ios - Parsing summary from RSS Feed causes app to crash -

i trying add summary uitableview parsing rss feed. have set method summary, app crashing. victim line is:

[item setobject:summary forkey:@"summary"]; 

crash code:

2014-05-17 09:32:09.231 ***[1169:90b] *** terminating app due uncaught exception 'nsinvalidargumentexception', reason: '*** setobjectforkey: object cannot nil (key: summary)' *** first throw call stack: (     0   corefoundation                      0x0453a1e4 __exceptionpreprocess + 180     1   libobjc.a.dylib                     0x037bd8e5 objc_exception_throw + 44     2   corefoundation                      0x045c3eb8 -[__nsdictionarym setobject:forkey:] + 888     3   ***                                 0x0010367a -[*** parser:didendelement:namespaceuri:qualifiedname:] + 394     4   foundation                          0x034ac991 _endelementns + 363     5   libxml2.2.dylib                     0x00626788 xmlparseendtag2 + 744     6   libxml2.2.dylib                     0x00628bf8 xmlparsetryorfinish + 3347     7   libxml2.2.dylib                     0x00627cfa xmlparsechunk + 886     8   foundation                          0x034aa8fb -[nsxmlparser parsedata:] + 329     9   foundation                          0x034aac17 -[nsxmlparser parsedata:] + 1125     10  foundation                          0x034aadf1 -[nsxmlparser parsefromstream] + 287 

main code:

 - (void)parser:(nsxmlparser *)parser didendelement:(nsstring *)elementname namespaceuri:(nsstring *)namespaceuri qualifiedname:(nsstring *)qname {          if ([elementname isequaltostring:@"item"]) {              [item setobject:title forkey:@"title"];             [item setobject:link forkey:@"link"];     [item setobject:summary forkey:@"summary"];             [feeds addobject:[item copy]];          }      }     - (void)parser:(nsxmlparser *)parser didstartelement:(nsstring *)elementname namespaceuri:(nsstring *)namespaceuri qualifiedname:(nsstring *)qname attributes:(nsdictionary *)attributedict {      element = elementname;      if ([element isequaltostring:@"item"]) {          item    = [[nsmutabledictionary alloc] init];         title   = [[nsmutablestring alloc] init];         link    = [[nsmutablestring alloc] init]; summary = [[nsmutablestring alloc] init];      }  }     - (void)parser:(nsxmlparser *)parser foundcharacters:(nsstring *)string {          if ([element isequaltostring:@"title"]) {             [title appendstring:string];         } else if ([element isequaltostring:@"link"]) {             [link appendstring:string];         }else if ([element isequaltostring:@"summary"]) {             [summary appendstring:string];         }      } 

what's issue?? can understand code saying there nil returning, should put instead of summary??

cheers, seboh

your problem lies in didstartelement method. when detect item need initialise summary empty nsstring @"" - otherwise nil , keep calling appendstring on nil resulting in nil value.

it should

- (void)parser:(nsxmlparser *)parser didstartelement:(nsstring *)elementname namespaceuri:(nsstring *)namespaceuri qualifiedname:(nsstring *)qname attributes:(nsdictionary *)attributedict {      element = elementname;      if ([element isequaltostring:@"item"]) {          item    = [[nsmutabledictionary alloc] init];         title   = [[nsmutablestring alloc] init];         link    = [[nsmutablestring alloc] init];         summary = [[nsmutablestring alloc] init];      } }