NSMutableArray removeObjectAtIndex

Question

I'm getting the following error when removing from my NSMutableArray

-[__NSArrayI removeObjectAtIndex:]: unrecognized selector sent to instance 0x1cdced10
2011-07-13 00:33:14.333 MassText[1726:707] *** Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: '-[__NSArrayI removeObjectAtIndex:]: unrecognized selector sent to instance 0x1cdced10'

However right before I remove, I print out the array and the index. Neither are nil and I have no reason to believe why this error would be happening. Any ideas?

Answer 1

I had this problem. Mine was that I accidentally used type casting like this.

NSMutablearray * myarray = [[NSMutableArray alloc] init];
myarray =(NSMutableArray*) [mydictionary allkeys];

This will work for some time.. but if you are in a tight and large loop this tend to fail.

I changed my code to

NSMutableArray * myarray= [[NSMutablearray alloc] initWithArray:[mydictionary allKeys]];

Answer 2

The object is an NSArray, not an NSMutableArray.