CODEWITHSUNDEEP
objective-cioscocoa-touch
ORStudios
ORStudios

Reputation: 3233

NSNull isEqualToString Issue With JSON Response

I am getting the following error

-[NSNull isEqualToString:]: unrecognized selector sent to instance 0x3c168090

on this line of code

cell.offerTitle.text = [voucherData objectForKey:@"offer_title"];

Could someone help me correct the problem please?

Thanks Oliver

Upvotes: 1

Views: 1662

Answers (4)

Alex
Alex

Reputation: 2150

i make some changing for noa's answer

-(NSDictionary*)safeData:(NSDictionary*)dict{
    NSMutableDictionary *dictionary = [NSMutableDictionary dictionaryWithDictionary:dict];
    NSArray *keys = dictionary.allKeys;
    for (int i = 0; i < keys.count; i++){
        id value = [dictionary objectForKey:[keys objectAtIndex:i]];
        // you can add recursive here
        value = [value isKindOfClass:[NSNull class]] ? @"" : value;
        [dictionary setObject:value forKey:[keys objectAtIndex:i]];
}
    return dictionary; }

and use 

dictionary = [self safeData:dictionary];

Upvotes: 0

matt
matt

Reputation: 535229

One candidate for best practice here is to use isEqual:, not isEqualToString:. That way, if what you get is not a string, you won't get an error and the equality test will be failed in good order.

On the other hand you could argue that isEqualToString: was a good choice, because when what you got was not a string, you got an error that alerted you to the issue!

EDIT: But that's wrong; see the comments below. The isEqualToString: message is coming from UIKit, not from the OP's own code.

Upvotes: 0

paulmelnikow
paulmelnikow

Reputation: 17208

Is voucherData an NSDictionary?

It's possible there's an NSNull in your dictionary, and when the dictionary is trying to find the object for offer_title, it's running into trouble.

Another possibility is that [voucherData objectForKey:@"offer_title"] is returning [NSNull null], and the label is barfing when you try to pass that instead of a string.

Try setting a breakpoint in objc_exception_throw and read the stack trace – that will give you a much better idea of what's going on.

Added:

id value = [voucherData objectForKey:@"offer_title"];
if ([value isKindOfClass:[NSNull class]])
    cell.offerTitle.text = @"";
else
    call.offerTitle.text = value;

or

id value = [voucherData objectForKey:@"offer_title"];
cell.offerTitle.text = [value isKindOfClass:[NSNull class]] ? @"" : value;

Upvotes: 6

Michael Dautermann
Michael Dautermann

Reputation: 89509

What that line from the console is likely telling you is that "voucherData" is not the "NSDictionary" object that you assume that it is.

Also make sure that "offerTitle" in your cell is a valid UITextField as well.

Upvotes: -1

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