ios - Parsing RSS in Obj-C? -

i'm trying parse rss date view in app, following this tutorial. have json file retrieve information , display on screen.

here's code

// //  viewcontroller.m //  jsonyt // //  created yo_291 on 3/16/15. //  copyright (c) 2015 yo_291. rights reserved. //  #import "viewcontroller.h"  @interface viewcontroller ()  {     nsmutabledata *webdata;     nsurlconnection *connection;     nsmutablearray *array; }  @end  @implementation viewcontroller    - (void)viewdidload {      [[self myview]setdelegate:self];      [[self myview]setdatasource:self];      array = [[nsmutablearray alloc]init];        [super viewdidload];     // additional setup after loading view, typically nib. }  - (void)didreceivememorywarning {     [super didreceivememorywarning];     // dispose of resources can recreated. }   -(void)connection:(nsurlconnection *)connection didreceiveresponse:(nsurlresponse *)response {     [webdata setlength:0]; }  -(void)connection:(nsurlconnection *)connection didreceivedata:(nsdata *)data {     [webdata appenddata:data]; }  -(void)connection:(nsurlconnection *)connection didfailwitherror:(nserror *)error {     nslog(@"fail error"); }  -(void)connectiondidfinishloading:(nsurlconnection *)connection  {     nsdictionary *alldatadictionary = [nsjsonserialization jsonobjectwithdata:webdata options:0 error:nil];     nsdictionary *rd = [alldatadictionary objectforkey:@"responsedata"];     nsdictionary *feed = [rd objectforkey:@"feed"];     nsarray *aoe = [feed objectforkey:@"entries"];      for(nsdictionary *diction in aoe)     {         nsdictionary *numb = [diction objectforkey:@"0"];         nsstring *title = [numb objectforkey:@"title"];           [array addobject:title];          }      [[self myview] reloaddata];   }   - (ibaction)getfeed:(id)sender {      nsurl *url = [nsurl urlwithstring:@"http://ajax.googleapis.com/ajax/services/feed/load?v=2.0&q=http://www.britannica.com/feeds/tdih.rss&num="];     nsurlrequest *request = [nsurlrequest requestwithurl:url];      connection = [nsurlconnection connectionwithrequest:request delegate:self];      if(connection)     {         webdata = [[nsmutabledata alloc]init];      }   }  -(nsinteger)numberofsectionsintableview:(uitableview *)tableview {     return 1; }  -(nsinteger)tableview:(uitableview *)tableview numberofrowsinsection:(nsinteger)section {     return [array count]; }  -(uitableviewcell *)tableview:(uitableview *)tableview cellforrowatindexpath:(nsindexpath *)indexpath {     static nsstring *celli = @"cell";     uitableviewcell *cell = [tableview dequeuereusablecellwithidentifier:celli];      if(!cell)     {         cell = [[uitableviewcell alloc]initwithstyle:uitableviewcellstyledefault reuseidentifier:celli];     }      cell.textlabel.text = [array objectatindex:indexpath.row];      return cell; }   @end 

the application crashes on line [array addobject:title];.

error stack trace:

2015-03-16 22:32:51.650 jsonyt[8195:547408] *** terminating app due uncaught exception 'nsinvalidargumentexception', reason: '*** -[__nsarraym insertobject:atindex:]: object cannot nil' *** first throw call stack: (     0   corefoundation                      0x000000010ba28a75 __exceptionpreprocess + 165     1   libobjc.a.dylib                     0x000000010b6c1bb7 objc_exception_throw + 45     2   corefoundation                      0x000000010b8f70ca -[__nsarraym insertobject:atindex:] + 954     3   jsonyt                              0x000000010b18da5f -[viewcontroller connectiondidfinishloading:] + 735     4   cfnetwork                           0x000000010d85998c __65-[nsurlconnectioninternal _withconnectionanddelegate:onlyactive:]_block_invoke + 69     5   cfnetwork                           0x000000010d859930 -[nsurlconnectioninternal _withconnectionanddelegate:onlyactive:] + 199     6   cfnetwork                           0x000000010d859a97 -[nsurlconnectioninternal _withactiveconnectionanddelegate:] + 48     7   cfnetwork                           0x000000010d729937 ___zn27urlconnectionclient_classic26_delegate_didfinishloadingeu13block_pointerfvve_block_invoke + 107     8   cfnetwork                           0x000000010d7f6a31 ___zn27urlconnectionclient_classic18_withdelegateasyncepkcu13block_pointerfvp16_cfurlconnectionpk33cfurlconnectionclientcurrent_vmaxe_block_invoke_2 + 273     9   cfnetwork                           0x000000010d714d16 _zn19runloopblockcontext13_invoke_blockepkvpv + 72     10  corefoundation                      0x000000010b930b44 cfarrayapplyfunction + 68     11  cfnetwork                           0x000000010d714bd7 _zn19runloopblockcontext7performev + 133     12  cfnetwork                           0x000000010d714a16 _zn17multiplexersource7performev + 256     13  cfnetwork                           0x000000010d71482c _zn17multiplexersource8_performepv + 72     14  corefoundation                      0x000000010b95dc91 __cfrunloop_is_calling_out_to_a_source0_perform_function__ + 17     15  corefoundation                      0x000000010b953b5d __cfrunloopdosources0 + 269     16  corefoundation                      0x000000010b953194 __cfrunlooprun + 868     17  corefoundation                      0x000000010b952bc6 cfrunlooprunspecific + 470     18  graphicsservices                    0x000000010f005a58 gseventrunmodal + 161     19  uikit                               0x000000010be18580 uiapplicationmain + 1282     20  jsonyt                              0x000000010b18e483 main + 115     21  libdyld.dylib                       0x000000010dfd6145 start + 1     22  ???                                 0x0000000000000001 0x0 + 1 ) libc++abi.dylib: terminating uncaught exception of type nsexception 

but have no idea how go fixing it. eyes i'm searching json file correctly may wrong. json file rss feed i've used google tool "turn" json database, i'm unsure if complications there.

let me know any/all information needed, first post don't know if i'm delivering enough context.

the error indicates object inserted nil. problem lies in following lines:

nsdictionary *numb = [diction objectforkey:@"0"]; nsstring *title = [numb objectforkey:@"title"]; [array addobject:title]; 

you never check whether title nil or not before adding object array. can use nslog() debug values , check nil values using techniques similar follow:

if([numb objectforkey:@"title"] != nil) {   [array addobject:[numb objectforkey:@"title"]]; } 

p.s. assigning value title useless, title used once (wasting memory).

also, using libraries afnetworking make codes simpler, , provides error handling.