalendarUnit | NSMonthCalendarUnit | NSDayCalendarUnit fromDate:today];
[components setDay:([components day]-([components weekday]-1))];
NSDate *beginningOfWeek = [gregorian dateFromComponents:components];
NSDateFormatter *dateFormat_first = [[NSDateFormatter alloc] init];
[dateFormat_first setDateFormat:#"MM/dd/yyyy :EEEE"];
NSString *dateString_first = [dateFormat_first stringFromDate:beginningOfWeek];
NSLog(#"First_date: %#", dateString_first);
The Output will be:
date: 02/11/2010 :Thursday
First_date: 02/07/2010 :Sunday
since i had run this program on 2/11/2010 u will get the desired output depending on the current date.
Similarly if u want to get the first working day of the week i.e Monday's date then just modify the code a bit:
CHANGE :[components setDay:([components day]-([components weekday]-1))];
TO
[components setDay:([components day]-([components weekday]-2))];
to get Mondays date for that week..
Similarly u can try to find the date of any of seven workdays by changing the integer -1,-2 and so on...
Hope u r question is answered..
Thanks,
Bonson Dias
The ISO 8601 calendar appears to have it's first weekday set to monday by default.
Using the Calendar nextWeekend (iOS 10 or later) and ordinality (thanks #kris-markel). I've gotten Monday as first of the week for the en_US calendar.
Here is an example of it with fallback to firstWeekday:
extension Calendar {
var firstWorkWeekday: Int {
guard #available(iOS 10.0, *) else{
return self.firstWeekday
}
guard let endOfWeekend = self.nextWeekend(startingAfter: Date())?.end else {
return self.firstWeekday
}
return self.ordinality(of: .weekday, in: .weekOfYear, for: endOfWeekend) ?? self.firstWeekday
}
}
The Swift solution (note, use .yearForWeekOfYear, not .year):
let now = Date()
let cal = Calendar.current
var weekComponents = cal.dateComponents([.yearForWeekOfYear, .weekOfYear,
.weekday], from: now)
//weekComponents.weekday = 1 // if your week starts on Sunday
weekComponents.weekday = 2 // if your week starts on Monday
cal.date(from: weekComponents) // returns date with first day of the week
… is there a calendar that already has Monday as the first day of the week, instead of Sunday.
Someday, there will be.
My simple way of doing this is to get Monday = 0, Sunday = 6:
NSDateComponents *dateComponents = [[NSCalendar currentCalendar] components:NSWeekdayCalendarUnit fromDate:[NSDate date]];
NSInteger dayNumStartingFromMonday = ([dateComponents weekday] - 2 + 7) % 7; //normal: Sunday is 1, Monday is 2