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iOS

Posted by agreatdaytocode
agreatdaytocode
24,757 Points

JSON and NULL values errors

Anyone have a solution for dealing with NULL values that are returned when pulling JSON data?

I'm currently getting the following error message: 2014-06-11 07:11:56.829 [494:6107] LabelValue is =====> 2014-06-11 07:11:56.830[494:613] -[NSNull length]: unrecognized selector sent to instance 0x101b56b50 2014-06-11 07:11:56.846[494:613] *** Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: '-[NSNull length]: unrecognized selector sent to instance 0x101b56b50' *** First throw call stack: BLA BLA BLA

Example data being returned: 

 {
               dateAdded = "2014-04-22T16:50:32Z";
                eventDate = "<null>"; //This is the issue #:( 
                id = 71496;
                name = Test;
                ownerName = "name";
                webLink = "someurl";
            },

2 Answers

Marcus Vieira
Marcus Vieira
7,877 Points

Hi Aaron!

You might wanna check if the JSON block has a null element or not:

if (eventDate == (id)[NSNull null]) {
    // eventDate is null 
}

or you can do:

if (eventDate != (id)[NSNull null]) {
    // eventDate is not null 
    // you are free to parse it :)
}

So you won't have to add an extra else to do your parsing.

I hope this helps!

agreatdaytocode
agreatdaytocode
24,757 Points

Hi Marcus, thanks I'll give this a shot.

Marcus Vieira
Marcus Vieira
7,877 Points

No problem :) let me know if it works!

agreatdaytocode
agreatdaytocode
24,757 Points

Yeah I can't get it to work. I'm sure I'm doing something wrong here. I'll keep working on it.

Marcus Vieira
Marcus Vieira
7,877 Points

Is it still throwing the same error ?

agreatdaytocode
agreatdaytocode
24,757 Points

Sure is : (

Marcus Vieira
Marcus Vieira
7,877 Points

Can you show me your parser ?

agreatdaytocode
agreatdaytocode
24,757 Points 
      if ([self.incident objectForKey:@"eventDate"] == (id)[NSNull null]) {
                        self.labelEventDate.text = @"This is a test";

                    }
agreatdaytocode
agreatdaytocode
24,757 Points
agreatdaytocode
agreatdaytocode
24,757 Points

Marcus shoot me an email I'll share it with you via GitHub.