iOS NSDictionary value determine if Boolean from JSON boolean

Question

I have a JSON response from a web server that looks like this:

{"success":true, "token":"123456"}

and I want to use that in an if statement, and compare it with "YES".

However, doing this doesn't work:

NSDictionary *response = [response JSONValue]; // the JSON value from webservice response, converted to NSDictionary

if ([response objectForKey:@"success"]){} // does not work
if ([response objectForKey:@"success"] == YES){} // does not work
if ([[response objectForKey:@"success"] integerValue] == YES) {} // does not work...erroneous probably

How can I work around this? Typecasting in Boolean yields a warning too

the question was tagged sbjson. I am using the ios library SBJSON stig.github.com/json-framework — yretuta
– yretuta, Commented Nov 25, 2011 at 8:19

Community · Accepted Answer · 2017-05-23 11:46:50Z

61

since [response objectForKey:@"success"] does not work, what happens when you try [response valueForKey: @"success"]?

I suspect it returns a NSNumber and then you can do something like:

NSNumber * isSuccessNumber = (NSNumber *)[response objectForKey: @"success"];
if([isSuccessNumber boolValue] == YES)
{
    // this is the YES case
} else {
    // we end up here in the NO case **OR** if isSuccessNumber is nil
}

Also, what does NSLog( @"response dictionary is %@", response ); look like in your Console? I see the JSON library you're using does return NSNumber types for objectForKey, so I suspect you might not have a valid NSDictionary.

edited May 23, 2017 at 11:46

CommunityBot

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answered Nov 25, 2011 at 8:21

Michael Dautermann

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3 Comments

Koen. Over a year ago

You're missing the @ symbol before the first argument of NSLog

Aaron Brager Over a year ago

You may want to actually test the type instead of doing a simple cast, or put this code in a try/catch block. Otherwise, if the JSON changes, you may accidentally send boolValue to an NSString (which will return YES for "Y", "y", "T", "t", or a digit 1-9), or a collection object, which will throw an exception.

hkaraoglu Over a year ago

this solution is not effective and is long. the short answer is if([response objectForKey: @"success"] boolValue])

Scott D · Accepted Answer · 2013-05-07 18:29:15Z

11

An alternative approach to this, which requires no conversion to NSNumber is something like below:

if ([response objectForKey:@"success"])
{
    if ([[response objectForKey:@"success"] boolValue])
        NSLog(@"value is true");
}

answered May 7, 2013 at 18:29

Scott D

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