NSMutableArray key value coding error

Question

Looking for help diagnosing the following error:

* Terminating app due to uncaught exception 'NSUnknownKeyException', reason: '[<__NSCFBoolean 0x39d40da8> setValue:forUndefinedKey:]: this class is not key value coding-compliant for the key Cricket.'

Here's the code:

NSMutableArray *soundNames = [[NSMutableArray alloc] initWithObjects:@"Random", @"Cricket", @"Mosquito", @"Fly", @"Owl", @"Scratching", @"Whistle", nil];

NSNumber *noObj = [NSNumber numberWithBool:NO];
NSMutableArray *soundValues = [[NSMutableArray alloc] initWithObjects:noObj, noObj, noObj, noObj, noObj, noObj, noObj, nil];

NSMutableDictionary *soundDict = [[NSMutableDictionary alloc]initWithObjectsAndKeys:soundNames, @"Sound Names", soundValues, @"Sound Values", nil]];

- (void)setSoundDictValue:(BOOL)value forKey:(NSString *)key
{
    [[soundDict objectForKey:@"Sound Values"] setValue:[NSNumber numberWithBool:value] forKey:key];
    …
}

Thanks Tony.

Answer 1

You are building the dictionary incorrectly. Why not just do:

NSMutableDictionary *soundDict = [@{
    @"Random" : @NO,
    @"Cricket" : @NO,
    @"Mosquito" : @NO,
    @"Fly" : @NO,
    @"Owl" : @NO,
    @"Scratching" : @NO,
    @"Whistle" : @NO
} mutableCopy];

Then your setSoundDictValue:forKey: method becomes:

- (void)setSoundDictValue:(BOOL)value forKey:(NSString *)key {
    sound[key] = @(value);
}

The problem with your code is easier to see if you split it up:

- (void)setSoundDictValue:(BOOL)value forKey:(NSString *)key {
    NSArray *sounds = [soundDict objectForKey:@"Sound Values"];
    [sounds setValue:[NSNumber numberWithBool:value] forKey:key];
}

As you can see, you try to call setValue:forKey: on an NSArray.

Answer 2

When you call setValue:forKey on an array, it invokes setValue:forKey on each object in that array (see https://developer.apple.com/library/mac/#documentation/Cocoa/Reference/Foundation/Classes/NSArray_Class/NSArray.html). [soundDict objectForKey:@"Sound Values"] is the same as soundValues, which is an array of NSNumbers. NSNumber does not have a property named Crickit. What exactly are you trying to do?