Strange behaviour of NSString in NSView

Question

Trying to create a Skat-Game, I encountered the following problem:

isBidding is a Boolean value indicationg, the program is in a certain state, [desk selected] is a method calling returning the current selected player, chatStrings consists of dictionaries, saving strings with the player, who typed, and what he typed

- (void)drawRect:(NSRect)rect{

    NSMutableDictionary * attributes = [NSMutableDictionary dictionary];

    [attributes setObject:[NSFont fontWithName:playerFont size:playerFontSize] forKey:NSFontAttributeName];
    [attributes setObject:playerFontColor forKey:NSForegroundColorAttributeName];


    [[NSString stringWithFormat:@"Player %i",[desk selected] + 1] drawInRect:playerStringRect withAttributes:attributes];

    if (isBidding){
        [attributes setObject:[NSFont fontWithName:chatFont size:chatFontSize] forKey:NSFontAttributeName];
        [attributes setObject:chatFontColor forKey:NSForegroundColorAttributeName];

        int i;
        for (i = 0; i < [chatStrings count]; i++, yProgress -= 20){
            if (isBidding)
                [[NSString stringWithFormat:@"Player %i bids: %@",
                    [[[chatStrings objectAtIndex:i]valueForKey:@"Player"]intValue],
                    [[chatStrings objectAtIndex:i]valueForKey:@"String"]],
                        drawAtPoint:NSMakePoint([self bounds].origin.x, yProgress) withAttributes:attributes];   
            else
                [[NSString stringWithFormat:@"Player %i: %@",[[[chatStrings objectAtIndex:i] valueForKey:@"Player"]intValue],
                [[chatStrings objectAtIndex:i]valueForKey:@"String"]]
                    drawAtPoint:NSMakePoint([self bounds].origin.x, yProgress) withAttributes:attributes];

        }   
    }

    if (isBidding)
        [[NSString stringWithFormat:@"Player %i bids: %@",[desk selected] + 1, displayString]
            drawAtPoint:NSMakePoint([self bounds].origin.x, yProgress) withAttributes:attributes];
    else
        [[NSString stringWithFormat:@"Player %i: %@",[desk selected] + 1, displayString]
            drawAtPoint:NSMakePoint([self bounds].origin.x, yProgress) withAttributes:attributes];

    yProgress = chatFontBegin;
}

This is the part determining the string's content, the string is contributed by an [event characters] method.

-(void)displayChatString:(NSString *)string{
     displayString = [displayString stringByAppendingString:string];
     [self setNeedsDisplay:YES];
 }

The problem if have is this:

when typing in more than two letters the view displays NSRectSet{{{471, 574},{500, 192}}} and returns no more discription when I try to print it.

then I get an EXC_BAD_ACCESS message, though I have not released it (as far as I can see) I also created the string with alloc and init, so I cannot be in the autorelease pool. I also tried to watch the process when it changes with the debugger, but I couldn't find any responsible code.

As you can see I am still a beginner in Cocoa (and programming in general), so I would be really happy if somebody would help me with this.

Answer 1

I can't puzzle out your code but I can tell you something about the odd return.

NSRectSet is a private type inside the Foundation framework. You shouldn't ever see it. Its used internally IIRC to represent nested rectangles such as those of stacks of views.

You're either getting an odd memory problem that causes a string pointer to actually point at the NSRectSet or you've screwed up your method nesting and you're assigning the NSRectSet value to a string.