Unable to convert original date using dateFromString - objective-c

Question

I am trying to convert a time string using the following code
NSString *origDate = #"2012-12-06T09:27:18+08:00";
NSDateFormatter *df = [[NSDateFormatter alloc] init];
[df setFormatterBehavior:NSDateFormatterBehavior10_4];
[df setDateFormat:#"yyyy-mm-dd HH:mm:ss VVVV"];
NSDate *convertedDate = [df dateFromString:origDate];
However when I print the convertedDate, it returns me null. My guess is that the Date format U am using does not match. How can I modify the code to make it work? What format can I use to match my string?
EDIT (After referring to apple's documentation)
I checked the date format documentation on apple's page and found the following code
NSDateFormatter *rfc3339DateFormatter = [[NSDateFormatter alloc] init];
NSLocale *enUSPOSIXLocale = [[NSLocale alloc] initWithLocaleIdentifier:#"en_US_POSIX"];
[rfc3339DateFormatter setLocale:enUSPOSIXLocale];
[rfc3339DateFormatter setDateFormat:#"yyyy'-'MM'-'dd'T'HH':'mm':'ss'Z'"];
[rfc3339DateFormatter setTimeZone:[NSTimeZone timeZoneForSecondsFromGMT:0]];
// Convert the RFC 3339 date time string to an NSDate.
NSDate *date = [rfc3339DateFormatter dateFromString:rfc3339DateTimeString];
The format above seems to match what I have in the original date string "2012-12-06T09:27:18+08:00". However I am still getting a null value back. Am I getting closer? How else can I update this?

Answer 1

Based on your original input, this format string provided to your date formatter should get the job done:
#"yyyy'-'MM'-'dd'T'HH':'mm':'ssZZZZZ"
Note: I had tested this under Mac OS X 10.8.2.

Answer 2

The format String will parse on iOS6 (not iOS5 -> nil) but it is useless for output, since the parsed date will loose it's timezone information.
Output will be something like "2012-12-06T17:27:18Z" in iOS6 maybe this is depending on wether the timezone is set to GMT.
my Code:
static NSDateFormatter *gXmlDateFormatter = nil;
// lazy init
+ (NSDateFormatter *)xmlDateFormatter
{
// e.g. updateDateTime="2012-09-18T11:06:19+00:00"
if (gXmlDateFormatter == nil) {
// prepare for parsinf Arinc-ISO-XML-dates input
gXmlDateFormatter = [[NSDateFormatter alloc] init];
gXmlDateFormatter = [NSTimeZone timeZoneForSecondsFromGMT:0];
gXmlDateFormatter.locale = [[NSLocale alloc] initWithLocaleIdentifier:#"en_US_POSIX"];
gXmlDateFormatter.dateFormat = #"yyyy'-'MM'-'dd'T'HH':'mm':'ssZZZZZ"; // only parsing! in iOS 6 (iOS5 will parse nil)
// gXmlDateFormatter.dateFormat = #"yyyy'-'MM'-'dd'T'HH':'mm':'ssZ"; // all iOS but with NO colons in timeZone (add/remove)
}
NSLog(#"gXmlDateFormatter:%#",gXmlDateFormatter);
return gXmlDateFormatter;
}
// there's a problem with the above dateformater and iOS5 creating nil-results
+ (NSDate *)dateFromXMLString:(NSString *)arincDateString
{
NSString *dateString = arincDateString;
// xmlDateStrings may contain a ':' in the timezone part. iOS and Unicode DO NOT
// so always remove the xml-standard colon ':' from the timezone to make it iOS/Unicode compatible
// xml: http://www.w3schools.com/schema/schema_dtypes_date.asp
// iOS: http://unicode.org/reports/tr35/tr35-6.html#Date_Format_Patterns)
NSRange zRange = NSMakeRange(arincDateString.length-3, 1);
dateString = [arincDateString stringByReplacingOccurrencesOfString:#":" withString:#"" options:0 range:zRange];
NSDate *date = [self.arincDateFormatter dateFromString:dateString];
if(!date)NSLog(#"PARSING arincDateString:'%#' -> (NSDate*)%# ",arincDateString,date);
return date;
}
+ (NSString *)xmlStringFromDate:(NSDate *)date
{
if( !date ) return nil; // exit on nil date
#autoreleasepool {
NSString *dateString = [self.arincDateFormatter stringFromDate:date];
// iOS5 does not use a ':' in the timeZone part but xml needs it
// so allways add the xml-standard colon ':' into the timezone
NSMutableString *string = [NSMutableString stringWithString:dateString];
if( 22 < string.length ) { // prevent crashing
[string insertString:#":" atIndex:22];
} else {
NSLog(#"date output string too short:%d<22",string.length);
}
dateString = string;
if(!dateString)
NSLog(#"OUTPUT '%#' -> (NSString*)%#",date,dateString);
return dateString;
}
}