ios - iphone: [NSNull getCharacters:]: unrecognized selector error using NSPredicate

Question

Hi when I try to search an entity in core data on certain fields, I get the following error:

[NSNull getCharacters:]: unrecognized selector sent to instance

This is code I am using to set predicate:

- (void)filterContentForSearchText:(NSString*)searchText scope:(NSString*)scope
{
    NSPredicate *resultPredicate =[NSPredicate predicateWithFormat:@"jobtitle=%@",@"Barber"];
    searchResults = [getContacts filteredArrayUsingPredicate:resultPredicate];
}

However, when I set the predicate to something I know is true on other fields, the search works correctly:

- (void)filterContentForSearchText:(NSString*)searchText scope:(NSString*)scope
{
    NSPredicate *resultPredicate =[NSPredicate predicateWithFormat:@"title=%@",@"Dr"];
    searchResults = [getContacts filteredArrayUsingPredicate:resultPredicate];
}

First version searches on title field/attribute, second on jobtitle field/attribute.

Examining the attributes job and jobtitle in the model, I cannot discern any difference between them.

Can anyone tell me where the NSNull is coming from and what it means? Could there be something I am missing in the properties of the attributes that would account for this?

Thanks in advance for any suggestions.

Answer 1

Looks like objects in getContacts array don't have jobtitle property in first method. You can check it by printing the first object NSLog(@"%@", getContacts.firstObject) or print the whole array NSLog(@"%@", getContacts)