How to get a integer value from JSON data in iphone application

I am parisng data using following date which is in JSON

[
 {
     "categoryId": 202,
     "name": "Sport"
 },
 {
     "categoryId": 320,
     "name": "Fritid"
 },
 {
     "categoryId": 350,
     "name": "Kultur"
 },
 {
     "categoryId": 4920,
     "name": "Diverse"
 },
 {
     "categoryId": 4774,
     "name": "Samfunn"
 } ]

Using Follwing Code

SBJsonParser *parser = [[SBJsonParser alloc] init];

NSURLRequest *request = [NSURLRequest requestWithURL:[NSURL URLWithString:@"http://www.krsconnect.no/community/api.html?method=categories&appid=620&mainonly=true"]];
NSData *response = [NSURLConnection sendSynchronousRequest:request returningResponse:nil error:nil];
NSString *json_string = [[NSString alloc] initWithData:response encoding:NSUTF8StringEncoding];
NSDictionary *object = [parser objectWithString:json_string error:nil];
//appDelegate.books = [[NSMutableArray alloc] initWithCapacity:0];

appDelegate.books = [[NSMutableArray alloc] init];

NSArray *results = [parser objectWithString:json_string error:nil];
for (int i=0; i<[results count]; i++) {
    Book  *aBook = [[Book alloc] initWithDictionary:[results objectAtIndex:i]];
    [appDelegate.books addObject:aBook];


    [aBook release];

    }

Book C开发者_JAVA技巧lass

    @interface Book : NSObject {


NSString *catId;


NSString *name;

  }

     @property(nonatomic,retain)NSString*catId;

     @property(nonatomic,retain) NSString *name;

  @end


   #import "Book.h"


@implementation Book


@synthesize catId,name;

-(id)init{ 
    self=[super init];
}

- (id)initWithDictionary:(NSDictionary*) dict {
   self.catId = [dict valueForKey:@"categoryId"];   self.name = 
   [dict valueForKey:@"name"];
   return self;
}

that is because CatId is of tyoe NSString

Change it to NSNumber and try

Hope this helps.

It seems that you are getting NSNumber when you parse the response for categoryId. So try by taking NSNumber object inplace of NSString.

The dictionary you are getting stores numeric values as NSNumber objects probably. So your catId should either be a NSNumber too , or -initWithDictionary: should extract the category id into a primitive type using e.g. -intValue and catId should then be declared as int.

By the way, you should use -objectForKey: to get objects from NSDictionarys. It's marginally more performant since -valueForKey: does some extra processing, then calls -objectForKey:.

Also json_string leaks and so robably does appDelegate.books.