NSDateFormatter dateFromString returns nil

by

Add this line:

NSDateFormatter *parser = [[NSDateFormatter alloc] init];
[parser setLocale:[[[NSLocale alloc] initWithLocaleIdentifier:@"en_US_POSIX"] autorelease]];

and it will work. By default, NSDateFormatter uses the system’s current locale, which can vary depending on the current user’s preferences. The date string above (@"Tue, 23 Nov 2010 16:14:14 +0000") contains English words (“Tue”, “Sep”) that would potentially not be recognized by the date formatter if the locale would be set to anything other than English.

Moreover, users from non-western cultures might use locales that use a different calendar than the Gregorian calendar that’s used in the western world. If you did not explicitly set the locale, the date formatter might be able to parse the date but the resulting NSDate would represent a whole other point in time.

The locale identifier @"en_US_POSIX" is meant for this purpose. It is guaranteed to not change even if the @”en_US” locale should someday change its default settings.

More Related Contents:

  1. HTML character decoding in Objective-C / Cocoa Touch
  2. Understanding reference counting with Cocoa and Objective-C
  3. When do you make an underscore in front of an instance variable? [duplicate]
  4. Why do you use an underscore for an instance variable, but not its corresponding property? [duplicate]
  5. What are best practices that you use when writing Objective-C and Cocoa? [closed]
  6. Property vs. instance variable
  7. How to write data in plist?
  8. Does UIGestureRecognizer work on a UIWebView?
  9. Open Source Cocoa/Cocoa-Touch POP3/SMTP library?
  10. Do you need to create an NSAutoreleasePool within a block in GCD?
  11. Interaction beyond bounds of UIView
  12. iPhone: Convert date string to a relative time stamp
  13. NSArray Equivalent of Map
  14. writing NSDictionary to plist in my app bundle
  15. Memory Management in Objective-C [duplicate]
  16. How to write a simple Ping method in Cocoa/Objective-C
  17. Objective-C Category Causing unrecognized selector
  18. What’s the best way to put a c-struct in an NSArray?
  19. Obtaining an NSDecimalNumber from a locale specific string?
  20. NSString to NSArray
  21. What’s the difference between “bundle display name” and “bundle name” in cocoa application’s info plist
  22. What is an easy way to break an NSArray with 4000+ objects in it into multiple arrays with 30 objects each?
  23. NSLocale currentLocale always returns “en_US” not user’s current language
  24. Using MD5 hash on a string in cocoa? [duplicate]
  25. How to set a custom font for entire iOS app without specifying size
  26. How to make ui responsive all the time and do background updating?
  27. Multiple value enum in Obj-C
  28. Why tack a protocol of NSObject to a protocol implementation
  29. Convert hex data string to NSData in Objective C (cocoa)
  30. What’s the best way to use Obj-C 2.0 Properties with mutable objects, such as NSMutableArray?

Leave a Comment