Re: Conceptual MVC Help

FROM : Michael Babin
DATE : Tue May 20 20:30:33 2008

On May 20, 2008, at 9:41 AM, Johnny Lundy wrote:

> QUESTION: How would you implement the binding to the model objects 
> "popUpArray" and "selectedGame" so that the popup loads from 
> "popUpArray" and its selection is kept in sync with the property 
> "selectedGame?" Specifically, is there a way to do it without 
> instantiating the object PopUp in the nib file?
>
> I know how I have done it, and page 118 of Aaron's 3rd edition says 
> the same, but I want to hear if there is a "pure" MVC-compliant way 
> to do it.


If you want to bind your array controller to properties of Popup and 
don't want to instantiate Popup in the nib, then create a path through 
File Owner (or in the case of MainMenu.nib, the application delegate 
object) to get the Popup object.

For example:

AppDelegate.h
@interface AppDelegate : NSObject {
   Popup    *popup;
}

@property (readonly) Popup *popup;

@end

AppDelegate.m
@implementation AppDelegate
@synthesize popup;

- (id) init
{
   self = [super init];
   if (self != nil) {
       popup = [[Popup alloc] init];
   }
   return self;
}

@end

Change your Popup object to set-up your data in its init method, 
rather than awakeFromNib (since it's no longer in a nib).

Then in your array controller, bind Content Array to the application 
delegate with a model key path of "popup.popupArray". The same applies 
to the array controller's selection (same as you would for Popup in 
the nib, just bind to the application delegate with a model key path 
starting with "popup".

The general point is to use a path through a controller to your model 
object outside of the nib.