there is a way to check if an NSDate is this week or is next week?
i know that today is:
[NSDate date]
and then how i can do?
Use NSDateComponents, something like this:
NSCalendar *gregorian = [[NSCalendar alloc]
initWithCalendarIdentifier:NSGregorianCalendar];
NSDate *today = [NSDate date];
NSDateComponents *todaysComponents =
[gregorian components:NSWeekCalendarUnit fromDate:date];
NSUInteger todaysWeek = [todaysComponents week];
NSDate *anotherDate = [NSDate date];
NSDateComponents *otherComponents =
[gregorian components:NSWeekCalendarUnit fromDate:anotherDate];
NSUInteger anotherWeek = [otherComponents week];
if(todaysWeek==anotherWeek){
NSLog(#"another date is this week");
}else if(todaysWeek+1==anotherWeek){
NSLog(#"another date is next week")
}
You can also use other components like month or year to be completely sure.
NOTE: Don't use timeIntervals. By using NSDateComponents you ignore the hour, minutes and seconds. I think you want that.
pass the 2 dates to this method:
- (BOOL) isSameWeekAsDate: (NSDate *) aDate andDate:(NSDate *) bDate
{
NSDateComponents *components1 = [[NSCalendar currentCalendar] components:(NSYearCalendarUnit| NSMonthCalendarUnit | NSDayCalendarUnit | NSWeekCalendarUnit | NSHourCalendarUnit | NSMinuteCalendarUnit | NSSecondCalendarUnit | NSWeekdayCalendarUnit | NSWeekdayOrdinalCalendarUnit) fromDate:aDate];
NSDateComponents *components2 = [[NSCalendar currentCalendar] components:(NSYearCalendarUnit| NSMonthCalendarUnit | NSDayCalendarUnit | NSWeekCalendarUnit | NSHourCalendarUnit | NSMinuteCalendarUnit | NSSecondCalendarUnit | NSWeekdayCalendarUnit | NSWeekdayOrdinalCalendarUnit) fromDate:bDate];
if ([components1 week] != [components2 week]) return NO;
//return (abs([self timeIntervalSinceDate:aDate]) < 604800); // ops, forgot to change "self" with parameter "bDate":
return (abs([bDate timeIntervalSinceDate:aDate]) < 604800);
}
EDIT:
call it with 2 dates of different years:
[components setDay:31];
[components setMonth:12];
[components setYear:2010];
NSCalendar *gregorian = [[NSCalendar alloc] initWithCalendarIdentifier:NSGregorianCalendar];
NSDate *date1 = [gregorian dateFromComponents:components];
// second date (SATURDAY -of the same week, other year...)
[components setDay:1];
[components setMonth:1];
[components setYear:2011];
NSDate *date2 = [gregorian dateFromComponents:components];
if ([self isSameWeekAsDate:date1 andDate:date2]) {
NSLog(#"Same Week!");
}else{
NSLog(#"OTHER WEEK!");
}
I'am adding my solution (implemented as an NSDate category), which doesn't use week, which is deprecated in iOS7, iOS8
- (NSDate *)firstDateOfWeek {
NSCalendar *calendar = [NSCalendar currentCalendar];
NSDate *startOfWeek;
[calendar rangeOfUnit:NSCalendarUnitWeekOfYear startDate:&startOfWeek interval:NULL forDate:self];
return startOfWeek;
}
- (BOOL)isSameWeekWithDate:(NSDate *)date {
if (ABS(self.timeIntervalSince1970 - date.timeIntervalSince1970) > (7 * 24 * 60 * 60)) {
return NO;
}
return ([[self firstDateOfWeek] timeIntervalSince1970] == [[date firstDateOfWeek] timeIntervalSince1970]);
}
- (BOOL)isThisWeek {
return [self isSameWeekWithDate:[NSDate new]];
}
NSCalendar *cal = [NSCalendar currentCalendar];
NSDateComponents *components = [cal components:NSWeekCalendarUnit fromDate:yourDate];
NSInteger week = [components week]; // here your have a Integer with the weeknr of yourDate
components = [cal components:NSWeekCalendarUnit fromDate:[NSDate date]];
weekToday = [components week]; // here your have a Integer with the weeknr of today
The rest you should be able to do.
It might get another brainwork when it comes to the last week in year.
Clear?
NOTE: this calculates the idea of "week" using a Sunday-Saturday concept of week.
To calculate the current day of the week use the following from here:
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];
The rest should be pretty trivial. Get the current date and the date from your NSDate. Find the start and end dates using the day and the date (if today is monday then date - 1 day is the first day of the week etc). Figure out which week the date is in.
For iOS 7 and above, you have to replace NSWeekCalendarUnit with NSCalendarUnitWeekOfYear
- (NSInteger)thisW:(NSDate *)date
{
NSCalendar *gregorian = [[NSCalendar alloc]
initWithCalendarIdentifier:NSGregorianCalendar];
NSDateComponents *todaysComponents = [gregorian components:NSCalendarUnitWeekOfYear fromDate:[NSDate date]];
NSUInteger todaysWeek = [todaysComponents weekOfYear];
NSDateComponents *otherComponents = [gregorian components:NSCalendarUnitWeekOfYear fromDate:date];
NSUInteger datesWeek = [otherComponents weekOfYear];
//NSLog(#"Date %#",date);
if(todaysWeek==datesWeek){
//NSLog(#"Date is in this week");
return 1;
}else if(todaysWeek+1==datesWeek){
//NSLog(#"Date is in next week");
return 2;
} else {
return 0;
}
}
Forget about date components, you have to tweak lots of things (check if it's the last week of the year, check if Sunday is the beginning of the week...) and is prone to errors and spaghetti code.
This solves your issue and is extended to detect "last week", "previous weeks", "this week", "next week" and "later weeks"
-(EventWeekRange)numberOfWeeksFromTodayToEvent:(NSDate *)eventDate {
NSCalendar *calendar = [NSCalendar currentCalendar];
NSComparisonResult comparison = [calendar compareDate:[NSDate date] toDate:eventDate toUnitGranularity:NSCalendarUnitWeekOfYear];
if (comparison == NSOrderedSame) {
return RangeThisWeek;
} else if (comparison == NSOrderedAscending) { // The event date is in the future
// Advance today's date one week to check if this new date is in the same week as the event
NSDate *todaysNextWeek = [[NSDate date]dateByAddingTimeInterval:60*60*24*7];
if ([calendar compareDate:todaysNextWeek toDate:eventDate toUnitGranularity:NSCalendarUnitWeekOfYear] == NSOrderedSame) {
return RangeNextWeek;
} else {
return RangeLater;
}
} else { // The event date is in the past
// Advance the event's date one week to check if this new date is in the same week as today
NSDate *eventsNextWeek = [eventDate dateByAddingTimeInterval:60*60*24*7];
if ([calendar compareDate:eventsNextWeek toDate:[NSDate date] toUnitGranularity:NSCalendarUnitWeekOfYear] == NSOrderedSame) {
return RangeLastWeek;
} else {
return RangeEarlier;
}
}
}
Related
I have start date and a duration (period). For example startDate = '2014-02-12' period = 2. I desired dates 2014-02-12, 2014-02-14, 2014-02-16, .... I need to determine the current date is flagged during.
To check if the difference between the start date and the current date is an even
number of days, use NSDateComponents:
NSDate *startDate = ...;
NSDate *currentDate = [NSDate date];
NSCalendar *cal = [NSCalendar currentCalendar];
NSDateComponents *diff = [cal components:NSDayCalendarUnit fromDate:startDate
toDate:currentDate options:0];
NSInteger days = diff.day;
if (days % 2 == 0) {
// even number of days between start date and current date
}
You can get the desired dates using
- (id)dateByAddingTimeInterval:(NSTimeInterval)seconds
with seconds = period*3600*24
Calc the days from startDate to givenData, check the result whether it can be divisible by the period.
+ (NSInteger)daysWithinEraFromDate:(NSDate *)startDate toDate:(NSDate *)endDate {
NSCalendar *gregorian = [[NSCalendar alloc]
initWithCalendarIdentifier:NSGregorianCalendar];
[gregorian setTimeZone:[NSTimeZone localTimeZone]];
// for timezone issue
NSDate *newDate1 = [startDate dateByAddingTimeInterval:[[NSTimeZone localTimeZone] secondsFromGMT]];
NSDate *newDate2 = [endDate dateByAddingTimeInterval:[[NSTimeZone localTimeZone] secondsFromGMT]];
NSInteger startDay = [gregorian ordinalityOfUnit:NSDayCalendarUnit
inUnit: NSEraCalendarUnit forDate:newDate1];
NSInteger endDay = [gregorian ordinalityOfUnit:NSDayCalendarUnit
inUnit: NSEraCalendarUnit forDate:newDate2];
return endDay - startDay;
}
I've been struggling with my function to return todays date, at as close to zero seconds, minutes and hours as possible. So I'm able to re-use the same date with various transactions.
However, I've now discovered that my function returns yesterdays date?
+ (NSDate *)makeAbsoluteNSDate:(NSDate*)datSource {
NSCalendar *calendar = [[NSCalendar alloc] initWithCalendarIdentifier:
NSGregorianCalendar];
[calendar setTimeZone:[NSTimeZone localTimeZone]];
NSDateComponents *dateComponents = [calendar components:NSYearCalendarUnit |
NSMonthCalendarUnit | NSDayCalendarUnit
fromDate:datSource];
[dateComponents setHour:0];
[dateComponents setMinute:0];
[dateComponents setSecond:0];
NSDate *today = [calendar dateFromComponents:dateComponents];
[calendar release];
return today;
}
If you're trying to get today's or yesterday's midnight in your time zone, you should get NSDate that points to adequate time in GMT. In my case -2 hours as my timezone is +0200, so for midnight of 2011-08-26 I'll get 2011-08-25 22:00.
You have to make sure that you're setting the right timezone for the NSCalendar, which is [NSTimeZone systemTimeZone].
My routine for getting the midnight in my time zone is:
+ (NSDate *)midnightOfDate:(NSDate *)date {
NSCalendar *cal = [NSCalendar currentCalendar];
[cal setTimeZone:[NSTimeZone systemTimeZone]];
NSDateComponents *components = [cal components:NSYearCalendarUnit | NSMonthCalendarUnit | NSDayCalendarUnit fromDate:date];
[components setTimeZone:[cal timeZone]];
[components setHour:0];
[components setMinute:0];
[components setSecond:0];
return [cal dateFromComponents:components];
}
So, after a long discussion in comments, here's a midday function:
+ (NSDate *)middayOfDate:(NSDate *)date {
NSCalendar *cal = [NSCalendar currentCalendar];
[cal setTimeZone:[NSTimeZone systemTimeZone]];
NSDateComponents *components = [cal components:NSYearCalendarUnit | NSMonthCalendarUnit | NSDayCalendarUnit fromDate:date];
[components setTimeZone:[cal timeZone]];
[components setHour:12];
[components setMinute:0];
[components setSecond:0];
return [cal dateFromComponents:components];
}
Use below function to get date for yesterday :
- (NSDate *)getDate:(NSDate *)date days:(NSInteger)days hours:(NSInteger)hours mins:(NSInteger)mins seconds:(NSInteger)seconds
{
NSCalendar *cal = [NSCalendar currentCalendar];
NSDateComponents *components = [cal components:( NSHourCalendarUnit | NSMinuteCalendarUnit | NSSecondCalendarUnit ) fromDate:[[NSDate alloc] init]];
days = (days*24) + hours;
[components setHour:days];
[components setMinute:mins];
[components setSecond:seconds];
NSDate *returnDate = [cal dateByAddingComponents:components toDate:date options:0];
return returnDate;
}
To get yesterday date pass date = [NSDate date], day = -1, hours = 0 and mins = 0 as parameters in method calling.
All you need is [NSDate date] for the current date & time.
Here's a puzzler. I use the following to calculate the number of days between today's date and an upcoming birthday:
-(int) daysTillBirthday: (NSDate*)aDate {
// check to see if valid date was passed in
//NSLog(#"aDate passed in is %#",aDate);
if (aDate == nil) {
//NSLog(#"aDate is NULL");
return -1; // return a negative so won't be picked in table
}
//** HOW MANY DAYS TO BDAY
NSDate *birthDay = aDate; // [calendar dateFromComponents:myBirthDay];
//NSLog(#"birthDay: %#, today: %#",birthDay, [NSDate date]);
NSCalendar *calendar = [[[NSCalendar alloc] initWithCalendarIdentifier:NSGregorianCalendar] autorelease];
NSDateComponents *thisYearComponents = [calendar components:NSYearCalendarUnit fromDate:[NSDate date]];
NSDateComponents *birthDayComponents = [calendar components:NSMonthCalendarUnit|NSDayCalendarUnit fromDate:birthDay];
[birthDayComponents setYear:[thisYearComponents year]];
NSDate *birthDayThisYear = [calendar dateFromComponents:birthDayComponents];
//NSLog(#"birthDayThisYear: %#",birthDayThisYear);
NSDateComponents *differenceHours = [calendar components:NSHourCalendarUnit fromDate:[NSDate date] toDate:birthDayThisYear options:0];
NSDateComponents *differenceDays = [calendar components:NSDayCalendarUnit fromDate:[NSDate date] toDate:birthDayThisYear options:0];
// NSLog(#"difference days: %i, hours %i",[differenceDays day],[differenceHours hour]);
//*** I added this to try and correct the "error" ***
if ([differenceDays day] == 0) { // is it today, or tomorrow?
if (([differenceHours hour] <= 0) && ([differenceHours hour] >= -24)) { // must be today
//NSLog(#"TODAY");
return (0);
[calendar release];
}else if (([differenceHours hour] >= 0) && ([differenceHours hour] <= 24)) {
//NSLog(#"TOMORROW");
return (1);
[calendar release];
}
}
if ([differenceDays day] < 0) {
// this years birthday is already over. calculate distance to next years birthday
[birthDayComponents setYear:[thisYearComponents year]+1];
birthDayThisYear = [calendar dateFromComponents:birthDayComponents];
differenceDays = [calendar components:NSDayCalendarUnit fromDate:[NSDate date] toDate:birthDayThisYear options:0];
}
return ([differenceDays day]);
[calendar release];
}
Everything works, but the results are not accurate! I often find that birthdays that are close to today, but one day apart, result in [differenceDays day] being the same! i.e. if today is 6/6/2011 and I have two birthdays, one on 6/7/2011 and another 6/8/2011, then they are both shown as 1 day away!
Anyone have any better methods for accurately calculating this, or can spot the problem?
Many thanks.
NSCalendar provides a much easier way to do this:
NSDate *birthday = ...; // the birthday
NSDate *today = [NSDate date];
NSCalendar *c = [NSCalendar currentCalendar];
NSInteger birthdayDayOfYear = [c ordinalityOfUnit:NSDayCalendarUnit inUnit:NSYearCalendarUnit forDate:birthday];
NSInteger todayDayOfYear = [c ordinalityOfUnit:NSDayCalendarUnit inUnit:NSYearCalendarUnit forDate:today];
NSInteger different = birthdayDayOfYear - todayDayOfYear;
Basically, we're figuring out how far into the year today and the target date are (ie, today [5 Jun] is the 156th day of the year), and then subtract them to figure out how many days are in between them.
This method, of course, relies on the assumption that the target date is in the same year as the current date. I think it'd be fairly easy to work around that, however.
Another, even easier way to do this that will account for multi-year differences is like this:
NSDateComponents *d = [[NSCalendar currentCalendar] components:NSDayCalendarUnit fromDate:today toDate:birthday options:0];
NSInteger difference = [d day];
If you need to make sure that the birthday is in the future, that's easily accomplished as well:
NSDateComponents *year = [[[NSDateComponents alloc] init] autorelease];
NSInteger yearDiff = 1;
NSDate *newBirthday = birthday;
while([newBirthday earlierDate:today] == newBirthday) {
[year setYear:yearDiff++];
newBirthday = [[NSCalendar currentCalendar] dateByAddingComponents:year toDate:birthday options:0];
}
//continue on with the 2-line calculation above, using "newBirthday" instead.
update I updated the loop above to always increment from the original date n years at a time, instead of year-by-year. If someone is born on 29 Feb, incrementing by one year would yield 1 Mar, which would be wrong once you got to a leap year again. By jumping from the original date each time, we don't have this issue.
I do the exact same thing in one of my apps. Here is how I do it:
//This is the date your going to - in your case the birthday - note the format
NSString *myDateAsAStringValue = #"20110605";
// Convert string to date object
NSDateFormatter *dateFormat = [[NSDateFormatter alloc] init];
[dateFormat setDateFormat:#"yyyyMMdd"];
NSDate *newDate = [dateFormat dateFromString:myDateAsAStringValue];
NSDateComponents *dateComp = [[NSDateComponents alloc] init];
NSCalendar *Calander = [[NSCalendar alloc] initWithCalendarIdentifier:NSGregorianCalendar];
NSDateComponents *comps=[[NSDateComponents alloc] init];
unsigned int unitFlags = NSDayCalendarUnit | NSMonthCalendarUnit | NSYearCalendarUnit | NSHourCalendarUnit | NSMinuteCalendarUnit | NSSecondCalendarUnit;
dateComp = [Calander components:unitFlags fromDate:[NSDate date]];
[dateFormat setDateFormat:#"dd"];
[comps setDay:[[dateFormat stringFromDate:[NSDate date]] intValue]];
[dateFormat setDateFormat:#"MM"];
[comps setMonth:[[dateFormat stringFromDate:[NSDate date]] intValue]];
[dateFormat setDateFormat:#"yyyy"];
[comps setYear:[[dateFormat stringFromDate:[NSDate date]] intValue]];
[dateFormat setDateFormat:#"HH"];
[comps setHour:05];
[dateFormat setDateFormat:#"mm"];
[comps setMinute:30];
NSDate *currentDate=[Calander dateFromComponents:comps];
dateComp = [Calander components:unitFlags fromDate:newDate];
[dateFormat setDateFormat:#"dd"];
[comps setDay:[[dateFormat stringFromDate:newDate] intValue]];
[dateFormat setDateFormat:#"MM"];
[comps setMonth:[[dateFormat stringFromDate:newDate] intValue]];
[dateFormat setDateFormat:#"yyyy"];
[comps setYear:[[dateFormat stringFromDate:newDate] intValue]];
[dateFormat setDateFormat:#"HH"];
[comps setHour:05];
[dateFormat setDateFormat:#"mm"];
[comps setMinute:30];
NSDate *reminderDate=[Calander dateFromComponents:comps];
NSTimeInterval ti = [reminderDate timeIntervalSinceDate:currentDate];
int days = ti/86400;
return days;
I think I have found a solution. Checking the output carefully, it appears to all come down to the difference in HOURS. For example: comparing today with tomorrow's date might end up being, say, 18 hours away. This results in [difference day] being set at 0 i.e. it thinks tomorrow is today because it is less than 24 hours away.
You can see the fix below. I take the number of hours e.g. 18 and divide by 24 (to get the number of days). In this case 18/24 = 0.75. I then round this up i.e. to "1." So while [difference days] thinks tomorrow is today, by rounding up the hours, you know it is in fact tomorrow.
-(int) daysTillBirthday: (NSDate*)aDate {
// check to see if valid date was passed in
//NSLog(#"aDate passed in is %#",aDate);
if (aDate == nil) {
//NSLog(#"aDate is NULL");
return -1; // return a negative so won't be picked in table
}
//** HOW MANY DAYS TO BDAY
NSDate *birthDay = aDate; // [calendar dateFromComponents:myBirthDay];
NSCalendar *calendar = [[[NSCalendar alloc] initWithCalendarIdentifier:NSGregorianCalendar] autorelease];
NSDateComponents *thisYearComponents = [calendar components:NSYearCalendarUnit | NSHourCalendarUnit | NSMinuteCalendarUnit fromDate:[NSDate date]];
NSDateComponents *birthDayComponents = [calendar components:NSMonthCalendarUnit|NSDayCalendarUnit fromDate:birthDay];
NSInteger timeNow = [thisYearComponents hour];
[birthDayComponents setYear:[thisYearComponents year]];
[birthDayComponents setHour:timeNow];
NSDate *birthDayThisYear = [calendar dateFromComponents:birthDayComponents];
//NSLog(#"today %#, birthday %#",[NSDate date],birthDayThisYear);
NSDateComponents *difference = [calendar components:NSDayCalendarUnit fromDate:[NSDate date] toDate:birthDayThisYear options:0];
NSDateComponents *differenceHours = [calendar components:NSHourCalendarUnit fromDate:[NSDate date] toDate:birthDayThisYear options:0];
double daysFromHours = ((double)[differenceHours hour])/24; // calculate number of days from hours (and round up)
int roundedDaysFromHours = ceil(daysFromHours);
NSLog(#"daysFromHours %.02f, roundedDaysFromHours %i",daysFromHours,roundedDaysFromHours);
if ([difference day] < 0) {
// this years birthday is already over. calculate distance to next years birthday
[birthDayComponents setYear:[thisYearComponents year]+1];
birthDayThisYear = [calendar dateFromComponents:birthDayComponents];
difference = [calendar components:NSDayCalendarUnit fromDate:[NSDate date] toDate:birthDayThisYear options:0];
}
//NSLog(#"%i days until birthday", [difference day]);
return (roundedDaysFromHours);
[calendar release];
}
Hallo,
I am working on a Core Data app and have to do some filtering based on dates. I've run some testing and it appears that when comparing NSDates, Core Data is comparing the time component of the dates as well.
My code:
- (BOOL)hasSpeakersWithinDateRangeFrom:(NSDate *)startOfRange through:(NSDate *)endOfRange {
NSPredicate* dateRangePredicate = [NSPredicate predicateWithFormat:#"startOn <= %# && endOn >= %#", startOfRange, endOfRange];
NSSet* speakersWithinDateRange = [self.speakers filteredSetUsingPredicate:dateRangePredicate];
if ([speakersWithinDateRange count] > 0)
return YES;
else
return NO;
}
and I have a "convenience" method that is a one-line'er:
- (BOOL)hasSpeakersNow {
return [self hasSpeakersWithinDateRangeFrom:[NSDate date] through:[NSDate date]];
}
When I run some basic testing, it doesn't work as planned, and from what I can tell Core Data is comparing the time components of the NSDate objects along with the dates.
So, how can I rewrite the above to ignore time and only be sensitive to the day passed?
Thank you
You might want to get familiar with NSDateComponents and NSCalendar. What you will probably need to do is extract the components from your date and construct new NSDates using only the day, month, and year components without time components.
For the "current" day, you'll want to create a 1 day range by using today's date at midnight, and the date by adding 1 day to that. NSCalendar has methods to do some of this for you.
These docs might help:
NSCalendar Class Reference
NSDateComponents Class Reference
Date and Time Programming Guide
This is essentially the same as vikingosegundo, but both functions use the same method, and I personally prefer it for my use.
- (NSDate *)dateByMovingToBeginningOfDay
{
unsigned int flags = NSYearCalendarUnit | NSMonthCalendarUnit | NSDayCalendarUnit | NSHourCalendarUnit | NSMinuteCalendarUnit | NSSecondCalendarUnit;
NSDateComponents* parts = [[NSCalendar currentCalendar] components:flags fromDate:self];
[parts setHour:0];
[parts setMinute:0];
[parts setSecond:0];
return [[NSCalendar currentCalendar] dateFromComponents:parts];
}
- (NSDate *)dateByMovingToEndOfDay
{
unsigned int flags = NSYearCalendarUnit | NSMonthCalendarUnit | NSDayCalendarUnit | NSHourCalendarUnit | NSMinuteCalendarUnit | NSSecondCalendarUnit;
NSDateComponents* parts = [[NSCalendar currentCalendar] components:flags fromDate:self];
[parts setHour:23];
[parts setMinute:59];
[parts setSecond:59];
return [[NSCalendar currentCalendar] dateFromComponents:parts];
}
Set the startDate to time 0:00:00 and the endDate to 23:59:59
NSDate *startDate = [NSDate date]; //Now
startDate= [date dateAtMidnight]; //today at 0:00
NSDate *endDate = [NSDate date];
NSCalendar *cal = [[NSCalendar alloc] initWithCalendarIdentifier:#"gregorian"];
NSDateComponents *comps = [[NSDateComponents alloc] init];
[comps setDay:1];
[comps setSecond:-1]
endDate = [cal dateByAddingComponents:comps toDate:endDate options:0];//today 23:59:59
edit
this solution uses NSDate-Category NSDateAdditions.h, provided by Three20 (I wasnt aware it isn't defined in Cocoa)
- (NSDate*)dateAtMidnight {
NSDateFormatter* formatter = [[NSDateFormatter alloc] init];
formatter.dateFormat = #"yyyy-d-M";
NSString* formattedTime = [formatter stringFromDate:self];
NSDate* date = [formatter dateFromString:formattedTime];
[formatter release];
return date;
}
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