increment plist value

I'm trying to increment a value in a plist in objective-c (using cocos2d).

I'm loading data using this:

documentsDir = [NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES) objectAtIndex:0];
    NSString* filePath2 = [documentsDir stringByAppendingPathComponent:@"weaponchallenges.plist"];
    weaponChallengesList = [[NSMutableArray arrayWithContentsOfFile:filePath2] retain];

I believe this works as it is not erroring, although I'm not sure the best way to test this.

Inside the plist are various Dictionary items, within each items various keys + integers.

For example the first item in the plist has an item key 'kills' with an int value of 0.

I'm then using:

NSDictionary * weaponC = [weaponChallengesList obj开发者_StackOverflowectAtIndex:0];
        int killsTotal = [[weaponC valueForKey:@"kills"] intValue];
        [weaponC setValue:[NSNumber numberWithInt:(killsTotal + 1)] forKey:@"kills"];
        [weaponChallengesList replaceObjectAtIndex:0 withObject:weaponC];

But killsTotal always seems to be 0, any thoughts on what I could be doing incorrectly?

Check each step to see if the value is nil. Routines like arrayWithContentsOfFile: do not generate errors. They just return nil. So you'll wind up with weaponChallengesList is nil, weaponC is nil, killsTotal is 0, and your replaceObjectAtIndex:withObject: silently doing nothing.

In ObjC, if "nothing" seems to happen, then the #1 cause is that you're messaging nil.