Re: NSTreeController / CoreData still broken in 10.5?
Re: NSTreeController / CoreData still broken in 10.5?
- Subject: Re: NSTreeController / CoreData still broken in 10.5?
- From: "Adam Gerson" <email@hidden>
- Date: Mon, 24 Mar 2008 01:20:37 -0400
Thanks Chris,
I am going to look into creating a category. Its not something I have
ever done, but now I have some bedtime reading for tonight.
http://developer.apple.com/documentation/Cocoa/Conceptual/ObjectiveC/Articles/chapter_4_section_1.html
Would you suggest a category that extends an NSManagedObject?
Adam
On Sun, Mar 23, 2008 at 10:08 PM, Chris Hanson <email@hidden> wrote:
> On Mar 23, 2008, at 4:55 PM, Adam Gerson wrote:
> > A specific question:
>
> It is always good to ask specific questions. "Is ____ still broken in
> 10.5?" is not a very specific question, especially since there may be
> a number of developers who are using it quite successfully in Mac OS X
> 10.4.
>
>
> > If I want to model parent and child entities that have a
> > completely different set of attributes (one is a group of objects, the
> > other is the objects themselves) am I better of not using
> > NSTreeController and CoreData?
>
> NSTreeController and Core Data are entirely orthogonal here --
> specifically, Core Data has nothing at all to do with your question.
> Your question would be the same regardless of whether Core Data is
> involved.
>
>
> > One problem I have already run into is
> > that when you bind your entire OutlineView column to a
> > NSTreeController entity it wants the parents and children to all have
> > the same attributes.
>
>
> NSTreeController expects every column of an NSOutlineView it is
> controlling to have the same attributes, and it expects every object
> at every level of the hierarchy it displays to use the same keys for
> both the children of a node and for whether a node is a leaf. That's
> just how NSTreeController is designed.
>
> One way you can interoperate with this in your own code is to *not*
> bind directly to modeled attributes and relationships, but instead
> bind to keys that you define in categories in your own code. For
> example, let's say you're showing a filesystem hierarchy. You have
> two classes of item, File and Folder, where File instances are leaf
> nodes and Folder instances can have contents. You could add -
> isLeafForTreeController and -childrenForTreeController methods to each
> class, to return the appropriate values.
>
> You may also be able to work with NSTreeNode objects directly -- which
> are used to represent the contents of an NSTreeController in 10.5 --
> but unfortunately how to do so is still very sparsely documented.
> (It's not clear to me whether you can just set the content of a tree
> controller to a collection of NSTreeNode instances, for example.)
>
> -- Chris
>
>
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