I am trying to get current date with adding device time zone but is show 1 hr late that original date. I thing , I am getting problem of DaylightSavingTime.
How to disable isDaylightSavingTime = FALSE .
here is the code, I have used..
NSDate *date = [NSDate Date];
NSTimeZone *currentTimeZon = [NSTimeZone localTimeZone];
if ([currentTimeZon isDaylightSavingTime])
{
NSLog(#"East coast is NOT on DT");
}
else
{
NSLog(#"East coast is on DT");
}
NSTimeInterval timeZoneOffset = [currentTimeZon secondsFromGMTForDate:currentDate];
NSTimeInterval gmtTimeInterval = [date timeIntervalSinceReferenceDate] - timeZoneOffset;
NSDate *gmtDate = [NSDate dateWithTimeIntervalSinceReferenceDate:gmtTimeInterval];
NSLog(#"### Announcement gmtDate = %#",gmtDate);
I am getting time with 1 Hour difference, date is perfact.
Use NSCalendar, it understands time zones, daylight savings, etc. As #albertamg says, NSDate is just the time since a reference at UTC (GMT), it has no other concept.
Related
I have a NSString (ex. "2011-04-12 19:23:39"), and what I did to format it to a NSDate was the following:
[inputFormatter setDateFormat:#"yyyy-MM-dd HH:mm:ss"];
NSDate *date = [inputFormatter dateFromString:newDateString];
but what it outputs when I nslog the date is this:
2011-04-12 23:23:39 +0000
which is about 4 hours off. Is there something I missed? Possibly a time zone problem?
The answer in short, is the Date is being returned GMT unless specified otherwise. You can set your timezone to get the correct date. If you plan on using the date in the app to set anything ( like localNotification time or Event ) you will need to do something special with the date because if you set the date in the iPhone it will be set as GMT time and will be off by a few hours. ( in your case 4 hours ). I do this exact thing I just described in one of my apps.
I made a mess of trying to get this to work correctly without having the hours be off. It was a huge PITA to figure out but its working now. I have copied, pasted, and edited my code to share. Again, its messy but it works! The pickerChanged is getting its info from a UIDatePicker
Using the code below. To answer your question, you can stop at "destinationDate". That will return to you the corrected time for your current time zone. I just provided the extra incase you were trying to use the date in the Phone somewhere.
NOTE: for a quick example i put the Event reminder in the same function as the datepicker, you will NOT want to do that otherwise you will have alot of reminders set everytime the wheel scrolls in the datepicker.
The code is below.
- (void)pickerChanged:(id)sender
{
NSLog(#"value: %#",[sender date]);
NSDate* date= [sender date];
NSDateFormatter *formatter=[[[NSDateFormatter alloc]init]autorelease];
[formatter setDateFormat:#"MM/dd/yyyy hh:mm:ss a"];
[formatter setTimeZone:[NSTimeZone systemTimeZone]];
[formatter setTimeStyle:NSDateFormatterLongStyle];
NSString *dateSelected =[formatter stringFromDate:date];
NSString *timeZone = [dateSelected substringFromIndex:12];
NSTimeZone* destinationTimeZone = [NSTimeZone systemTimeZone];
//here we have to get the time difference between GMT and the current users Date (its in seconds)
NSInteger destinationGMTOffset = [destinationTimeZone secondsFromGMTForDate:date];
//need to reverse offset so its correct when we put it in the calendar
correctedTimeForCalendarEvent = destinationGMTOffset + (2*(-1*destinationGMTOffset));
//date to enter into calendar (we will use the correctedTimeForCalendarEvent to correct the time otherwise it will be off by a few hours )
NSDate * destinationDate = [[[NSDate alloc] initWithTimeInterval:destinationGMTOffset sinceDate:date] autorelease];
NSDate * dateForReminder = destinationDate;
// return destinationDate;
NSLog(#"value: %# - %#",destinationDate,dateForReminder);
//DO NOT put this code in this same function this is for a quick example only on StackOverflow
//otherwise you will have reminders set everytime the users scrolled to a different time
//set event reminder
//make sure to import EventKit framework
EKEventStore *eventDB = [[[EKEventStore alloc] init]autorelease];
EKEvent *myEvent = [EKEvent eventWithEventStore:eventDB];
NSString * eventTitle = [NSString stringWithFormat:#"%# - %#",app.dealerBusinessName,serviceOrComments.text];
myEvent.title = eventTitle;
//double check date one more time
NSLog(#"value: %#",destinationDate);
//set event time frame (1 hour) the "initWithTimeInterval" is where we account for the users timezone by adding the correctedTime from GMT to the calendar time ( so its not off by hours when entering into calendar)
myEvent.startDate = [[[NSDate alloc] initWithTimeInterval:correctedTimeForCalendarEvent sinceDate:destinationDate ]autorelease];
myEvent.endDate = [[[NSDate alloc] initWithTimeInterval:3600 sinceDate:myEvent.startDate]autorelease];
myEvent.allDay = NO;
//set event reminders 1 day and 1 hour before
myAlarmsArray = [[[NSMutableArray alloc] init] autorelease];
EKAlarm *alarm1 = [EKAlarm alarmWithRelativeOffset:-3600]; // 1 Hour
EKAlarm *alarm2 = [EKAlarm alarmWithRelativeOffset:-86400]; // 1 Day
[myAlarmsArray addObject:alarm1];
[myAlarmsArray addObject:alarm2];
myEvent.alarms = myAlarmsArray;
[myEvent setCalendar:[eventDB defaultCalendarForNewEvents]];
NSError *err;
[eventDB saveEvent:myEvent span:EKSpanThisEvent error:&err];
if (err == noErr) {
//no error, but do not show alert because we do that below.
}
}
NSDateFormatter use the current device timezone when it created the NSDate object. NSDate stores the date/time in GMT. Therefore by default NSLog will output the date/time in GMT+0. So, there's nothing wrong with your code. Now if you want to output the NSDate to your current timezone, your will have to use a NSDateFormatter object.
Your data and date formatter omit the TimeZone specifier. So something like this:
[inputFormatter setDateFormat:#"yyyy-MM-dd HH:mm:ssZ"];
Would work - the Z is the timezone specifier and will parse both numeric offsets and timezone codes. Although in your case as your input date has no TimeZone information it won't work.
Your correct Time string should be like "2011-04-12 19:23:39 -0400" or "2011-04-12 19:23:39 EST "
Depending on where you get your date from, you should fix that to produce a fully qualified date if you can't do that, you will have to agree timezone offsets with the server or simply 'hard code' a timezone offset and add that number of seconds to your NSDate.
The date is being logged as a UTC date can be seen by the +0000 at the end. The date format you are using to parse the string assumes your local time zone which is presumably 4 hours behind UTC with daylight savings and the standard -5 hours.
Use -[NSDateFormatter setTimeZone:] to provide the date formatter with timezone information. You can use the local time zone, or if you have a fixed time zone associated with the date information, I recommend creating the timezone with the name (such as "America/East") rather than the abbreviation (such as "EST" or "EDT"), since the name does not force daylight savings into effect, but uses the correct daylight savings offset for that date in that timezone.
I am trying to find how many milliseconds into the current day we are. I can't find a method to return the time in milliseconds ignoring date, so I figured I could calculate it off of the value returned by timeIntervalSince 1970 method.
I did this:
NSLog(#"%f", [[NSDate date] timeIntervalSince1970]);
2013-05-21 16:29:09.453 TestApp[13951:c07] 1369171749.453490
Now my assumption is that, since there are 86,400 seconds in a day I could divide this value by 86400 and get how many days have elapsed since 1970. Doing this gives me 15846.8952483 days. Now, if my assumption holds, I am 89.52483% through the current day. So multiple 24 hours by 86.52659% would give me a current time of the 21.4859592 hour or about 09:29 PM. As you can see from my NSLog this is about 5 hours from the real time, but I believe the interval returned is GMT so this would be 5 hours ahead of my time zone.
So I figured, well what the heck, I'll just roll with it and see what happens.
I cut off the decimal places by doing:
float timeSince1970 = [[NSDate date] timeIntervalSince1970]/86400.0;
timeSince1970 = timeSince1970 - (int)timeSince1970
Then calculate the milliseconds that have taken place thus far today:
int timeNow = timeSince1970 * 86400000;
NSLog(#"%i", timeNow);
2013-05-21 16:33:37.793 TestApp[14009:c07] 77625000
Then I convert the milliseconds (which still seem appropriate) to NSDate:
NSString *timeString = [NSString stringWithFormat:#"%d", timeNow];
NSDateFormatter *dateFormatter = [[NSDateFormatter alloc]init];
[dateFormatter setDateFormat:#"A"]
NSDate *dateNow = [dateFormatter dateFromString:timeString];
NSLog(#"%#", dateNow);
2013-05-21 16:29:09.455 TestApp[13951:c07] 2000-01-02 03:29:00 +0000
And there is my problem. Rather than returning a 2000-01-01 date with some hours and minutes attached, it is returning a 2000-01-02 date. Why!?
EDIT
I got it working by "removing" the extra 5 hours I noted in the above with:
int timeNow = (timeSince1970 * 86400000) - (5 * 60 * 60 * 1000);
I don't understand why this is necessary though. If someone can explain I'd greatly appreciate it.
EDIT 2
Perhaps I should be asking a more elementary question about how to accomplish the task I'm trying to accomplish. I care about times (for example, 4pm is important but I could care less about the date). I've been storing these in NSDates created by:
[dateFormatter setDateFormat:#"hh:mm a"];
[dateFormatter dateFromString#"04:00 PM"];
All this seems to be going fine. Now I want to compare current time to my saved time and find out if it is NSOrderedAscending or NSOrderedDescending and respond accordingly. Is there a better way to be accomplishing this?
You need to use NSCalendar to generate NSDateComponents based on right now, then set the starting hour, minute, and second all to 0. That will give you the beginning of today. Then you can use NSDate's -timeIntervalSinceNow method to get back the time elapsed between now and your start date.
NSCalendar *cal = [NSCalendar currentCalendar];
NSDate *now = [NSDate date];
// BUILD UP NSDate OBJECT FOR THE BEGINNING OF TODAY
NSDateComponents *comps = [cal components: (NSYearCalendarUnit | NSMonthCalendarUnit | NSDayCalendarUnit) fromDate: now];
comps.hour = 0;
comps.minute = 0;
comps.second = 0;
// USE CALENDAR TO GENERATE NEW DATE FROM COMPONENTS
NSDate *startOfToday = [cal dateFromComponents: comps];
// YOUR ELAPSED TIME
NSLog(#"%f", [startOfToday timeIntervalSinceNow]);
Edit 1
If you're just looking to compare some NSDateObjects you can see if the time interval between then and now is negative. If so, that date is in the past.
NSDate *saveDate = [modelObject lastSaveDate];
NSTimeInterval difference = [saveDate timeIntervalSinceNow];
BOOL firstDateIsInPast = difference < 0;
if (firstDateIsInPast) {
NSLog(#"Save date is in the past");
}
You could also use compare:.
NSDate* then = [NSDate distantPast];
NSDate* now = [NSDate date];
[then compare: now]; // NSOrderedAscending
The part of your question that says that you want to calculate "how many milliseconds into the current day we are" and then "4pm is important but I could care less about the date" makes it not answerable.
This is because "today" there could have been a time change, which changes the number of milliseconds since midnight (by adding or subtracting an hour, for instance, or a leap second at the end of a year, etc....) and if you don't have the date, you can't determine the number of milliseconds accurately.
Now, to address your edited question: If we assume today's date, then you need to use the time that you have stored and combine it with today's date to get a "specific point in time" which you can compare to the current date and time:
NSString *storedTime = #"04:00 PM";
// Use your current calendar
NSCalendar *cal = [NSCalendar currentCalendar];
// Create a date from the stored time
NSDateFormatter *dateFormatter = [NSDateFormatter new];
[dateFormatter setDateFormat:#"hh:mm a"];
NSDate *storedDate = [dateFormatter dateFromString:storedTime];
// Break it up into its components (ie hours and minutes)
NSDateComponents *storedDateComps = [cal components:NSHourCalendarUnit | NSMinuteCalendarUnit
fromDate:storedDate];
// Now we get the current date/time:
NSDate *currentDateAndTime = [NSDate date];
// Break it up into its components (the date portions)
NSDateComponents *todayComps = [cal components:NSYearCalendarUnit | NSMonthCalendarUnit | NSDayCalendarUnit
fromDate:currentDateAndTime];
// Combine with your stored time
todayComps.hour = storedDateComps.hour;
todayComps.minute = storedDateComps.minute;
// Create a date from the comps.
// This will give us today's date, with the time that was stored
NSDate *currentDateWithStoredTime = [cal dateFromComponents:todayComps];
// Now, we have the current date and the stored value as a date, so it is simply a matter of comparing them:
NSComparisonResult result = [currentDateAndTime compare:currentDateWithStoredTime];
it is returning a 2000-01-02 date. Why!?
Because your dateFormatter uses the current system locale's timezone.
If you insert ...
dateFormatter.timeZone = [NSTimeZone timeZoneForSecondsFromGMT:0];
... your date formatter will interpret the string correctly. But why not creating the date directly:
NSDate *dateNow = [NSDate dateWithTimeIntervalSinceReferenceDate:timeNow];
This question already has an answer here:
sethours in NSDateComponents
(1 answer)
Closed 9 years ago.
I am trying to create a date with the time set to 12:00:01 am. Seconds and minutes set to their values correctly but the hour value always goes to whatever i set the value, + 4. Why 4? What is so special about that value? The minute and second values set to what I want correctly but it appears the hours value simply adds rather than replaces.
here is the code,
NSDate *now = [NSDate date];
NSCalendar *calendar = [[NSCalendar alloc] initWithCalendarIdentifier:NSGregorianCalendar];
NSDateComponents *components = [calendar components:NSYearCalendarUnit|NSMonthCalendarUnit|NSDayCalendarUnit fromDate:now];
[components setHour:0];
[components setMinute:0];
[components setSecond:1];
NSDate *compareTime = [calendar dateFromComponents:components];
NSLog(#"compareTime: %#", compareTime);
NSLog(#"currentTime: %#", now);
output is :
compareTime: 2013-05-17 04:00:01 +0000
currentTime: 2013-05-17 15:00:37 +0000
EST is 4 hours ahead of GMT, hence your offset. Here's some code we use to create dates plus and minus the current time in the local time zone.
- (NSDate *) getDateWithHoursOffset : (int) aHourInt
{
CFGregorianDate gregorianStartDate, gregorianEndDate;
CFGregorianUnits startUnits = { 0,0,0, aHourInt,0,0 }; //2 hours before
CFGregorianUnits endUnits = { 0,0,0, 8,0,0 }; //5 hours ahead
CFTimeZoneRef timeZone = CFTimeZoneCopySystem();
gregorianStartDate = CFAbsoluteTimeGetGregorianDate(CFAbsoluteTimeAddGregorianUnits(CFAbsoluteTimeGetCurrent(), timeZone, startUnits),timeZone);
gregorianStartDate.minute = 0;
gregorianStartDate.second = 0;
gregorianEndDate = CFAbsoluteTimeGetGregorianDate(CFAbsoluteTimeAddGregorianUnits(CFAbsoluteTimeGetCurrent(), timeZone, endUnits),timeZone);
gregorianEndDate.minute = 0;
gregorianEndDate.second = 0;
NSDate* startDate = [NSDate dateWithTimeIntervalSinceReferenceDate:CFGregorianDateGetAbsoluteTime(gregorianStartDate, timeZone)];
CFRelease(timeZone);
return startDate;
}
NSDates exist independently of timezones. If you need the date to display 12:00:01 in the application, you should use a NSDateFormatter.
NSDateFormatter *dateFormatter = [[NSDateFormatter alloc] init];
[dateFormatter setTimeStyle:NSDateFormatterFullStyle];
NSLog(#"formattedTime: %#", [dateFormatter stringFromDate:compareTime]);
This returns:
formattedTime: 12:00:01 AM Central Daylight Time
The problem is that your dates are correct but they're being logged in UTC relative to your device's time zone and that seems confusing. (It is, at first)
Your compare time is correct. It is set to midnight your time and outputted as UTC and if you're EST midnight would be 4am UTC:
compareTime: 2013-05-17 04:00:01 +0000
Current time is also correct, and again it is UTC time relative to your device's time zone:
currentTime: 2013-05-17 15:00:37 +0000
Your times are correct, its the output that is deceiving you.
This code (shamefully stolen from a thread listed below) should output compareTime's UTC date as 00:00:01 +0000. Though for date calculations UTC should be fine.
NSTimeZone* sourceTimeZone = [NSTimeZone timeZoneWithAbbreviation:#"GMT"];
NSTimeZone* destinationTimeZone = [NSTimeZone systemTimeZone];
NSInteger sourceGMTOffset = [sourceTimeZone secondsFromGMTForDate:sourceDate];
NSInteger destinationGMTOffset = [destinationTimeZone secondsFromGMTForDate:sourceDate];
NSTimeInterval interval = destinationGMTOffset - sourceGMTOffset;
NSDate* destinationDate = [[NSDate alloc] initWithTimeInterval:interval sinceDate:compareTime];
Here are a few S.O. threads to help further explain:
Does [NSDate date] return the local date and time?
Why isn't my time zone being saved into my NSDate?
NSDate is not returning my local Time zone /default time zone of device
I have a function which produces the current date depending on the users location. this provides the correct date and time even after daylight saving changes here in the UK.
However when i try to create a string with the date it seems to add an extra hour on for me...
E.g date stored in Coredata is 1/3/2013 12:00 however when converted to a string it appears as 1/3/2013 13:00. What ever i change with locale and timezones don't seem to make a difference.
Any ideas how i can fix this? It might be worth noting that the "Local Date" function i have never creates the date time with the correct timezone.
Code:
+(NSDate*)localDate{
NSDate* date = [NSDate date];
NSTimeZone* sourceTimeZone = [NSTimeZone timeZoneWithAbbreviation:#"GMT"];
NSTimeZone* destinationTimeZone = [NSTimeZone localTimeZone];
NSInteger sourceGMTOffset = [sourceTimeZone secondsFromGMTForDate:date];
NSInteger destinationGMTOffset = [destinationTimeZone secondsFromGMTForDate:date];
NSTimeInterval interval = destinationGMTOffset - sourceGMTOffset;
return [NSDate dateWithTimeInterval:interval sinceDate:date];
}
Formatted Code:
-(NSString*)dateWithTime{
NSDateFormatter*formatter = [[NSDateFormatter alloc]init];
[formatter setDateFormat:#"dd"];
NSInteger day = [[formatter stringFromDate:self]integerValue];
NSInteger fullday = day;
NSString* strDay = #"";
if(day>29){
day = day - 30;
}
else if(day>19){
day = day - 20;
}
else if(day>9){
day = day - 10;
}
if(fullday ==11){
strDay = #"th";
}
else if(fullday ==12){
strDay = #"th";
}
else if(fullday ==13){
strDay = #"th";
}
else if(day == 1){
strDay = #"st";
}
else if(day ==2){
strDay = #"nd";
}
else if(day ==3){
strDay = #"rd";
}
else{
strDay = #"th";
}
[formatter setDateFormat:#"MMMM"];
NSString* month = [formatter stringFromDate:self];
[formatter setDateFormat:#"HH:mm"];
NSString* time = [formatter stringFromDate:self];
return [NSString stringWithFormat:#"%u%# %# %# - %#",fullday,strDay,month,[self yearString],time];
}
EDIT: Even NSDateComponants returns the incorrect time..
NSCalendar *gregorian = [NSCalendar currentCalendar];
NSDateComponents *dateComponents = [gregorian components:(NSHourCalendarUnit | NSMinuteCalendarUnit | NSSecondCalendarUnit) fromDate:self];
Please note that printing NSDate's in the console will always print the date in UTC.
Simply store the [NSDate date] in your database. When the user never changed it's time zone, reading the date from your database and format it will return the correct result.
NSDate objects in Core Data are stored as UNIX timestamp with time zone UTC. When reading and formatting the date object the current time zone of the user is applied.
When storing dates with Core Data and having dependences to different time zones the only way to format dates correctly is to store the appropriate time zone (name of time zone as string) as well. When reading and formatting the date object you have to apply the stored time zone to the dateFormatter. Then you'll get the correct results.
NSDate doesn't know about timezones it's only when converted that the timezone counts, so your localDate method is probably fudging things in a way you don't intend. What you probably need to do is set the timezone for the formatter or calendar to the local zone, so:
[formatter setTimeZone:localTimeZone];
or
[gregorian setTimeZone:localTimeZone];
and leave the value returned by [NSDate date] alone.
Set the locale of dateformatter;
NSLocale *enUSPOSIXLocale = [[NSLocale alloc] initWithLocaleIdentifier:#"en_US_POSIX"];
[dateFormatter setLocale:enUSPOSIXLocale];
Depending on your needs after the initial date/time is set, you may want to be notified if the time zone (including DST) has changed. If so, applicationSignificantTimeChange: would be your friend.
I have a NSString (ex. "2011-04-12 19:23:39"), and what I did to format it to a NSDate was the following:
[inputFormatter setDateFormat:#"yyyy-MM-dd HH:mm:ss"];
NSDate *date = [inputFormatter dateFromString:newDateString];
but what it outputs when I nslog the date is this:
2011-04-12 23:23:39 +0000
which is about 4 hours off. Is there something I missed? Possibly a time zone problem?
The answer in short, is the Date is being returned GMT unless specified otherwise. You can set your timezone to get the correct date. If you plan on using the date in the app to set anything ( like localNotification time or Event ) you will need to do something special with the date because if you set the date in the iPhone it will be set as GMT time and will be off by a few hours. ( in your case 4 hours ). I do this exact thing I just described in one of my apps.
I made a mess of trying to get this to work correctly without having the hours be off. It was a huge PITA to figure out but its working now. I have copied, pasted, and edited my code to share. Again, its messy but it works! The pickerChanged is getting its info from a UIDatePicker
Using the code below. To answer your question, you can stop at "destinationDate". That will return to you the corrected time for your current time zone. I just provided the extra incase you were trying to use the date in the Phone somewhere.
NOTE: for a quick example i put the Event reminder in the same function as the datepicker, you will NOT want to do that otherwise you will have alot of reminders set everytime the wheel scrolls in the datepicker.
The code is below.
- (void)pickerChanged:(id)sender
{
NSLog(#"value: %#",[sender date]);
NSDate* date= [sender date];
NSDateFormatter *formatter=[[[NSDateFormatter alloc]init]autorelease];
[formatter setDateFormat:#"MM/dd/yyyy hh:mm:ss a"];
[formatter setTimeZone:[NSTimeZone systemTimeZone]];
[formatter setTimeStyle:NSDateFormatterLongStyle];
NSString *dateSelected =[formatter stringFromDate:date];
NSString *timeZone = [dateSelected substringFromIndex:12];
NSTimeZone* destinationTimeZone = [NSTimeZone systemTimeZone];
//here we have to get the time difference between GMT and the current users Date (its in seconds)
NSInteger destinationGMTOffset = [destinationTimeZone secondsFromGMTForDate:date];
//need to reverse offset so its correct when we put it in the calendar
correctedTimeForCalendarEvent = destinationGMTOffset + (2*(-1*destinationGMTOffset));
//date to enter into calendar (we will use the correctedTimeForCalendarEvent to correct the time otherwise it will be off by a few hours )
NSDate * destinationDate = [[[NSDate alloc] initWithTimeInterval:destinationGMTOffset sinceDate:date] autorelease];
NSDate * dateForReminder = destinationDate;
// return destinationDate;
NSLog(#"value: %# - %#",destinationDate,dateForReminder);
//DO NOT put this code in this same function this is for a quick example only on StackOverflow
//otherwise you will have reminders set everytime the users scrolled to a different time
//set event reminder
//make sure to import EventKit framework
EKEventStore *eventDB = [[[EKEventStore alloc] init]autorelease];
EKEvent *myEvent = [EKEvent eventWithEventStore:eventDB];
NSString * eventTitle = [NSString stringWithFormat:#"%# - %#",app.dealerBusinessName,serviceOrComments.text];
myEvent.title = eventTitle;
//double check date one more time
NSLog(#"value: %#",destinationDate);
//set event time frame (1 hour) the "initWithTimeInterval" is where we account for the users timezone by adding the correctedTime from GMT to the calendar time ( so its not off by hours when entering into calendar)
myEvent.startDate = [[[NSDate alloc] initWithTimeInterval:correctedTimeForCalendarEvent sinceDate:destinationDate ]autorelease];
myEvent.endDate = [[[NSDate alloc] initWithTimeInterval:3600 sinceDate:myEvent.startDate]autorelease];
myEvent.allDay = NO;
//set event reminders 1 day and 1 hour before
myAlarmsArray = [[[NSMutableArray alloc] init] autorelease];
EKAlarm *alarm1 = [EKAlarm alarmWithRelativeOffset:-3600]; // 1 Hour
EKAlarm *alarm2 = [EKAlarm alarmWithRelativeOffset:-86400]; // 1 Day
[myAlarmsArray addObject:alarm1];
[myAlarmsArray addObject:alarm2];
myEvent.alarms = myAlarmsArray;
[myEvent setCalendar:[eventDB defaultCalendarForNewEvents]];
NSError *err;
[eventDB saveEvent:myEvent span:EKSpanThisEvent error:&err];
if (err == noErr) {
//no error, but do not show alert because we do that below.
}
}
NSDateFormatter use the current device timezone when it created the NSDate object. NSDate stores the date/time in GMT. Therefore by default NSLog will output the date/time in GMT+0. So, there's nothing wrong with your code. Now if you want to output the NSDate to your current timezone, your will have to use a NSDateFormatter object.
Your data and date formatter omit the TimeZone specifier. So something like this:
[inputFormatter setDateFormat:#"yyyy-MM-dd HH:mm:ssZ"];
Would work - the Z is the timezone specifier and will parse both numeric offsets and timezone codes. Although in your case as your input date has no TimeZone information it won't work.
Your correct Time string should be like "2011-04-12 19:23:39 -0400" or "2011-04-12 19:23:39 EST "
Depending on where you get your date from, you should fix that to produce a fully qualified date if you can't do that, you will have to agree timezone offsets with the server or simply 'hard code' a timezone offset and add that number of seconds to your NSDate.
The date is being logged as a UTC date can be seen by the +0000 at the end. The date format you are using to parse the string assumes your local time zone which is presumably 4 hours behind UTC with daylight savings and the standard -5 hours.
Use -[NSDateFormatter setTimeZone:] to provide the date formatter with timezone information. You can use the local time zone, or if you have a fixed time zone associated with the date information, I recommend creating the timezone with the name (such as "America/East") rather than the abbreviation (such as "EST" or "EDT"), since the name does not force daylight savings into effect, but uses the correct daylight savings offset for that date in that timezone.