How to set the minimum date of an UIDatePicker to today + 5days with no Sunday included in the 5 days?
The code below first checks for the current weekday (Gregorian calendar => Sunday=1). If today is a day after Tuesday, then there will be a Sunday in today+5 days (see calculation of the offset).
After calculating the offset, it will be added to the current date.
NSCalendar *gregorian = [[NSCalendar alloc] initWithCalendarIdentifier:NSGregorianCalendar];
NSDate *currentDate = [NSDate date];
NSDateComponents *components = [gregorian components:NSWeekdayCalendarUnit fromDate:currentDate];
int offset = (components.weekday >= 3) ? 6 : 5;
NSDate *minDate = [gregorian dateByAddingUnit:NSDayCalendarUnit value:offset toDate:currentDate options:0];
//datePicker.minimumDate = minDate;
Related
+ (NSCalendar*)getGregorianCalendarInstance {
NSCalendar *calendar = [[NSCalendar alloc] initWithCalendarIdentifier:NSCalendarIdentifierGregorian];
return calendar;
}
+ (NSInteger)currentGregorianWeekOfYear:(NSDate*) date {
NSCalendar *gregorianCalendar = [self getGregorianCalendarInstance];
gregorianCalendar.firstWeekday = 2; // Monday = 2
NSDateComponents *components = [gregorianCalendar components:NSCalendarUnitWeekOfYear fromDate:date];
NSUInteger weekOfYear = [components weekOfYear];
return weekOfYear;
}
+ (NSInteger)currentGregorianYear:(NSDate*) date {
NSCalendar *gregorianCalendar = [self getGregorianCalendarInstance];
gregorianCalendar.firstWeekday = 2;
[gregorianCalendar setTimeZone:[NSTimeZone defaultTimeZone]];
gregorianCalendar.locale = [NSLocale localeWithLocaleIdentifier:#"en_US_POSIX"];
NSDateComponents *comps = [gregorianCalendar components: NSCalendarUnitYear fromDate:date];
NSInteger year = [comps year];
return year;
}
week number returns 52 instead of 1 in currentGregorianWeekOfYear function and year returns 2019 instead of 2020 in currentGregorianYear function for date = 2019-12-30 15:00:00 +0000
Specific reason to use the Gregorian calendar is to display 1st January in the 1st week of the year. With the ISO calendar, 1st January will be indicated as the 52nd or 53rd week of the year.
I already checked multiple references but it does not solve my problem:
WeekOfYear overflowing to 1 in 53rd week in gregorian calendar?
NSDateComponents weekOfYear returns wrong value
Swift: Gregorian Calendar and weeks/weekdays - inconsistent behavior
I have to find next Sunday date (NSDate) from device's current date.
I have used below logic:
NSCalendar *calendar = [[NSCalendar alloc] initWithCalendarIdentifier:NSCalendarIdentifierGregorian];
NSDateComponents *components = [calendar components:NSCalendarUnitWeekday | NSCalendarUnitYear | NSCalendarUnitMonth | NSCalendarUnitDay fromDate:self];
NSUInteger weekdayToday = [components weekday];
NSInteger daysToMonday = (8 - weekdayToday) % 7;
NSDate *weekEndPrev = [self dateByAddingTimeInterval:60*60*24*daysToMonday];
Here, in EST if time is near to 11 PM, I'm getting Monday as Weekend.
Let me know feasible solution. I have tried many options. Nothings works with 2 different timezones.
Thanks in Advance.
You need just to get the number of days you need and then just add them to your current date:
NSCalendar * calendar = [[NSCalendar alloc] initWithCalendarIdentifier:NSCalendarIdentifierGregorian];
NSDate * newDate = [calendar dateByAddingUnit:NSCalendarUnitDay value:value toDate:date options:0];
where value - is the number of days to add
Find current week Sunday Date first then add 7 days using NSDateComponents.
NSDate *today = [[NSDate alloc] init];
NSCalendar *gregorian = [[NSCalendar alloc] initWithCalendarIdentifier:NSCalendarIdentifierGregorian];
NSDateComponents *weekdayComponents = [gregorian components:NSCalendarUnitWeekday fromDate:today];
NSDateComponents *componentsToSubtract = [[NSDateComponents alloc] init];
[componentsToSubtract setDay:(0 - ([weekdayComponents weekday] - 1))];
NSDate *sudayCurWeek = [gregorian dateByAddingComponents:componentsToSubtract toDate:today options:0];
NSDateComponents *offsetComponents = [[NSDateComponents alloc] init];
[offsetComponents setDay:7];
NSDate *nextSunday = [gregorian dateByAddingComponents:offsetComponents toDate:sudayCurWeek options:0];
NSLog(#"%#",nextSunday);
You can do this without any math, which is best left to NSCalendar as it handles daylight savings etc. First you need a calendar with the correct time zone. For example for IST:
NSCalendar *gc = [NSCalendar calendarWithIdentifier:NSCalendarIdentifierGregorian];
gc.timeZone = [NSTimeZone timeZoneWithName:#"IST"];
Then you can use nextDateAfterDate:matchingUnit:value:options: to find the start of the next Sunday after a given time. For example:
NSDate *start = ... // the time you wish to start from
NSDate *nextSunday =
[gc nextDateAfterDate:start
matching:UnitNSCalendarUnitWeekday // match based on weekday number
value:1 // Sunday = weekday 1
options:NSCalendarMatchNextTime // read the docs!
];
The returned date, nextSunday, will be the next Sunday at 00:00 in the timezone of the calendar, gc.
HTH
Finally, I got solution..
NSDateComponents *components = [[NSCalendar currentCalendar] componentsInTimeZone:[NSTimeZone timeZoneWithAbbreviation:#"UTC"] fromDate:[NSDate date]]; // Pass date for which you want to find next Sunday
NSUInteger weekdayToday = [components weekday];
NSInteger daysToMonday = (8 - weekdayToday) % 7;
NSDate *weekEndPrev = [[NSDate date] dateByAddingTimeInterval:60*60*24*daysToMonday];
How to get the first day of a week for a date
this seems more easy at it is, since :
when the week starts with sunday, i need to get back the sunday date
if it starts on monday, i need to get the monday date
the input date is any date in week with time... i tried several approaches, but the edge case make it difficould
i made a function, which however doesn't work in 100% (not sure about the [components setDay: -weekday + 2];)
- (NSDate *)firstDateOfWeek {
NSCalendar * calendar = [NSCalendar currentCalendar];
NSDateComponents *weekdayComponents = [calendar components:(NSDayCalendarUnit | NSWeekdayCalendarUnit) fromDate:self];
// because sunday is 0, we need it to be 6
NSInteger weekday = (([weekdayComponents weekday] + 6) % 7);
NSDateComponents *components = [calendar components:(NSYearCalendarUnit | NSMonthCalendarUnit | NSDayCalendarUnit | NSWeekdayCalendarUnit) fromDate:self];
[components setDay: -weekday + 2];
return [calendar dateFromComponents:components];
}
It is easier to use the rangeOfUnit calendar method, which handles "start of the week" correctly according to the current locale:
NSDate *date = your date;
NSCalendar *calendar = [NSCalendar currentCalendar];
NSDate *startOfWeek;
[calendar rangeOfUnit:NSWeekOfYearCalendarUnit
startDate:&startOfWeek
interval:NULL
forDate:date];
Using NSDateComponents, it would work as follows (assuming that a week has 7 days):
NSDate *date = your date;
NSDateComponents *comp = [calendar components:NSYearCalendarUnit|NSMonthCalendarUnit|NSDayCalendarUnit|NSWeekdayCalendarUnit
fromDate:date];
NSDate *startOfDay = [calendar dateFromComponents:comp];
NSInteger diff = (NSInteger)[calendar firstWeekday] - (NSInteger)[comp weekday];
if (diff > 0)
diff -= 7;
NSDateComponents *subtract = [[NSDateComponents alloc] init];
[subtract setDay:diff];
NSDate *startOfWeek = [calendar dateByAddingComponents:subtract toDate:startOfDay options:0];
I've been looking for a way to format the following NSDate object:
19 Feb 2013
Like that
18-25 Feb 2013
The 19 occurs within the week between the 18th and the 25th of Feb.
I couldn't an easy method to do so, is there build in functionality in to the NSDateFormater? should I implement it myself?
I don't think there is built in functionality in NSDateFormatter to do this. However, Apple has an example of how to get the NSDate values for the first and last days of a the week given a date. Here's their example on getting the Sunday of the current week:
NSDate *today = [[NSDate alloc] init];
NSCalendar *gregorian = [[NSCalendar alloc]
initWithCalendarIdentifier:NSGregorianCalendar];
// Get the weekday component of the current date
NSDateComponents *weekdayComponents = [gregorian components:NSWeekdayCalendarUnit
fromDate:today];
/*
Create a date components to represent the number of days to subtract from the current date.
The weekday value for Sunday in the Gregorian calendar is 1, so subtract 1 from the number of days to subtract from the date in question. (If today is Sunday, subtract 0 days.)
*/
NSDateComponents *componentsToSubtract = [[NSDateComponents alloc] init];
[componentsToSubtract setDay: 0 - ([weekdayComponents weekday] - 1)];
NSDate *beginningOfWeek = [gregorian dateByAddingComponents:componentsToSubtract
toDate:today options:0];
/*
Optional step:
beginningOfWeek now has the same hour, minute, and second as the original date (today).
To normalize to midnight, extract the year, month, and day components and create a new date from those components.
*/
NSDateComponents *components =
[gregorian components:(NSYearCalendarUnit | NSMonthCalendarUnit |
NSDayCalendarUnit) fromDate: beginningOfWeek];
beginningOfWeek = [gregorian dateFromComponents:components];
Since Sunday is not the beginning of the week in all locales, they also show how to get the beginning of the week as defined by the calendar's locale:
NSDate *today = [[NSDate alloc] init];
NSDate *beginningOfWeek = nil;
BOOL ok = [gregorian rangeOfUnit:NSWeekCalendarUnit startDate:&beginningOfWeek
interval:NULL forDate: today];
e.g. 01.10.2010 is friday => 27.09.2010 is monday.
I have no idea how to manage this one. btw: how can I calculate with dates?
For time/date calculations use NSDateComponents.
Listing 2 Getting the Sunday in the current week
NSDate *today = [[NSDate alloc] init];
NSCalendar *gregorian = [[NSCalendar alloc] initWithCalendarIdentifier:NSGregorianCalendar];
// Get the weekday component of the current date
NSDateComponents *weekdayComponents = [gregorian components:NSWeekdayCalendarUnit fromDate:today];
/*
Create a date components to represent the number of days to subtract from the current date.
The weekday value for Sunday in the Gregorian calendar is 1, so subtract 1 from the number of days to subtract from the date in question. (If today's Sunday, subtract 0 days.)
*/
NSDateComponents *componentsToSubtract = [[NSDateComponents alloc] init];
[componentsToSubtract setDay: 0 - ([weekdayComponents weekday] - 1)];
NSDate *beginningOfWeek = [gregorian dateByAddingComponents:componentsToSubtract toDate:today options:0];
/*
Optional step:
beginningOfWeek now has the same hour, minute, and second as the original date (today).
To normalize to midnight, extract the year, month, and day components and create a new date from those components.
*/
NSDateComponents *components =
[gregorian components:(NSYearCalendarUnit | NSMonthCalendarUnit | NSDayCalendarUnit)
fromDate: beginningOfWeek];
beginningOfWeek = [gregorian dateFromComponents:components];
In later versions, there is a smarter way:
NSCalendar *cal = [NSCalendar currentCalendar];
[cal setFirstWeekday:2]; //2 is monday. 1:Sunday .. 7:Saturday don't set it, if user's locale should determine the start of a week
NSDate *now = [NSDate date];
NSDate *monday;
[cal rangeOfUnit:NSWeekCalendarUnit // we want to have the start of the week
startDate:&monday // we will write the date object to monday
interval:NULL // we don't care for the seconds a week has
forDate:now]; // we want the monday of today's week
If you actually change the weekday that represents the start of the week (Sunday vs. Monday), you should change it back after this snippet.