Checking a null value in Objective-C that has been returned from a JSON string

Question

I have a JSON object that is coming from a webserver.

The log is something like this:

{          
   \"status\":\"success\",
   \"Us         


        

Answer 1

if([tel isEqual:[NSNull null]])
{
   //do something when value is null
}

Answer 2

Here you can also do that by checking the length of the string i.e.

if(tel.length==0)
{
    //do some logic here
}

Answer 3

Try this:

if (tel == (NSString *)[NSNull null] || tel.length==0)
{
    // do logic here
}

Answer 4

I use this:

#define NULL_TO_NIL(obj) ({ __typeof__ (obj) __obj = (obj); __obj == [NSNull null] ? nil : obj; }) 

Answer 5

if we are getting null value like then we can check it with below code snippet.

 if(![[dictTripData objectForKey:@"mob_no"] isKindOfClass:[NSNull class]])
      strPsngrMobileNo = [dictTripData objectForKey:@"mobile_number"];
  else
           strPsngrMobileNo = @"";

Answer 6

I usually do it like this:

Assuma I have a data model for the user, and it has an NSString property called email, fetched from a JSON dict. If the email field is used inside the application, converting it to empty string prevents possible crashes:

- (id)initWithJSONDictionary:(NSDictionary *)dictionary{

    //Initializer, other properties etc...

    id usersmail = [[dictionary objectForKey:@"email"] copy];
    _email = ( usersmail && usersmail != (id)[NSNull null] )? [usersmail copy] : [[NSString      alloc]initWithString:@""];
}