Question

i have a problem with Objective C code, i recieve these errors.

 2013-01-31 16:22:53.611 iSA-MP[541:c07] -[__NSCFDictionary objectAtIndex:]: unrecognized selector sent to instance 0x7465d70
2013-01-31 16:22:53.614 iSA-MP[541:c07] *** Terminating app due to uncaught exception               'NSInvalidArgumentException', reason: '-[__NSCFDictionary objectAtIndex:]: unrecognized selector sent to instance 0x7465d70'
*** First throw call stack:
(0x1c8c012 0x10c9e7e 0x1d174bd 0x1c7bbbc 0x1c7b94e 0x2163 0xf2817 0xf2882 0x41a25 0x41dbf             0x41f55 0x4af67 0xefcc 0xffab 0x21315 0x2224b 0x13cf8 0x1be7df9 0x1be7ad0 0x1c01bf5 0x1c01962 0x1c32bb6 0x1c31f44 0x1c31e1b 0xf7da 0x1165c 0x1dbd 0x1ce5) 
libc++abi.dylib: terminate called throwing an exception

with this code:

  NSString *urlString = [NSString stringWithFormat:@"http://192.168.0.125:100/isa-mp/iSA-MP.php?serverIP=192.168.0.125&serverPort=7777"];
NSURL *url = [NSURL URLWithString:urlString];
NSData *data = [NSData dataWithContentsOfURL:url];
NSError *error;
NSMutableArray *array = (NSMutableArray*)[NSJSONSerialization JSONObjectWithData:data options:kNilOptions error:&error];

NSLog(@"%@", [array objectAtIndex:0]);

Answer 1

You are being returned a Dictionary, if you don’t know the contents of your data you are recieved, NSLog [NSJSONSerialization JSONObjectWithData:data options:kNilOptions error:&error] and check the key for the item that you want to be array.

You might want to do something like this:

NSDictionary *dict = [NSJSONSerialization JSONObjectWithData:data options:kNilOptions error:&error];
NSMutableArray *array = dict[@"someKeyForArray"];