Re: iTunes-like outline view using core data?
Re: iTunes-like outline view using core data?
- Subject: Re: iTunes-like outline view using core data?
- From: Ken Kania <email@hidden>
- Date: Sun, 05 Aug 2007 16:52:05 -0700
I assume you are using a NSTreeController to supply your NSOutlineView
with data. The reason for your duplicate listing of "header" and
"child" cells is you misunderstand the behavior of NSTreeController. As
you have it now, NSTreeController fetches all entities of type
"abstractOutlineEntity" (which means both concrete types in your case)
to display as roots in your tree. Thus your "My Cool Playlist" will
already be shown as a root node. Then, NSTreeController uses the child
key that you provide then to populate the subtree under each of these
nodes, which results in displaying "My Cool Playlist" again.
To fix this, you could specify a specific set or array of
"abstractOutlineEntity" to use as your content. Look under the bindings
panel in IB for your TreeController.
I'm trying to setup an iTunes-like outlineview with a core data
application. The goal is to have heading cells (like the "Library",
"Store", and "Playlist") that draw differently from their contents in
the tree. So far what I've tried to do is have an abstract core data
entity (we'll call it "abstractOutlineEntity"). Then I have two
concrete entities that have "abstractOutlineEntity" as their parent
object. In my nib file, I have the outlineview set to hold
"abstractOutlineEntity" entities. As for the two concrete entities,
one of them is supposed to act as a heading cell in the outlineview,
and the other is supposed to act as a child cell. This seemed like
the logical way to do this - b/c the outlineview is set to hold
"abstractOutlineEntity" entities which my concrete entities are.
Now when my app launches I can correctly display the heading cells,
but when I try to create a child object using a custom subclass, the
child object appears correctly as a child in the outlineview like it
should, but it also appears a second time as a root level object.
I've tried to draw the resulting tree below after trying to add a new
child object. Does anybody have any idea how to prevent this? Thanks
in advance.
-Library (heading cell)
-Playlists (heading cell)
- My Cool Playlist (child cell)
-My Cool Playlist (appearing again as a heading cell - not what i want)
Regards,
Carter
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