Error setting value of NSMutableDictionary - ios

Question

I initialize this NSMutableDictionary:
define TAREFA #"TAREFA"
define DATA_ITEM #"DATA"
define HORA_ITEM #"HORAS"
define ID #"ID"
define STATE #"NA"
define APROVED #"APROVED"
define REJECTED #"REJECTED"
itensArray = [[NSMutableArray alloc] init];
for (int i=0; i< [listagens size]; i++)
{
NSMutableDictionary *tmpDictionary = [[NSMutableDictionary alloc] initWithObjectsAndKeys:
[[listagens item:i] WI_ID], ID,
[[listagens item:i] WI_TEXT], TAREFA,
[[listagens item:i] WI_CD], DATA_ITEM,
[[listagens item:i] WI_CT], HORA_ITEM,
STATE, STATE,
nil];
[itensArray addObject:tmpDictionary];
}
Later on, i do the following:
for (int i=0; i<[itensArray count]; i++)
{
if ([[[itensArray objectAtIndex:i] objectForKey:ID] isEqualToString:cell.idLabel.text]) {
[[itensArray objectAtIndex:i] setString:APROVED forKey:STATE];
break;
}
}
I initialize the array, then later on, i change a string of the NSMutableDictionary. When i set the value i get the following runtime error:
'NSInvalidArgumentException', reason: '-[__NSCFDictionary
setString:forKey:]: unrecognized selector sent to instance 0x7b7d170'
It appears i´m not changing the value correctly. Is it a syntax error? How is it done?

Answer 1

maybe you misspelled the name of the method.
// WRONG
[[itensArray objectAtIndex:i] setString:APROVED forKey:STATE];
// GOOD
[[itensArray objectAtIndex:i] setValue:APROVED forKey:STATE];

Answer 2

'NSInvalidArgumentException', reason: '-[__NSCFDictionary setString:forKey:]: unrecognized selector sent to instance 0x7b7d170'
NSMutableDictionary has no setString:forKey: method.
Try setObject:forKey:
[[itensArray objectAtIndex:i] setObject:APROVED forKey:STATE];