[davecom]

I have an NSMutableArray which is initialized as follows:
NSMutableArray *array; //in header file
array = [NSMutableArray array]; //in applicationWillFinishLaunching

and then it gets this error message later on in another method:
Aug 04 17:02:01 Zipper[463] *** -[NSCFString addObject:]: selector not recognized
Aug 04 17:02:01 Zipper[463] *** -[NSCFString addObject:]: selector not recognized

when this code runs
[array addObject:aFile]; //aFile is a plain NSString

What's causing the error message?

[amonitzer]

Don't use [NSMutableArray array]. Use:

<BLOCKQUOTE><font size="1"face="Geneva, Verdana, Arial">code:</font><HR><pre><font size=1 face=courier>
- (<font color = purple>id</font>)init {
<font color = green>if</font>(<font color = purple>self</font>=[<font color = purple>super</font> init]) {
array=[[NSMutableArray alloc] init];
}
<font color = green>return</font> <font color = purple>self</font>;
}
- (<font color = green>void</font>)dealloc {
[array release];
}
</font>[/code]

[NSMutableArray array] adds the object to the autorelease pool, which means that it will get deallocated earlier than you expected.

[lindberg]

Right, if you want to have the array as an ivar you need to hold a retain on it, and release it in -dealloc, making sure it stays around while your instance stays around. Just change [NSMutableArray array] to [[NSMutableArray array] retain] or [[NSMutableArray alloc] init] (the +alloc implies a retain count of 1).

And when you override -dealloc, make sure to call [super dealloc] at the end ;-)

In the current code, just so you know why that particular error message happened, the array was autoreleased immediately, which means it was dealloced at the end of the event. You still had a pointer to it, but the memory was freed, and an NSString just so happened to be allocated in that spot in memory. If you see methods being sent to the utterly wrong class, this is virtually always the reason why it happens. If there was some other random memory that was allocated there, you would have gotten a segfault or bus error.

[davecom]

Thanks, as usual, for all the help. Progress continues...

[amonitzer]

Originally posted by lindberg:
<STRONG>And when you override -dealloc, make sure to call [super dealloc] at the end ;-)</STRONG>

Oops. I tend to forget to call super. I think I have to check my latest code for that bug...
Thanks!