Re: strange "lockFocus sent to a view whose window is deferred" error with an NSOutlineView on Tiger: SOLVED

FROM : Martin Redington
DATE : Mon Mar 17 20:43:15 2008

I overrode -[NSTableView setFrameSize:] in my outline view class, so 
that it only calls super if the size has really changed.

This seems to fix the issue - setFrameSize: gets called a few times 
as I add the view - the first few times the values haven't changed. 
By the time they do change, the view's window seems to have been set.


On 17 Mar 2008, at 19:12, Martin Redington wrote:

>
> I overrode lockFocus, and stuck a breakpoint on it.
>
> #0    0x004f87ea in -[MyOutlineView lockFocus] at MyOutlineView.m:75
> #1    0x93310315 in -[NSView 
> _recursiveDisplayAllDirtyWithLockFocus:visRect:]
> #2    0x9332238f in _recursiveDisplayInRect2
> #3    0x9083eac0 in CFArrayApplyFunction
> #4    0x93310633 in -[NSView 
> _recursiveDisplayAllDirtyWithLockFocus:visRect:]
> #5    0x9330f493 in -[NSView 
> _recursiveDisplayRectIfNeededIgnoringOpacity:isVisibleRect:rectIsVisib
> leRectForView:topView:]
> #6    0x9330e382 in -[NSView 
> _displayRectIgnoringOpacity:isVisibleRect:rectIsVisibleRectForView:]
> #7    0x9330dcae in -[NSView displayIfNeeded]
> #8    0x933043ab in -[NSClipView _immediateScrollToPoint:]
> #9    0x9343bd92 in -[NSScrollView scrollClipView:toPoint:]
> #10    0x932cf34f in -[NSClipView _scrollTo:animate:]
> #11    0x932cee3b in -[NSClipView _scrollTo:]
> #12    0x932cecc3 in -[NSClipView _reflectDocumentViewFrameChange]
> #13    0x932acc75 in -[NSView _postFrameChangeNotification]
> #14    0x932cdd75 in -[NSControl setFrameSize:]
> #15    0x933a256d in -[NSTableView setFrameSize:]
> #16    0x933a0c82 in -[NSTableView tile]
> #17    0x933a09d5 in -[NSTableView _tileAndRedisplayAll]
> #18    0x932aa113 in -[NSView _setSuperview:]
> #19    0x933a3f86 in -[NSTableView _setSuperview:]
> #20    0x932a9d51 in -[NSView addSubview:]
> #21    0x932c72cf in -[NSClipView setDocumentView:]
> #22    0x932c70d0 in -[NSScrollView setDocumentView:]
> #23    0x00091f2b in -[MyController(Private) setOutlineView:] at 
> MyController.m:3967
>
> When lockFocus is called, the MyOutlineView has its superview set, 
> but not its window.
>
> Its possible that window is set lazily, and this is normal, but it 
> seems to be non-nil every time it gets past that point without 
> erroring.
>
> The other odd thing is that I don't see lockFocus get called at all 
> on -[NSScrollView setDocumentView:] when there's no error, or when 
> my other outline view gets set.
>
> Presumably, something in the state of that outline view is kicking 
> off the redraw before the view is ready.
>
>
> On 17 Mar 2008, at 17:45, Martin Redington wrote:
>

>>
>> On 17 Mar 2008, at 17:07, Michael Nickerson wrote:
>>

>>>
>>> On Mar 17, 2008, at 9:06 AM, Martin Redington wrote:
>>>

>>>>
>>>> I'm seeing the following error
>>>>
>>>> 2008-03-17 12:42:11.916 MyApp[11155] *** Assertion failure in -
>>>> [MyOutlineView lockFocus], AppKit.subproj/NSView.m:3248
>>>> 2008-03-17 12:42:11.917 MyApp[11155] lockFocus sent to a view 
>>>> whose window is deferred and does not yet have a corresponding 
>>>> platform window
>>>>

>>>
>>> You usually run into this error when a view tries to draw to a 
>>> window that hasn't been displayed at all yet.  I don't know if 
>>> this is the case for you, since you're talking about swapping 
>>> views, though - are you actually swapping out windows when you do 
>>> this?
>>>
>>> Anyway, you can try to make the window non-deferred (you can 
>>> deselect the checkbox for that in IB) and see if you get the 
>>> error then.  Doing that makes the window make a connection to the 
>>> window server when it's created rather than when it's first 
>>> displayed.

>>
>> The window is a single window app. Making the window non-deferred 
>> makes no difference.
>>

>>>
>>> If that doesn't help, is the scroll view you're adding the 
>>> outline view to part of the view hierarchy when you do that? 
>>> Maybe there was a bug in Tiger where the scroll view tried to 
>>> display the document view immediately when it's set and if it's 
>>> not actually part of a window I suppose this might pop up. 
>>> That's all just a guess, though.

>>
>> Yep. The scrollview is the place holder for the views, so that's 
>> always in place.
>>
>> I'll try and get a test case together - with a bit of luck I'll 
>> find a workaround while I'm doing that.
>>
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