NSPopupButton displaying extra item when model changed

FROM : Johnny Lundy
DATE : Sat May 03 19:17:18 2008

Hello all,

Thanks for your previous help. I'm trying to firm up my understanding 
of NSPopupButton. I wrote a test project modeled after Kevin Wojniak's 
example here:

http://forums.macrumors.com/showthread.php?p=4839485  , post #7, 
referencing matt neuburg's example.

One NSPopupButton
One NSArrayController (popupController)
One NSObject (popup) whose Class is set to "Popup"

You know how everyone always says "All I am trying to do is..." ? 
Well, I just want to get the popup's selection in my Model so I can 
use the value in my code.

Bindings:
PopupButton bound to NSArrayController "popupController":
Content: popupController.arrangedObjects.type
Content Values: popupController.arrangedObjects.type
Selected Object: popup.selectedType

Bindings for popupController:
Content: popup.gameTypes

The little bit of code is below. Two classes, although I don't 
understand why Kevin made the second class (my class "GameType").

PROBLEM: The popup is loaded from the model array through the 
controller. No problem. When I call my "changeArray" method, though, 
the popup's display adds a fourth element, which isn't in the actual 
model array. The model object "selectedType" correctly updates when 
the popup's selection is changed.

- Do I need this extra class and this loop that populates the array 
"gameTypes?" It works, and just binding the controller to the 
"popupArray" by itself does not work. I don't get this.

- Is instantiating the NSObject "popup" in IB and setting its class to 
the class in which my ivars are declared the correct way to provide 
the controller layer with access to the Model layer?

Thanks


//Popup.h***************************
#import <Cocoa/Cocoa.h>
@interface Popup : NSObject
{
//Make an NSString instance variable and and two arrays for the popup
   NSMutableArray *gameTypes;
   NSArray *popupArray;
   NSString *selectedType;
}
- (void) changeArray;
@property (readwrite, copy) NSArray *popupArray;
@property (readwrite, retain) NSMutableArray *gameTypes;
@property (readwrite, copy) NSString *selectedType;
@end

//Popup.m*************************
#import "GameType.h"
@implementation Popup: NSObject
@synthesize popupArray, gameTypes, selectedType;
- (id) init
{
   self = [super init];
   return self;
}
- (void) awakeFromNib
{
   [self setPopupArray: [NSArray arrayWithObjects:@"C9", @"F11", 
@"Other", nil]];
   gameTypes = [NSMutableArray array];
   for (NSString *theType in popupArray)
   {
       GameType *gameTypeObject = [[[GameType alloc] init] autorelease];
       gameTypeObject.type = theType;
       [gameTypes addObject:gameTypeObject];
   }
   self.gameTypes = gameTypes;
}

- (void) changeArray //From the "method" binding of an NSButton in the 
nib file
{
   self.selectedType=@"Deathy"; //This adds a fourth item to the popup's 
list, rather than renaming the selected item.
}
@end

//  GameType.h**********************
//  TestPopup

#import <Cocoa/Cocoa.h>
@interface GameType : NSObject
{
   NSString *type;
}
@property (readwrite, retain) NSString *type;
@end

//  GameType.m *********************
//  TestPopup
#import "GameType.h"
@implementation GameType
@synthesize type;
@end