Convert NSString back to NSDate - ios

I am using NSDateFormatter to convert the current date to a string (in the format: February 16, 2013). How can I convert this string back to a NSDate object?
NSString *dateString = [NSDateFormatter localizedStringFromDate:[NSDate date] dateStyle:NSDateFormatterLongStyle timeStyle:NSDateFormatterNoStyle];
The problem appears to be that the month is written out (February vs. 02), and other questions only explain to use NSDateFormatter with a format such as MM-dd-yyyy, which I do not believe is possible here. Must I parse this date manually, convert February to 02, and go from there?

You can use dateFromString of the same NSDateFormatter class to perform backward conversion.
To make it work you need to define dateStyle, so parser will know how text string should be parsed. For the date style that you provided code below will work:
NSDateFormatter *dateFormatter = [[NSDateFormatter alloc] init];
[dateFormatter setDateStyle:NSDateFormatterLongStyle];
NSDate *date = [dateFormatter dateFromString:#"February 16, 2013"];
NSLog(#"%#", date);

If you want to be able to use localized date formats, you should go with templates
NSString *dateString = [NSDateFormatter localizedStringFromDate:[NSDate date]
dateStyle:NSDateFormatterLongStyle
timeStyle:NSDateFormatterNoStyle];
NSLog(#"%#", dateString);
NSDateFormatter *dateFormatter = [[NSDateFormatter alloc] init];
[dateFormatter setDateFormat:[NSDateFormatter dateFormatFromTemplate:#"MMMdY"
options:0
locale:[NSLocale currentLocale]]];
NSLog(#"%#", [dateFormatter dateFromString:dateString]);

Since you have a fixed format that you wish to parse, you must setup the date formatter with the locale of en_US_POSIX. Then you must set he date format to MMMM dd, yyyy. This will pare any date string that has the full month name, the month day, a comma, then the four-digit year.

Related

NSDateFormatter dateFromString return wrong year

I have these following snippet.
NSDateFormatter *formatter = [[NSDateFormatter alloc] init];
[formatter setDateFormat : #"yyyy/MM/dd"];
NSString *timeStr = #"2015/05/16";
NSDate *timeDate = [formatter dateFromString:timeStr];
But when I print timeDate in console,the output is werid.The year becomes 4003.
4003-05-16 16:00:00 +0000
I test it in iPad 8.3(12F69)(not simulator).System time zone is Beijing.
Any help is appreciated.
The issue is the locale of the formatter. If you want to use gregorian calendar regardless of the device settings, you generally should set locale to en_US_POSIX.
formatter.locale = [NSLocale localeWithLocaleIdentifier:#"en_US_POSIX"];
See Apple Technical Q&A #1480. This is geared towards RFC 3339/ISO 8601 dates, but it really applies anywhere you're trying to use standard calendar for converting date string for internal purposes (i.e. as opposed to those dates that are presented to the end user in the UI, which generally should use the device's locale).
Try this... Just need to add last line while printing output.
NSString *timeStr = #"2015/05/16";
NSDateFormatter *formatter = [[NSDateFormatter alloc] init];
formatter.dateFormat = #"yyyy-MM-dd";
NSDate *Date = [formatter dateFromString:timeStr];
NSLog(#"Date =%#", [formatter stringFromDate:Date]);

IOS - Date formatting from string

I would like to format a date to display in a uitableview custom cell
The data is passed into the app from a CMS - it is provided as a string in the following format and stored in a date type variable-
2014-04-15 10:10:45 +0000
Our app will initially be UK based - so I need to convert the format into DD/MM/YYYY format.
I tried the following code to parse my date (dateadded which is of type date).
NSDateFormatter *formatter = [NSDateFormatter new];
cellRecP.artDate.text = [formatter stringFromDate:resItem.dateadded];
but this just returns null - i guess the date format provided above is not anything that stringfromdate understands - is there any other way to format date?
Use an 'NSDateFormatter'
NSDateFormatter* newFormatter = [[[NSDateFormatter alloc] init] autorelease];
with this format to parse the string
[newFormatter setDateFormat:#"yyyy-MM-dd hh:mm:ss zzz"];
NSDate* aDate = [newFormatter dateFromString:dateString];
and you should get a valid 'NSDate' object
Try This and also Checkout this All Formate It is really good and helpful.
NSString *yourString = #"2014-04-15 10:10:45 +0000";
NSDateFormatter *df = [[NSDateFormatter alloc]init];
[df setTimeZone:[NSTimeZone systemTimeZone]];//Set Your Timezone
[df setDateFormat:#"yyyy-MM-dd HH:mm:ss Z"];//You have to set this formate.
NSDate *dd = [df dateFromString:yourString];//This will convert into date;
//Now you can set your formate.
[df setDateFormat:#"dd/MM/yyyy"];
NSString *str = [df stringFromDate:dd];
You need an NSDateFormatter and a proper unicode parse string. NSDateFormatter by default automatically checks the device locale setting the correct output.
This is an example from some code of mine:
NSDateFormatter *dateWriter = [[NSDateFormatter alloc] init];
dateWriter.dateFormat = #"yyyy'-'MM'-'dd' 'HH':'mm':'ss' 'ZZZ";
dateWriter.dateStyle = NSDateFormatterMediumStyle;
dateWriter.timeStyle = NSDateFormatterMediumStyle;
Pay attention that date formatters are pretty expensive to create.

Problems converting a string date to NSDate

I have this string date:
2014-04-21T07:55:13Z
when I convert that to NSDate I have the hour like 6:55... 1 hours less. WHY?
This is the code I am using to convert:
NSDateFormatter *dateFormatter = [[NSDateFormatter alloc] init];
[dateFormatter setDateFormat:#"yyyy-MM-dd'T'HH:mm:ss'Z'"];
NSDate *newDate = [dateFormatter dateFromString:dateStr];
newDate is now 2014-04-21 06:55:13 +0000 !!!???
what is wrong?
NOTE: That one hour less would make sense if the date was my local time (GMT+1) being converted to GMT. But if that Z is zero offset ( = GMT) the date is already GMT.
I don't think your code is wrong. using this code:-
NSString *dateStr = #"2014-04-21T07:55:13Z";
// Convert string to date object
NSDateFormatter *dateFormat = [[NSDateFormatter alloc] init];
[dateFormat setDateFormat:#"yyyy-MM-dd'T'HH:mm:ss'Z'"];
NSDate *date = [dateFormat dateFromString:dateStr];
NSLog(#" date log %#",date); //2014-04-21 02:25:13 +0000 output
// Convert date object to desired output format
[dateFormat setDateFormat:#"yyyy-MM-dd'T'HH:mm:ss'Z'"];
dateStr = [dateFormat stringFromDate:date];
NSLog(#"string %#",dateStr); //2014-04-21T07:55:13Z output
but NSLog of NSDATE is not output correct according to this NSDate Format outputting wrong date so your code is right.
The NSDate doesn't know anything about formatting (just date information), and the NSDateFormatter doesnt really know anything about dates, just how to format them. So you have to use methods like -stringFromDate: for know that is current or not to actually format the date for pretty human-readable display.
NSLog(#" date is %#",[dateFormat stringFromDate:date]);

Date format of Tapku Calendar

In the API , the selected day format is like 2013-11-01T23:00:00%2B0000
But my date format is like this: 2013-11-01T23:00:00+0000
To convert, I have used below code:
NSString *plus = [NSString stringWithFormat:#"%#%#", [timeStamp substringToIndex:[timeStamp length]-5], #"%2B0000"];
Instead of (+) the unicode of plus which is (%2B).
But when I select the day from Tapku calender, I receive the error which says date format is wrong. How can I fix this problem?
NSDate *tempDate=toDate;
NSDateFormatter *df = [[NSDateFormatter alloc] init];
[df setDateFormat:#"yyyy-MM-dd HH:mm:ss zzzz"];
[periodOfInspectionToTextField setText:[NSString stringWithFormat:#"%#",[df stringFromDate:d]]];
toDate=[df dateFromString:periodOfInspectionToTextField.text];
You need to set the dateformat of tapku which is below:-
[YYYY-MM-DD hour:minute:second];
Also follow this link for more details.
Tapku library -what is the date format in day view
First, you need to unescape the date string from the API to remove the percent escapes:
NSString *dateString = [#"2013-11-01T23:00:00%2B0000" stringByReplacingPercentEscapesUsingEncoding:NSUTF8StringEncoding];
This will give a date string of 2013-11-01T23:00:00+0000. Then you need to parse this string into a NSDate object:
NSDateFormatter *formatter = [[NSDateFormatter alloc] init];
[formatter setDateFormat:#"yyyy-MM-dd'T'HH:mm:sszzzz"];
NSDate *date = [formatter dateFromString:dateString];

iOS how to show a date in another language,

I've recently been working on a French version of our application use NSLocalizedStrings, so far everything is working great.
But my problem now is with dates. I show dates often in my application, in different formats, depending on the situation.
Ex:
-Fri Feb 22, 2013
-Monday February 18, 2013
-Feb 18
-Dec 5, 2012
The thing is, dates in French are not only different in terms of the name of the month, but also the order in which month, day and year appear.
Ex:
-Dec 5, 2012 would be 5 Dec 2012
-Monday February 18, 2013 would be Lundi le 18 Fevrier 2013.
I have the individual month/day names in my Localizable.string files, but how do I manage the order of how it's displayed.
Should I have an if statement that checks the current device language like so?:
NSString *currentLanguage = [[NSLocale preferredLanguages] objectAtIndex:0];
if([currentLanguage isEqualToString:#"fr"])
{
//Handle French logic
}
This is probably not the best way to go about it.
Any ideas?
You should use an NSDateFormatter and feed it your desired NSLocale like this:
NSDateFormatter *dateFormatter = [[NSDateFormatter alloc] init];
dateFormatter.locale = [[NSLocale alloc] initWithLocaleIdentifier:#"nl_NL"];
dateFormatter.dateFormat = #"EEEE d MMMM yyyy HH:mm";
'EEEE' is the full name of the day of the week, which, in my case, will be displayed in dutch.
Use NSDateFormatter. For example:
NSDateFormatter *dateFormatter = [[NSDateFormatter alloc] init];
[dateFormatter setDateStyle:NSDateFormatterMediumStyle];
[dateFormatter setTimeStyle:NSDateFormatterNoStyle];
NSDate *date = [NSDate dateWithTimeIntervalSinceReferenceDate:162000];
NSString *formattedDateString = [dateFormatter stringFromDate:date];
NSLog(#"formattedDateString: %#", formattedDateString);
NSDateFormatterMediumStyle will automatically format the date according to the user's preference (English, French, etc.).
If you need custom styling and the app runs in iOS 4.0+, you can use a custom template in your date formatter:
NSString *formatString = [NSDateFormatter dateFormatFromTemplate:#"EdMMMyyy" options:0
locale:[NSLocale currentLocale]];
NSDateFormatter *dateFormatter = [[NSDateFormatter alloc] init];
[dateFormatter setDateFormat:formatString];
NSString *todayString = [dateFormatter stringFromDate:[NSDate date]];
NSLog(#"todayString: %#", todayString);
Set proper locale to your NSDateFormatter when you convert date to string, then date formatter will handle all specifics of formats depending on user settings for you:
NSDateFormatter *formatter = ... // Create and setup formatter
[formatter setLocale:[NSLocale autoupdatingCurrentLocale]];
// Now you can convert date to string
That's probaly much easier:
There is something which is called
NSDateFormatterShortStyle,
NSDateFormatterMediumStyle
NSDateFormatterLongStyle
Set Date and Time components individually:
[dateFormatter setDateStyle:NSDateFormatterMediumStyle];
[dateFormatter setTimeStyle:NSDateFormatterNoStyle];
Ios will format that correctly if the language of the user.
Further look at Data Formatting Guide
I would try the class function localizedStringFromDate:dateStyle:timeStyle: in NSDateFormatter before attempting to use the NSDateFormatter and a template (from Unicode Technical Standard #35):
Example:
[NSDateFormatter localizedStringFromDate:dateTime dateStyle:NSDateFormatterMediumStyle timeStyle:NSDateFormatterNoStyle];
You can select both different date and time outputs of various lengths detailed in the docs.
Apple documentation: NSDateFormatter localizedStringFromDate:dateStyle:timeStyle:

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