CODEWITHSUNDEEP
jsonxcodecore-datafloating-pointnsdictionary
user3211165
user3211165

Reputation: 235

Getting a float from NSMutableDictionary with JSON

I have a core data model and a database built in JSON format. I send web request to the database and then I create a new object in the core data model with the values extracted. Strings work fine, but I am having a problem with extracting the float number. I cannot make it work properly. 

  float score;

      NSData *returnData = [NSURLConnection sendSynchronousRequest:request returningResponse:&response error:&requestError];

    NSMutableDictionary *prodData = [NSJSONSerialization
                                                JSONObjectWithData:returnData
                                                options:kNilOptions
                                                error:&error];
    TempClass* tempClass= [NSEntityDescription
                                   insertNewObjectForEntityForName:@"TempCode"
                                   inManagedObjectContext:context];

    tempClass.score = [[prodData valueForKey:@"score"] floatValue];

Error:

   * thread #1: tid = 0x92b05, 0x01b270b0 libobjc.A.dylib`objc_msgSend + 12, queue = 'com.apple.main-thread', stop reason = EXC_BAD_ACCESS (code=1, address=0x40600000)

Already tried:

 tempClass.score = prodData[@"score"];

and

float scoret = [[prodData valueForKey:@"score"] floatValue];
tempClass.score = &(scoret) ;

Upvotes: 0

Views: 93

Answers (2)

user3211165
user3211165

Reputation: 235

Fixed the EXC_BAD_ACCESS, by converting the float to NSNumber. Then logging NSNumber on float format.

Upvotes: 0

Ajith Renjala
Ajith Renjala

Reputation: 5162

Assigning to (float*) from incompatible type float

This implies that you have declared 'score' as an instance of 'float'. i.e as float *score; Remove the '*' please. float is a primitive data type.

Its also a good practise to cast the serialised JSON data (just to be on the safer side). 

id _castIf(Class requiredClass, id object) {
  if (object && ![object isKindOfClass:requiredClass])
    object = nil;
  return object;
}

And can be used as:

_castIf(NSNumber,prodData[@"score"]);

Updated:

EXC_BAD_ACCESS errors occur mostly in scenarios like:

  • Trying to access an object that is not initialized.
  • Trying to access an object that no longer exists. Either it’s being released or it’s nil. In ARC mode, make sure you take ownership(strong) of the object that you want to use.
  • Passing an message to an object that the object doesn’t understand. It can also happen for bad typecast.

Some ways to debug this is by going backwards on your stack of backtrace, using NSZombies, perhaps a good browse through web might also help; there are lots of resources already.

Upvotes: 1

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