NSDate and NSDateFormatter return invalid CFStrinfRef - objective-c

I've one problem with NSDate and NSDateFormatter.
From this NSString
NSString *startDate = #"Thu, 19 Apr 2012 13:09:56 +0000";
I would obtain a date localized with current locale like this "Thu, 19 Apr 2012 13:09".
I've elaborate this code but the 'endDate' string return nil (within the debugger obtain 'invalid CFStringRef').
[NSDateFormatter setDefaultFormatterBehavior:NSDateFormatterBehavior10_4];
NSDateFormatter *dateFormatter = [[[NSDateFormatter alloc] init] autorelease];
[dateFormatter setDateFormat:#"EEE, dd MMM yyyy HH:mm:ss ZZZ"];
NSDate *dateFromString = [dateFormatter dateFromString:startDate];
[dateFormatter setDateFormat:#"EEE dd MMM yyyy HH:mm"];
[dateFormatter setLocale:[NSLocale currentLocale]];
NSString *endDate = [dateFormatter stringFromDate:dateFromString];
Where is the bug?
Alex.

It seems that the code executed in a non-US locale. I use non-US locales. I have the same nil output also.
It seems like we need to setLocale: before setDateFormat:.
Below code works ok:
NSDateFormatter *dateFormatter = [[[NSDateFormatter alloc] init] autorelease];
NSLocale *usLocale = [[[NSLocale alloc] initWithLocaleIdentifier:#"en_US"] autorelease];
[dateFormatter setLocale:usLocale];
[dateFormatter setDateFormat:#"EEE, dd MMM yyyy HH:mm:ss ZZZ"];

Ya its working correctly..Try removing autorelease from your dateFormatter and then try it again.
And i hope this link is same as yours
Invalid CFStringRef issue
Try this answer and change your format option with "ZZ" and not "ZZZ".

Related

Converting an NSString result from SQLite into a formatted NSDate

I know that it sounds incessantly familiar, but most of the suggested solutions on SO have not worked for me for some strange reason.
I have a date string returned from an SQLite query as an NSString in this format:
2019-06-10 13:45:33
However, when any of the suggested date formatter solutions are applied, with or without timezone localisation, I keep getting such a result:
Mon Jun 10 13:45:33 2019
This is one of the routines I've tried, among many others:
NSString * dateString = #"2019-06-10 13:45:33";
NSDateFormatter *dateFormatter = [[NSDateFormatter alloc] init];
[dateFormatter setDateFormat:#"yyyy-MM-dd HH:mm:ss"];
//[dateFormatter setDateFormat:#"YYYY-MM-dd HH:mm:ss"];
//[dateFormatter setDateFormat:#"yyyy-MM-dd HH:mm:ss ZZZ"];
NSDate *dateFromString = [[NSDate alloc] init];
dateFromString = [dateFormatter dateFromString:dateString];
// dateFromString > Mon Jun 10 13:45:33 2019
Could I be doing something wrong or is there some missing step in the conversion?
TIA.
I could guess that you wanted another output format, if it is the case then you could try code like this:
NSString * dateString = #"2019-06-10 13:45:33";
NSDateFormatter *dateFormatter = [[NSDateFormatter alloc] init];
[dateFormatter setDateFormat:#"yyyy-MM-dd HH:mm:ss"];
//[dateFormatter setDateFormat:#"YYYY-MM-dd HH:mm:ss"];
//[dateFormatter setDateFormat:#"yyyy-MM-dd HH:mm:ss ZZZ"];
NSDate *dateFromString = [[NSDate alloc] init];
dateFromString = [dateFormatter dateFromString:dateString];
NSDateFormatter *printDateFormatter = [[NSDateFormatter alloc] init];
printDateFormatter.dateStyle = NSDateIntervalFormatterMediumStyle;
printDateFormatter.timeStyle = NSDateIntervalFormatterMediumStyle;
NSLog(#"%#", [printDateFormatter stringFromDate:dateFromString]);
The result will be:
10 Jun 2019 at 13:45:33
Use a different formatter to format the string from the date. For example:
NSDateFormatter * formatter=[[NSDateFormatter]alloc]init];
formatter.dateStyle = NSDateFormatterMediumStyle;
formatter.timeStyle = NSDateFormatterNoStyle;
NSString * formattedDateString = [formatter stringFromDate:date];
setDateFormat is for inputting date strings and getting NSDates.
dateStyle and timeStyle is for formatting dateStrings from NSDates.

Objective C - Convert DateTime to Local DateTime

I am pretty new to Objective C and it has been horrible experience to get the current device datetime in systemTimeZone. This is what I have:
NSDate *now = [NSDate date];
NSDateFormatter *DateFormatter=[[NSDateFormatter alloc] init];
[DateFormatter setTimeZone:[NSTimeZone systemTimeZone]];
[DateFormatter setDateFormat:#"MM-dd-yyyy HH:mm"];
NSString *currentDateTime = [DateFormatter stringFromDate:now];
NSDate *curDate = [DateFormatter dateFromString:currentDateTime];
Line 5 NSString has the correct local datetime in currentDateTime string variable. But Line 6 again switches back to UTC DateTime. I do not understand why it would switch back to UTC even though the DateFormatter has the systemTimezone set. Can you please help me find out what is that I am missing?
Just set the timeZone in the dateFormatter, This code is enough
NSString *dateString = #"24 08 2011 09:45PM";
NSDateFormatter *dateFormatter = [[NSDateFormatter alloc] init];
[dateFormatter setDateFormat:#"dd MM yyyy hh:mma"];
NSTimeZone* sourceTimeZone = [NSTimeZone timeZoneWithAbbreviation:#"BST"];
[dateFormatter setTimeZone:sourceTimeZone];
NSDate *dateFromString = [dateFormatter dateFromString:dateString];
The dateFromString will now have the date 24 08 2011 08:45PM(GMT).. Then to convert this to string with local time just code the following,
NSDateFormatter *dateFormatter = [[NSDateFormatter alloc] init];
[formatter setTimeZone:[NSTimeZone localTimeZone]];
[formatter setLocale:[NSLocale systemLocale]];
[dateFormatter setDateFormat:#"dd MM yyyy hh:mma"];
NSString *stringFromDAte = [dateFormatter stringFromDate:dateString];
or You can also try this one:
NSTimeInterval seconds; // assume this exists
NSDate* ts_utc = [NSDate dateWithTimeIntervalSince1970:seconds];
NSDateFormatter* df_utc = [[[NSDateFormatter alloc] init] autorelease];
[df_utc setTimeZone:[NSTimeZone timeZoneWithName:#"UTC"]];
[df_utc setDateFormat:#"yyyy.MM.dd G 'at' HH:mm:ss zzz"];
NSDateFormatter* df_local = [[[NSDateFormatter alloc] init] autorelease];
[df_local setTimeZone:[NSTimeZone timeZoneWithName:#"EST"]];
[df_local setDateFormat:#"yyyy.MM.dd G 'at' HH:mm:ss zzz"];
NSString* ts_utc_string = [df_utc stringFromDate:ts_utc];
NSString* ts_local_string = [df_local stringFromDate:ts_utc];
// you can also use NSDateFormatter dateFromString to go the opposite way
Table of formatting string parameters:
https://waracle.com/iphone-nsdateformatter-date-formatting-table/
If performance is a priority, you may want to consider using strftime
https://developer.apple.com/legacy/library/documentation/Darwin/Reference/ManPages/man3/strftime.3.html

NSDateFormatter dateFromString conversion

I am having problems with conversion of NSString object to NSDate. Here is what I want to do:
I am downloading an RSS Message from the internet. I have the whole message parsed by NSXMLParser. After that, I have parts like , or saved to particular NSStrings. I want to convert element (that includes publication date of RSS Message) to NSDate so that I could perform some operations on it like on a date object (e.g. sorting, showing on a clock etc.). Here is the way my looks like:
"Wed, 25 Sep 2013 12:56:57 GMT"
I tried to convert it to NSDate in this way:
*//theString is NSString containing my date as a text
NSDate *dateNS = [[NSDate alloc] init];
NSDateFormatter *dateFormatter = [[NSDateFormatter alloc] init];
[dateFormatter setDateFormat:#"EEE, dd MMM yyyy hh:mm:ss ZZZ"];
dateNS = [dateFormatter dateFromString:theString];*
However, after doing above code, dateNS always appear to be (null).
My question is simple: what is the right way to convert NSString with date formatted like this to NSDate object?
By the way, I have seen the website
http://www.unicode.org/reports/tr35/tr35-25.html#Date_Format_Patterns
It seems that there are many ways to format particular date, but I could not find what I am doing wrong.
Your problem is the your date formatter has not identical fort as your date string:
You should set date formatter the same format like your date string
My Example:
// Convert string to date
NSString *beginString = #"Sat, 30 Dec 2013 14:45:00 EEST";
//beginString = [beginString stringByReplacingOccurrencesOfString:#"EEST" withString:#""];
//beginString = [beginString stringByTrimmingCharactersInSet:[NSCharacterSet whitespaceAndNewlineCharacterSet]];
dateFormat = [[NSDateFormatter alloc] init];
[dateFormat setLocale:[[NSLocale alloc] initWithLocaleIdentifier:#"en_GB"]];
[dateFormat setTimeZone:[NSTimeZone timeZoneWithName:#"Europe/Helsinki"]];
[dateFormat setDateFormat:#"EEE, dd MMM yyyy HH:mm:ss z"];
dateFromString = [dateFormat dateFromString:beginString];
//NSLog(#"Begin string: %#", beginString);
//NSLog(#"not formated: %#", dateFromString);
// Convert Date to string
[dateFormat setTimeZone:[NSTimeZone localTimeZone]];
[dateFormat setLocale:[[NSLocale alloc] initWithLocaleIdentifier:#"ru_RU"]];
[dateFormat setDateFormat:#"dd MMMM yyyy"];
myStrDate = [dateFormat stringFromDate:dateFromString];
[currentTitle setPubDate:myStrDate];
NSDate * dateNS = [[NSDate alloc] init]; is useless, you don't need to allocate any date object.
NSDateFormatter * dateFormatter = [[NSDateFormatter alloc] init];
[dateFormatter setDateFormat:#"EEE, dd MMM yyyy HH:mm:ss ZZZ"];
NSLog(#"%#", [dateFormatter dateFromString:#"Wed, 25 Sep 2013 12:56:57 GMT"]);
Outputs the date correctly, are you sure theString isn't nil?

Change format of date

I got a NSString *string = #"2012-10-24 23:00:00 +0000";
And I want to convert that to a normal format 24 october 2012
I use the following code. But it keeps crashing. Can anyone help me?
NSDateFormatter *dateformat = [[NSDateFormatter alloc] init];
[dateformat setDateFormat:#"yyyy MM dd HH:mm:SS zzz"];
NSDate *dateNS = [dateformat dateFromString:date];
[dateformat setDateFormat:#"dd MM yyyy"];
date = [dateformat stringFromDate:dateNS];
[dateformat release]
It keeps crashing because it can't create the NSDate from the input date because the dateformat is incorrect. it missing the - between the date and the seconds are ss not SS.
Also you need a date formate with MMMM to get the months full name:
NSString *string = #"2012-10-24 23:00:00 +0000";
NSDateFormatter *dateformat = [[NSDateFormatter alloc] init];
[dateformat setDateFormat:#"yyyy-MM-dd HH:mm:ss zzz"];
NSDate *dateNS = [dateformat dateFromString:string];
[dateformat setDateFormat:#"dd MMMM yyyy"];
NSString *date = [dateformat stringFromDate:dateNS];
[dateformat release];

NSString to NSDate returns wrong date

I try to convert my NSString to NSDate object, but NSDateFormatter returns me a strange value.
Here is code:
NSDateFormatter *dateFormat = [[NSDateFormatter alloc] init];
[dateFormat setDateFormat:#"yyyy-MM-dd HH:mm"];
NSDate *date = [dateFormat dateFromString:#"2012-08-15 00:00"];
[dateFormat release];
date value is 2012-08-14 21:00 +0000. It is 3 hours difference between NSString value and NSDate value. I think I've missed something, but I don't know what.
This is what i use:
NSDateFormatter *dateFormat = [[NSDateFormatter alloc] init];
[dateFormat setDateFormat:#"yyyy-MM-dd HH:mm:ss ZZZ"];
NSDate *date = [dateFormat dateFromString:#"2012-08-15 00:00:00 +0000"];
NSLog(#"\n\n DATE: %# \n\n\n", date);
The +0000 is timezone, so make sure you use your timezone, like +0400.
Edit:
If you can't change the string, you can use this code to do it:
NSDateFormatter *dateFormat = [[NSDateFormatter alloc] init];
[dateFormat setDateFormat:#"yyyy-MM-dd HH:mm"];
[dateFormat setTimeZone:[NSTimeZone timeZoneForSecondsFromGMT:0]];
NSDate *date = [dateFormat dateFromString:#"2012-08-15 00:00"];
As i knew NSDate holds Grinwich time, so if you are in Moscow time zone, everything is wright
In objective c for NSDate if you did not set the setTimeZone, NSDate will take default timezone as localTimeZone. so if you need to get the exact date which you give as NSString string format, you need to setTimeZone as UTC. Follow the sample code, I guess it will be helpful for you.
NSDateFormatter *loacalformatter=[[NSDateFormatter alloc]init];
[loacalformatter setDateFormat:#"yyyy-MM-dd HH:mm:ss"];
NSDate *localDate =[loacalformatter dateFromString:#"2012-08-15 00:00"];
NSLog(#"localDate :%#",localDate);
NSDateFormatter *UTCformatter=[[NSDateFormatter alloc]init];
[UTCformatter setTimeZone:[NSTimeZone timeZoneWithName:#"UTC"]];
[UTCformatter setDateFormat:#"yyyy-MM-dd HH:mm:ss"];
NSDate *UTCDate =[UTCformatter dateFromString:#"2012-08-15 00:00"];
NSLog(#"UTCDate :%#",UTCDate);
UTCDate :2012-08-15 00:00 +0000 (GMT+00:00)
As suggested in the comments, if the date you receive is UTC then you need to convert it to your local timezone. Apple recommend you always use a properly configured NSDateFormatter when displaying dates, to handle localisation issues.
Here's some example code for turning an NSDate into an NSString:
NSDate *date = // initialised elsewhere
NSDateFormatter *dateFormat = [[NSDateFormatter alloc] init];
dateFormat.locale = [NSLocale currentLocale];
dateFormat.timeZone = [NSTimeZone localTimeZone];
dateFormat.timeStyle = NSDateFormatterShortStyle;
dateFormat.dateStyle = NSDateFormatterShortStyle;
dateFormat.locale = [NSLocale currentLocale];
NSString *dateAsString = [dateFormat stringFromDate:date];