How to get the date a week in the past from today? - ios

I know how to get the date in iOS. I need to find last weeks date. So for example if today is 05/27/2011, I need to be able to get 05/20/2011
Thanks

This is crude but would work:
NSDate *prevWeekDate = [currentDate dateByAddingTimeInterval:(-60 * 60 * 24 * 7)];
Click for detail on dateByAddingTimeInterval:

How about:
NSCalendar * calendar = [NSCalendar currentCalendar];
NSDate * date = [NSDate date];
NSDateComponents *components = [[NSDateComponents alloc] init];
[components setWeek:-1];
NSDate * lastweek = [calendar dateByAddingComponents:components toDate:date options:0];
NSLog(#"%#", lastweek);
[components release];

Related

How to find Next Sunday in different Timezone (EST & IST)

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 convert NSDate into formate like days with hours?

i have one date like '2014-11-16T15:42:14' in server and now i want to convert this date into such formate like '1 day and 2 hours ago'.
can any body help me how can i solve this?
I wholeheartedly accept your down votes.(Please explain me the reason for you down vote such that i will not repeat my mistake).
Look at that example that will help you definately.
Copied From Here
NSCalendar *calendar = [NSCalendar currentCalendar];
NSDate *date = [NSDate date];
NSDateComponents *components = [[NSDateComponents alloc] init];
[components setWeekOfYear:1];
[components setHour:12];
NSLog(#"1 week and twelve hours from now: %#", [calendar dateByAddingComponents:components toDate:date options:0]);

Get weeks date in IOS SDK

I want to get the current & next week dates with day name.
i.e. If today's date is 28-06-2013 (Friday) then I want to get the dates from 23-06-2013(sunday) to 29-06-2013 (Saturday) as the this current week.
for next week
I want to get dates from 30-06-2013(sunday) to 06-07-2013 (saturday).
How can I do this?
Thank you,
Here is sample code that does the trick.
-(NSArray*)daysThisWeek
{
return [self daysInWeek:0 fromDate:[NSDate date]];
}
-(NSArray*)daysNextWeek
{
return [self daysInWeek:1 fromDate:[NSDate date]];
}
-(NSArray*)daysInWeek:(int)weekOffset fromDate:(NSDate*)date
{
NSCalendar *calendar = [NSCalendar currentCalendar];
//ask for current week
NSDateComponents *comps = [[NSDateComponents alloc] init];
comps=[calendar components:NSWeekCalendarUnit|NSYearCalendarUnit fromDate:date];
//create date on week start
NSDate* weekstart=[calendar dateFromComponents:comps];
if (weekOffset>0) {
NSDateComponents* moveWeeks=[[NSDateComponents alloc] init];
moveWeeks.week=1;
weekstart=[calendar dateByAddingComponents:moveWeeks toDate:weekstart options:0];
}
//add 7 days
NSMutableArray* week=[NSMutableArray arrayWithCapacity:7];
for (int i=1; i<=7; i++) {
NSDateComponents *compsToAdd = [[NSDateComponents alloc] init];
compsToAdd.day=i;
NSDate *nextDate = [calendar dateByAddingComponents:compsToAdd toDate:weekstart options:0];
[week addObject:nextDate];
}
return [NSArray arrayWithArray:week];
}
I was going to copy and paste an answer, but I'd suggest going and reading this post: Current Week Start and End Date. It looks like it'll help you achieve what you want to.
Something like this perhaps:
NSDate *now = [NSDate date];
NSCalendar *calendar = [NSCalendar currentCalendar];
NSInteger weekNumber = [[calendar components: NSWeekCalendarUnit fromDate:now] week];
NSCalendar *gregorian = [[NSCalendar alloc] initWithCalendarIdentifier:NSGregorianCalendar];
NSDateComponents *comp = [gregorian components:NSYearCalendarUnit fromDate:now];
[comp setWeek:weekNumber]; //Week number.
int i;
for (i = 1; i < 8; i=i+1){
[comp setWeekday:i]; //First day of the week. Change it to 7 to get the last date of the week
NSDate *resultDate = [gregorian dateFromComponents:comp];
NSDateFormatter *formatter = [[NSDateFormatter alloc] init];
[formatter setDateFormat:#"EEEE MMMM d, yyyy"];
NSString *myDateString = [formatter stringFromDate:resultDate];
NSLog(#"%#",myDateString);
}
Use NSDateComponents to find out the day of the week and then to find the date required before and after it.
Umm, I'm not an expert on this or anything, but a dumb way to do this is to first be able to recognize the day of the week from NSDate. Then you could add in if statements then the if statements could add and subtract the dates and nslog or printf each of them. Or I think there is a way by accessing the ios calendar.
okay so the above pretty much said and did more than what I said. Yeah go check the link on the post before me.
Use an NSCalendar instance to convert your start NSDate instance into an NSDateComponents instance, add 1 day to the NSDateComponents and use the NSCalendar to convert that back to an NSDate instance. Repeat the last two steps until you reach your end date.
NSDate *currentDate = [NSDate date];
NSCalendar *calendar = [[NSCalendar alloc] initWithCalendarIdentifier:NSGregorianCalendar];
NSDateComponents *comps = [[NSDateComponents alloc] init];
[comps setDay:1];
NSDate *nextDate = [calendar dateByAddingComponents:comps toDate:currentDate options:0];
Or else find start date and end date. like
NSDate *startDate = [NSDate date];
NSCalendar *calendar = [[NSCalendar alloc] initWithCalendarIdentifier:NSGregorianCalendar];
NSDateComponents *comps = [[NSDateComponents alloc] init];
[comps setDay:7];
NSDate *endDate = [calendar dateByAddingComponents:comps toDate:currentDate options:0];
then,
NSDate nextDate;
for ( nextDate = startDate ; [nextDate compare:endDate] < 0 ; nextDate = [nextDate addTimeInterval:24*60*60] ) {
// use date
}

ios set UIDatePicker time ahead

I grab the current time
NSDate * now = [[NSDate alloc] init];
NSCalendar *cal = [NSCalendar currentCalendar];
NSDateComponents * comps = [cal components:NSYearCalendarUnit|NSMonthCalendarUnit|NSDayCalendarUnit fromDate:now];
And I can set the DatePicker to any values I desire
NSDate * date = [cal dateFromComponents:comps];
[self.off setDate:date animated:TRUE];
But how do I add a, say, 5 minutes to "now"?
Try this
NSDate *date = [[NSDate date] dateByAddingTimeInterval:5*60];
Try
NSDate *now = [NSDate dateWithTimeInterval:300 sinceDate:[NSDate date]]

NSDate subtracting trouble

so in my app I want to subtract two dates. The first date is set date and the second one is the current date. So i tried this code:
NSString *setDateString = [NSString stringWithFormat:#"12:30"];
NSDateFormatter *dateFormatter = [[NSDateFormatter alloc] init];
NSDate *setDate = [dateFormatter dateFromString:setDateString];
NSTimeInterval interval = [[NSDate date] timeIntervalSinceDate:setDate];
But it counts the interval from 1970. But I need from the current day. Can anyone help?
I assume you want the difference between now and 1230 hrs of today. This can be done by
NSCalendar *gregorian = [[NSCalendar alloc] initWithCalendarIdentifier:NSGregorianCalendar];
NSDateComponents *components =[gregorian components:(NSDayCalendarUnit|NSYearCalendarUnit|NSMonthCalendarUnit) fromDate:today];
[components setHour:12];
[components setMinute:30];
[components setSecond:0];
NSDate *setDate=[gregorian dateFromComponents:components];
NSTimeInterval interval = [[NSDate date] timeIntervalSinceDate:setDate];
[gregorian release];
The reason it doesn't work for you is you've not given the format correctly. Alternatively, you can describe it correctly in setDateString by specifying all the components rather than just hour and minute.

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