NSCFArray append string errors, distinct Objective-C types
Ran into some weirdness earlier which was absolutely killing me. I’m building a project using SQLite Persistent Objects, and this:
NSMutableDictionary *dict = [[NSMutableDictionary alloc] init]; dict = [Commands sortedFieldValuesWithKeysForProperty:@"commandname"]; self.keyLookup = [dict mutableDeepCopy]; NSMutableArray *array = [[NSMutableArray alloc] init]; array = [[[self.keyLookup allValues] sortedArrayUsingSelector:@selector(compare:)] retain];
was throwing an error about assigning the values from a distinct Objective-C type. I was able to fake my way around it in another viewController I had a similar issue with, but this time it was a show stopper because when I tried to work with the resulting array later (by adding/removing some stuff from it) I would get another error:
exception: *** -[NSCFArray addObject:]: mutating method sent to immutable object
Well, I was pretty dammed sure I hadn’t asked for my array to be immutable, but I’m guessing somewhere in the code for the persistent object (which I’ll be checking into) there’s a copy happening (or something similar) and its turning the returned data into an NSCFArray. To fix it… I needed to make it a mutable array again:
if (self.commandArray != array){
[self.commandArray release];
self.commandArray = [array mutableCopy];
Of course this may be simple if you’re the programming type… but it drove me nuts for a while!
