Re: -outlineView:heightOfRowByItem: gets an item of NULL??

FROM : John Stiles
DATE : Thu Feb 21 21:06:46 2008

Fair enough, but the root item is never represented graphically in a
table, so there wouldn't be a need to ask for its row height…?
Anyway, I filed a radar… we'll see what happens.


Mike Abdullah wrote:
> Although the docs don't mention it for this method, quite often an
> item of nil is used to represent the tree's root object. I would
> suggest therefore returning the default height of a table cell.
>
> Mike.
>
> On 21 Feb 2008, at 19:32, John Stiles wrote:
>

>> My outline view can occasionally get multi-line entries, so I've
>> implemented -outlineView:heightOfRowByItem: in the delegate. Normally
>> this works like a charm.
>>
>> Now I'm working on some code to support dragging and dropping items
>> between one outline view and another outline view.  (For what it's
>> worth, none of the items in this particular outline view are using a
>> nonstandard height in this case.) Suddenly, I've found that if I
>> start dragging items back and forth, after about ten tries or so,
>> -outlineView:heightOfRowByItem: is called with an item of "nil"!! I
>> haven't narrowed down a distinct pattern yet.
>>
>> This causes an assertion to fire in my code because the first thing I
>> do is assert that [item isKindOfClass:[MyItem class]]. This assertion
>> hasn't ever gone off before.
>>
>> Is it expected that this delegate method could occasionally be called
>> with a nil item?
>>
>> As a workaround, should I just return [outlineView rowHeight] if I
>> get nil?
>>
>>
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