Get time without time portion or timezone difference

Question

I'm a iOS developer of the iWorld. I've developed several iPhone/iPad apps before. I couldn't get correct time information on iPhone several times. I think that is due to localization.

For example, I have code to get the time-truncated today. (ex : "05-04-2012 00:00:00") But that code always return 8 hours ago to that I've expected. (ex : "05-03-2012 16:00:00) The code that I've worked are as following.

NSDate *today = [NSDate date];
NSCalendar *calender = [[NSCalendar alloc] initWithCalendarIdentifier:NSGregorianCalendar];
NSDateComponents *components = [calender components:NSYearCalendarUnit | NSMonthCalendarUnit | NSDayCalendarUnit fromDate:today];
today = [calender dateFromComponents:components];
NSDateFormatter *formatter = [[NSDateFormatter alloc] init];
[formatter setDateFormat:@"MM-dd-yyyy hh:mm:ss"];
NSString *todayString = [formatter stringFromDate:today];
NSLog(@"Today is %@", todayString);

I'd like to hear from you to resolve this problem. Thanks for your time.

I'd like to know to know the correct midnight time. Because I have to compare date against database date. For example, I have to find the record for today those are between 05-04-2012 00:00:00 and 05-05-2012 00:00:00 for just today. — Pei, May 04 '12 at 15:02
This might do it then: http://stackoverflow.com/questions/1268509/convert-utc-nsdate-to-local-timezone-objective-c — trojanfoe, May 04 '12 at 15:28
Thanks, trojanfoe. And I've found some useful things on SO just now. I've found "today = [today dateByAddingTimeInterval:[[NSTimeZone localTimeZone] secondsFromGMT]];" — Pei, May 04 '12 at 15:51

score 0 · Answer 1 · answered May 04 '12 at 16:21

0

Set timezone to UTC

    NSDateFormatter *dateFormatter = [[NSDateFormatter alloc] init];
    NSTimeZone *timeZone = [NSTimeZone timeZoneWithName:@"UTC"];
    [dateFormatter setTimeZone:timeZone];

answered May 04 '12 at 16:21

Kirby Todd

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He wants local time so should be using [NSTimeZone localTimeZone] – lnafziger May 04 '12 at 16:46

score 0 · Accepted Answer · answered May 07 '12 at 09:19

I've found that code that calculates correct midnight time. Now I find that following code logs "Today is 05-07-2012 00:00:00" rather than "05-06-2012 16:00:00"

NSDate *today = [NSDate date];
NSCalendar *calender = [[NSCalendar alloc] initWithCalendarIdentifier:NSGregorianCalendar];
NSDateComponents *components = [calender components:NSYearCalendarUnit | NSMonthCalendarUnit | NSDayCalendarUnit fromDate:today];
today = [calender dateFromComponents:components];

today = [today dateByAddingTimeInterval:[[NSTimeZone localTimeZone] secondsFromGMT]];

NSDateFormatter *formatter = [[NSDateFormatter alloc] init];
[formatter setDateFormat:@"MM-dd-yyyy hh:mm:ss"];
NSString *todayString = [formatter stringFromDate:today];
NSLog(@"Today is %@", todayString);

Thanks for SO.

Get time without time portion or timezone difference

2 Answers2