Question

I’m a total noob to iPhone programming, and I’ve run into an exception being thrown that I just can’t wrap my head around.

Background: The error is happening in a custom subview, and occurs immediately upon loading the program. I’m getting an exception thrown in the overridden drawRect method. The code throwing the error follows:

- (void)drawRect:(CGRect)rect{
    NSNumber *points = [NSNumber numberWithInt: star.numberOfPoints];
    //HERE. Doesn't recognize selector?!
    CGPathRef t = (CGPathRef)[starPaths objectForKey:points];
 /*snip*/

starPaths is initialized in awakeFromNib as an NSMutableDictionary with capacity 1.

The exception that’s getting thrown is -[NSObject doesNotRecognizeSelector:]

starPaths is declared in the header file for the view as

    NSMutableDictionary *starPaths;

and is initialized as

- (void)awakeFromNib{
    starPaths = [NSMutableDictionary dictionaryWithCapacity: 1];
} 

Finally, I haven’t been able to get to a point in the code where I successfully add elements to the dictionary, since the code to add an entry relies on receiving a nil response from the dictionary to know that the that specific entry needs to be built.

Any suggestions? Any other information I should provide?
Any help at all would be appreciated, I feel like I’m missing something obvious, but I’ve been bashing my head against this all day with no luck.

Answer 1

If you do not retain the starPaths variable or explicitly allocate it yourself with [[NSMutableDictionary alloc] initWithCapacity:1] then it will be automatically released on the next iteration of the run loop.

You need to do

starPaths = [[NSMutableDictionary dictionaryWithCapacity:1] retain];

Or

starPaths = [[NSMutableDictionary alloc] initWithCapacity:1];

Just make sure to release it when you no longer need it.