Re: NSOutlineView with Multiple Core Data Entities

[Jonathan Dann]

Ah yeah, that bug is intentional! The model uses an abstract TreeNode entity, which the tree controller is set to; however when you want concrete LeafNode and GroupNode entities (or sub-entities thereof) you need to create your own -add: methods so you can insert the correct entity into the tree. As the tree controller has its entity set to TreeNode (abstract, so it can work will all sub-entity types), when calling -add: and addChild: it simply tries to insert an abstract entity. Only the GroupNode responds to -isSpecialGroup, hence the exception.

Sorry for the confusion. Hope this clears it up.

Jonathan

www.espresso-served-here.com

On 25 Jul 2008, at 21:30, Garrett Bjerkhoel wrote:

I put those buttons, linked to -add: and -addChild:, in the project to emphasise that these no longer work when you want a non-trivial tree structure with multiple entities in the same tree. What I do for the case you want is have an -insertGroupNode: method which creates the correct entity and inserts it into the tree at the index path you want. For the default groups I do that in code, setting their -displayNames and setting -isSpecialGroup to YES so that the NSOutlineView delegate method -outlineView:isGroupItem: can interrogate the all the GroupNodes and will draw it in the correct way (like MAILBOXES, etc) when -isSpecialGroup returns YES. In a shipping app I'd bracket such calls (when you don't know what type of node your dealing with) with a -respondsToSelector: or - isKindOfClass: call.

Here is a rough sketch of my datamodel. If you like I can take a screenshot and post a link to it.

Client
---Project
----Todo
Writeoff
---Item



On regards to your project, here you go:
Once it loads, nothing is clickable :(

In the debugger, this is what it says:


On Jul 25, 2008, at 12:33 PM, Jonathan Dann wrote:

By each entity having its own group, I am refering to say Mail.app how it has "MAILBOXES", then "REMINDERS", or in iTunes "DEVICES", and "LIBRARY". My intention was to have multiple group nodes as well as multiple child nodes. 2008-07-25 12:35:01.031 SortedTree[1526:10b] *** -[ESTreeNode isSpecialGroup]: unrecognized selector sent to instance 0x133d20

On 25 Jul 2008, at 17:21, Garrett Bjerkhoel wrote:

I have a NSOutlineView hooked up to a NSTreeController, which has multiple entities inside of it. I would like to know how to set it up having each entity having its own "group". I have downloaded Jonathan Dann's example, which compiles but freezes. I can see how his Core Data model works, but I already have mine set.

Haha! That's great, sorry about that. I'm interested to know where it freezes, can you tell me more so I can fix it, please!

Can you explain what you model looks like in a little more detail, and what you mean by each entity having its own group. Do you want a single group node entity or multiple group nodes as well as multiple child node entities?

Do I need to have both of my entities have a parent entity in which my NSTreeController reads from that one parent entity?

Jonathan

www.espresso-served-here.com

If I understand you correctly, the general concept it to have a single abstract "TreeNode" entity. This is the entity that the tree controller concerns itself with, you then can make as many concrete entities as you like that inherit from your abstract one.

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