I am using if statement to check key is null or not but I can't understand what went wrong

Question

Here I am getting the Notification List null and it is causing me an exception. Here is my code:

if([[response.data valueForKey:@"NotificationList"] isEqual:@""] || [[response.data valueForKey:@"NotificationList"] isEqual:@"<null>"]) {

  NSLog(@"Data not available.!!!");

}
else
{
  NSLog(@"Data available.!!!");
}

@Pratik Prajapati can u elaborate what went wrong why am i not getting the output — Pankaj Chahakar, Oct 08 '18 at 06:14
try to check `response.data valueForKey:@"NotificationList"] != nil` and add your full source code — Pratik Prajapati, Oct 08 '18 at 06:16
this what i am getting in response.data....po response.data { NotificationList = ""; Status = "Data Not Exists."; StatusCode = 2; } — Pankaj Chahakar, Oct 08 '18 at 07:05
@ Pratik Prajapati i get value "null" in NotificationList key and i want to check if the value is null print error msg if it is not null execute the code — Pankaj Chahakar, Oct 08 '18 at 07:08

score 2 · Answer 1 · answered Oct 08 '18 at 09:48

When an object is printed or logged as "<null>", that does not mean it's a string object whose contents are <, n, u, l, l, and >. (Well, it doesn't usually mean that.)

Rather, "<null>" is how the singleton instance of NSNull describes itself.

So, the proper test is:

id notificationList = [response.data valueForKey:@"NotificationList"];
if (!notificationList || [notificationList isKindOfClass:[NSNull class]])
    NSLog(@"Data not available.!!!");

thank you guys it is working fine..thank you so much @Wileke — Pankaj Chahakar, Oct 09 '18 at 06:20

score 0 · Answer 2 · answered Oct 08 '18 at 09:22

You should just be able to check for the key returning a value...

if(!response.data[@"NotificationList"]) {

  NSLog(@"Data not available.!!!");

}
else
{
    NSLog(@"Data available.!!!");
}

https://stackoverflow.com/a/2784675/285190 - for more details

I am using if statement to check key is null or not but I can't understand what went wrong

2 Answers2