Re: NSTreeController and insertObject:atArrangedObjectIndexPath:
Re: NSTreeController and insertObject:atArrangedObjectIndexPath:
- Subject: Re: NSTreeController and insertObject:atArrangedObjectIndexPath:
- From: Michael Babin <email@hidden>
- Date: Sat, 19 Jun 2010 06:40:46 -0500
On Jun 18, 2010, at 5:53 PM, Tony Romano wrote:
> Scenario: Adding a new node to a NSOutlineView backed by a NSTreeController.
>
> 1. Create a new internal object add add it to the data store(file system). This will be my representedObject in the treecontroller
> 2. Compute the path and call insertObject:atArrangedObjectIndexPath:
>
> the treecontroller does 2 things during the call to insertObject:
>
> 1. It calls my getter, children, and asks me for all the children under the parent node I have added the new node to. I give it the list INCLUDING the newly created node since it is now in the store.
> 2. Then it calls the setter, setChildren, and gives me the newChildren list. Which now has an additional copy of the new node, one from the getter call and one from the insertAt call. I know this for a fact because I purposely added some data to the newly created node for the insert to distinguish them.
>
> From the UI, the outlineview is correct, but my internal child list has the extra node. It's not displayed because the treecontroller optimizes when to ask me for a childlist. I have a work around which I don't like to basically lock out the getter method and just return the current child list(i.e the previous child list which doesn't have the new node added from the file system). Anyone experience this before and have a recommendation?
I will qualify this by saying that I don't have much direct experience with using NSTreeController.
In this case, it appears that the problem is that you are effectively adding the new object twice. Your step 1 adds it directly to your model. If this was done in a KVO compliant way, then the NSTreeController should take note of the change and update the NSOutlineView for you (making step 2 unnecessary). Alternatively, you could add the new object to your model through the NSTreeController (your step 2) and omit step 1.
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