Re: persistence and NSOutlineView
Re: persistence and NSOutlineView
- Subject: Re: persistence and NSOutlineView
- From: Alex Rice <email@hidden>
- Date: Fri, 31 May 2002 18:20:50 -0600
On Friday, March 22, 2002, at 11:22 PM, Anders Pytte wrote:
I don't "get" what the persistence features of NSOutlineView (and its
data delegate) are for.
Can someone give me the basic idea?
Anders, Hi I have asked the same question recently on cocoa-dev and
macosx-dev lists and got no responses, except someone else asking if I
figured it out ;-)
Alas, I still don't understand *how* NSOutlineView does this, but I have
got it working, and it's cool. The basic idea behind the persistence
methods in NSOutlineView is so that if you have [olview
setAutosaveExpandedItems:YES]; then the NSOutlineView can use object
persistence to take "snapshots" of the expansion state of each item.
Then when your app or document is loaded at some time in the future, the
outlineview can set the expansions of the outlineview items for the user.
The implementation is very simple if your node items implement NSCoding.
I've put together a sample project illustrating this. If you have
studied Apple's appkit example DragNDropOutlineView, this might be a
good one to look at as well because I have simplified the node class for
an outlineview datasource compared to the DragNDropOutlineView project.
http://www.mindlube.com/files/cocoa/NSOutlineViewPersistence.tar.gz
Alex Rice <email@hidden>
Mindlube Software
http://www.mindlube.com/
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