Question

I have a NSMutableArray allAnswers

NSMutableArray *allAnswers = [[NSMutableArray alloc] init];

With the values :

allAnswers --- (
        {
        PlayerName = Trfghuhhrf;
        Score = 1000;
    },
        {
        PlayerName = Test;
        Score = 333;
    },
        {
        PlayerName = DDDDDDDD;
        Score = 250;
    },
        {
        PlayerName = SSSSSSSSSSSSSSS;
        Score = 100;
    },
        {
        PlayerName = mn;
        Score = 100;
    }
)

This is how I am building dictionary.

    NSDictionary *answer = [NSDictionary dictionaryWithObjectsAndKeys:
                            name, PlayerKey,
                            [NSNumber numberWithInt:[score intValue]], ScoreKey,
                            nil];
    [allAnswers addObject:answer];


NSSortDescriptor *sortDesc = [NSSortDescriptor sortDescriptorWithKey:ScoreKey ascending:NO];

[allAnswers sortUsingDescriptors:[NSArray arrayWithObject:sortDesc]];

NSLog(@"allAnswers --- %@",allAnswers);

for (NSDictionary *answer in allAnswers)
{
    NSLog(@"%@, %@", [answer objectForKey:PlayerKey], [answer objectForKey:ScoreKey]);

    NSMutableString *mString = [[NSMutableString alloc]init];
    [mString appendString:[answer objectForKey:PlayerKey]];
    [mString appendString:@" - "];
    [mString appendString:[answer objectForKey:ScoreKey]];

    NSLog(@"mString --******-- %@",mString);
}

App is crahsing when I am trying to add [answer objectForKey:ScoreKey] to mutable string. I tried converting [answer objectForKey:ScoreKey] to (NSString) but that did’t help.

Please advise what I am doing wrong.

Sorry for long description.

Adding Crash logs :

---

2012-03-03 00:43:48.149 NumberTwins[38378:10703] -[__NSCFNumber length]: unrecognized selector sent to instance 0x9155400
2012-03-03 00:43:48.149 NumberTwins[38378:10703] * Terminating app due to uncaught exception ‘NSInvalidArgumentException’, reason: ‘-[__NSCFNumber length]: unrecognized selector sent to instance 0x9155400’
* First throw call stack:

Answer 1

You are storing an int as an NSNumber for the key ScoreKey but you can’t just append this to a string, because it is the wrong type. You need to convert it to an NSString.

You can’t just cast the NSNumber to an NSString because its a different type altogether; you should use the correct method of NSNumber:

[mString appendString:[[answer objectForKey:ScoreKey] stringValue]];

The reason you are able to get a value logged is because putting a %@ in the log calls the object’s description method. This method is declared in NSObject, and the Framework classes implement it so that it returns a representation of the object as a string.