How do I parse JSON with Objective-C

Question

I am new to iPhone  Can anyone tell me the steps to follow to parse this data and get the activity details  first name  and last name           error   false         data                                activity id    35336                 user id    1                 user first name    Chandra Bhusan                 user last name    Pandey                 time    1300870420                 activity details    Good n                 activity type    status update                 photo url    http   184 73 155 44 hcl-meme QA TEST sites default files pictures picture-1627435117 jpg                       boolean    1             1                  1                      photo 1 id    9755                               activity id    35294                 album name    Kalai new Gallery                 user id    31                 album id    9754                 user first name    Kalaiyarasan                 user last name    Balu                 0                      photo 0 id    9756                               time    1300365758                 activity type    photo upload                 photo url    http   184 73 155 44 hcl-meme QA TEST                        3                  activity id    35289                 user id    33                 user first name    Girija                 user last name    S                 time    1300279636                 activity details    girija Again n                 activity type    status update                 photo url    http   184 73 155 44 hcl-meme QA TEST sites default files pictures picture-33-6361851323080768 jpg                       2                  owner first name    Girija                 activity id    35290                 activity details    a 2  s 4   html   s 51    user fullname and  friend fullname are now friends   s 4   type   s 10   friend add                     activity type    friend accept                 owner last name    S                 time    1300280400                 photo url    http   184 73 155 44 hcl-meme QA TEST sites default files pictures picture-33-6361851323080768 jpg                 owner id    33                       4                  activity id    35288                 user id    33                 user first name    Girija                 user last name    S                 time    1300279530                 activity details    girija from mobile n                 activity type    status update                 photo url    http   184 73 155 44 hcl-meme QA TEST sites default files pictures picture-33-6361851323080768 jpg

User · Answer

JSON parsing using NSJSONSerialization

   NSString* path  = [[NSBundle mainBundle] pathForResource:@"data" ofType:@"json"];
   
    //Here you can take JSON string from your URL ,I am using json file
    NSString* jsonString = [[NSString alloc] initWithContentsOfFile:path encoding:NSUTF8StringEncoding error:nil];
    NSData* jsonData = [jsonString dataUsingEncoding:NSUTF8StringEncoding];
    NSError *jsonError;
    NSArray *jsonDataArray = [NSJSONSerialization JSONObjectWithData:[jsonString dataUsingEncoding:NSUTF8StringEncoding] options:kNilOptions error:&jsonError];
  
    NSLog(@"jsonDataArray: %@",jsonDataArray);

    NSDictionary *jsonObject = [NSJSONSerialization JSONObjectWithData:jsonData options:kNilOptions error:&jsonError];
if(jsonObject !=nil){
   // NSString *errorCode=[NSMutableString stringWithFormat:@"%@",[jsonObject objectForKey:@"response"]];
   
        
        if(![[jsonObject objectForKey:@"#data"] isEqual:@""]){
            
            NSMutableArray *array=[jsonObject objectForKey:@"#data"];
             // NSLog(@"array: %@",array);
            NSLog(@"array: %d",array.count);  
            
            int k = 0;
            for(int z = 0; z<array.count;z++){
                
                NSString *strfd = [NSString stringWithFormat:@"%d",k];
                NSDictionary *dicr = jsonObject[@"#data"][strfd];
                k=k+1;
                // NSLog(@"dicr: %@",dicr);
                 NSLog(@"Firstname - Lastname   : %@ - %@",
                     [NSMutableString stringWithFormat:@"%@",[dicr objectForKey:@"user_first_name"]],
                     [NSMutableString stringWithFormat:@"%@",[dicr objectForKey:@"user_last_name"]]);
            }
            
          }

     }

You can see the Console output as below :

Firstname - Lastname : Chandra Bhusan - Pandey

Firstname - Lastname : Kalaiyarasan - Balu

Firstname - Lastname : (null) - (null)

Firstname - Lastname : Girija - S

Firstname - Lastname : Girija - S

Firstname - Lastname : (null) - (null)

User · Answer

With the perspective of the OS X v10 7 and iOS 5 launches  probably the first thing to recommend now is NSJSONSerialization  Apple s supplied JSON parser  Use third-party options only as a fallback if you find that class unavailable at runtime   So  for example   NSData  returnedData      JSON data  probably from a web request        probably check here that returnedData isn t nil  attempting    NSJSONSerialization with nil data raises an exception  and who    knows how your third-party library intends to react   if NSClassFromString   NSJSONSerialization          NSError  error   nil      id object    NSJSONSerialization                       JSONObjectWithData returnedData                       options 0                       error  amp error        if error       JSON was malformed  act appropriately here              the originating poster wants to deal with dictionaries         assuming you do too then something like this is the first        validation step      if  object isKindOfClass  NSDictionary class                  NSDictionary  results   object             proceed with results as you like  the assignment to         an explicit NSDictionary   is artificial step to get          compile-time checking from here on down  and better autocompletion         when editing   You could have just made object an NSDictionary           in the first place but stylistically you might prefer to keep         the question of type open until it s confirmed              else                  there s no guarantee that the outermost object in a JSON         packet will be a dictionary  if we get here then it wasn t          so  object  shouldn t be treated as an NSDictionary  probably         you need to report a suitable error condition            else          the user is using iOS 4  we ll need to use a third-party solution         If you don t intend to support iOS 4 then get rid of this entire        conditional and just jump straight to        NSError  error   nil          NSJSONSerialization JSONObjectWithData

User · Answer

Don t reinvent the wheel  Use json-framework or something similar    If you do decide to use json-framework  here s how you would parse a JSON string into an NSDictionary   SBJsonParser  parser      SBJsonParser alloc  init  autorelease      assuming jsonString is your JSON string    NSDictionary  myDict    parser objectWithString jsonString       now you can grab data out of the dictionary using objectForKey or another dictionary method

User · Answer

NSString  path      NSBundle mainBundle  pathForResource   index  ofType   json                        NSUTF8StringEncoding       NSString  jsonString     NSString alloc  initWithContentsOfFile path encoding NSUTF8StringEncoding error nil                 NSData  jsonData    jsonString dataUsingEncoding NSUTF8StringEncoding    NSError  jsonError  id allKeys    NSJSONSerialization JSONObjectWithData jsonData options NSJSONWritingPrettyPrinted error  amp jsonError     for  int i 0  i lt  allKeys count   i          NSDictionary  arrayResult    allKeys objectAtIndex i       NSLog   name      arrayResult objectForKey   storyboardName          file             ID  1     idSort    0     deleted  0     storyboardName     MLMember      dispalyTitle     76 360779      rightLevel     10 010490      showTabBar    1     openWeb    0     webUrl                 ID  1     idSort    0     deleted  0     storyboardName     0 00      dispalyTitle     76 360779      rightLevel     10 010490      showTabBar    1     openWeb    0     webUrl

User · Answer

I recommend and use TouchJSON for parsing JSON  To answer your comment to Alex  Here s quick code that should allow you to get the fields like activity details  last name  etc  from the json dictionary that is returned   NSDictionary  userinfo  jsondic valueforKey    data    NSDictionary  user  NSInteger i   0  NSString  skey  if userinfo    nil       for  i   0  i  lt   userinfo count   i               if i              skey    NSString stringWithFormat    d  i           else             skey                 user    userinfo objectForKey skey           NSLog   activity details      user objectForKey   activity details             NSLog   last name      user objectForKey   last name             NSLog   first name      user objectForKey   first name             NSLog   photo url      user objectForKey   photo url

[objective-c] How do I parse JSON with Objective-C?

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