IOS: Converting NSDate to NSString gives nil value

Question

Where is my mistake? I have an NSDate with this format (data: 14/05/2013 10:52:27) and I have to obtain an NSString.

   NSLog(@"Data: %@",lettureObj.data);

   NSDateFormatter *outputDateFormatter = [[NSDateFormatter alloc] init];
   [outputDateFormatter setDateFormat:@"dd/MM/yyyy HH:mm:ss"];
   NSString *data  = [outputDateFormatter stringFromDate:lettureObj.data];

If I use NSString *data= lettureObj.data It works good but I have an XCode warning — Alessandro Mattiuzzi, May 14 '13 at 09:12
@Amar: Incompatible pointer type `stringFromDate` expects date object — Deepesh Gairola, May 14 '13 at 09:15
lettureObj.data is NSString instead of NSDate, are you doing it right? Or do you want to convert NSString to NSDate instead? — Amar, May 14 '13 at 09:16
@AlessandroMattiuzzi: What is the data type of `lettureObj.data` ? Are you sure its `NSDate` object? — Deepesh Gairola, May 14 '13 at 09:17
@Alessandro Mattiuzzi: Can u give what "NSLog(@"Data: %@",lettureObj.data);" is printing? — Augustine P A, May 14 '13 at 09:19
lettureObj.data is a NSdate but i assign it: lettureObj.data = dateString; — Alessandro Mattiuzzi, May 14 '13 at 09:21
Then your date formatter should work properly. My doubt "lettureObj.data" may not be an NSDate object. To check that please try the line of code given. if([lettureObj.data isKindOfClass:[NSDate class]]) NSLog(@"Its NSDate Object"); else NSLog(@"Its not an NSDate Object"); — Augustine P A, May 14 '13 at 09:29
SOLVED BRO. The problem was that I assign an NSString to lettureObj.data when i did ettureObj.data = dateString. — Alessandro Mattiuzzi, May 14 '13 at 09:32
possible duplicate of [Convert NSDate to NSString](http://stackoverflow.com/questions/576265/convert-nsdate-to-nsstring) — jww, Aug 13 '14 at 07:04

score 0 · Answer 1 · answered May 14 '13 at 09:07

use following functions

//*********************************Convert String into Date **********************

- (NSDate*) convertStringToDate:(NSString*)dateStr dateformat:(NSString*)dateformat
{
    // Convert string to date object
    //dateformat like :@"yyyy-MM-dd"]
    NSDateFormatter *dateFormatter = [[NSDateFormatter alloc] init];
    [dateFormatter setDateFormat:dateformat];
    NSDate *date = [dateFormatter dateFromString:dateStr];  
    [dateFormatter release];//For NON-ARC
    return date;
}

//*********************************Convert date into String **********************

- (NSString*) convertDateToString:(NSDate*)date  dateformat:(NSString*)dateformat
{
    // Convert date object to desired output format
    NSDateFormatter *dateFormat1 = [[NSDateFormatter alloc] init];
    [dateFormat1 setDateFormat:dateformat];
    NSString *dateStr = [dateFormat1 stringFromDate:date];  
    [dateFormat1 release];//For NON-ARC

    return dateStr;
}

Hope it will help you

It's the same thing I do boss. But not works for me here.... — Alessandro Mattiuzzi, May 14 '13 at 09:11
@AlessandroMattiuzzi: These conversion methods should work fine provided you are passing correct data type arguments. — Amar, May 14 '13 at 09:18

score 0 · Accepted Answer · answered May 14 '13 at 09:17

0

The problem here is the lettureObj.data is NSString and what you need is to convert it into date primarly to have an NSDate object

answered May 14 '13 at 09:17

Lithu T.V

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yes I think this is the problem...but in my h. file i defined it @property (nonatomic, copy) NSDate *data; – Alessandro Mattiuzzi May 14 '13 at 09:25
Now I do lettureObj.data = [dateFormatter dateFromString:dateString]; AND WORKS – Alessandro Mattiuzzi May 14 '13 at 09:34
Thats it :) happy coding – Lithu T.V May 14 '13 at 09:35

score 0 · Answer 3 · answered May 14 '13 at 09:25

try this

   NSString *strTemp = [NSString stringWithFormat:@"%@",lettureObj.data];

   NSDateFormatter *dateFormat = [[NSDateFormatter alloc] init];
   [dateFormat setDateFormat:@"dd/MM/yyyy HH:mm:ss"];
   NSDate *date = [dateFormat dateFromString:strTemp];
   [dateFormat release];


   NSDateFormatter *outputDateFormatter = [[NSDateFormatter alloc] init];
   [outputDateFormatter setDateFormat:@"dd/MM/yyyy HH:mm:ss"];

  NSString *data  = [NSString stringWithFormat:@"%@",[outputDateFormatter stringFromDate:date]];

IOS: Converting NSDate to NSString gives nil value

3 Answers3