Question

This code is causing the error, what could be wrong ?
I read something about locks, and that immutable objects can be susceptible to crashing when used on multiple threads. But really I do not know what that is all about…

-(void)cleanUpAllHexagons{

    //Cleaning up all hexagons from previous level
    NSLog(@"cleaning hexagons");
    NSString *spriteKey;
    NSString *touchAreaKey;

    NSMutableDictionary *existingHexagons = [[GameStateSingleton sharedMySingleton]getExistingHexagons];

        for (int i= 0; i < [existingHexagons count]; i++){
            spriteKey = [NSString stringWithFormat:@"hexagon%d",i];

            for (spriteKey in existingHexagons) {
                NSLog(@"the spritekey = %@",spriteKey);
                NSLog(@"%@", existingHexagons);
                NSLog(@"%@", [[existingHexagons valueForKey:spriteKey]objectForKey:@"realSprite"]);
                [self removeChild:[[existingHexagons valueForKey:spriteKey]objectForKey:@"realSprite"] cleanup:YES];
                [existingHexagons removeObjectForKey:spriteKey];
            } 


            hexTouchAreas = [[GameStateSingleton sharedMySingleton]getSharedHexTouchAreas];

            touchAreaKey = [NSString stringWithFormat:@"hexTouchArea%d",i];

            for (touchAreaKey in hexTouchAreas) {
                NSLog(@"the touchAreakey = %@",touchAreaKey);
                NSLog(@"%@", [hexTouchAreas valueForKey:touchAreaKey]);
                [self removeChild: [hexTouchAreas valueForKey:touchAreaKey] cleanup:YES];
            } 

        }  


}

Answer 1

To enumerate all keys in this situation, you can use

for (spriteKey in [existingHexagons allKeys])

So you can modify the dictionary while enumerating. However, If you are going to remove all keys anyway, shouldn’t you empty the dictionary after the loop using removeAllObjects method instead?