Re: NSWindow's setContentView

FROM : Shawn Erickson
DATE : Mon Jun 19 17:35:33 2006

On Jun 19, 2006, at 4:02 AM, <cocoa> <cocoa> wrote:

> Shawn Erickson <<email_removed>> wrote :
>

>> On Jun 18, 2006, at 8:02 PM, Drarok Ithaqua wrote:
>>
>> &gt; For sake of simplicity, let's assume I want to swap the 
>> contents of
>> &gt; two windows, mainWindow and playlistWindow.

>
> From the Apple docs:
> The receiver retains the new content view and owns it thereafter. 
> aView is resized to fit precisely within the content area of the 
> NSWindow object. You can modify the content view’s coordinate 
> system through its bounds rectangle, but can’t alter its frame 
> rectangle (that is, its size or location) directly.
>
> This method causes the old content view to be released; if you plan 
> to reuse it, be sure to retain it before sending this message and 
> to release it as appropriate when adding it to another NSWindow 
> object or NSView.
>
> No mention of auto-releasing there, but something strange is 
> certainly going on.


Nothing strange is likely taking place and an autorelease is 
considered a release. So don't assume implementation from the 
documentation. Just stick to the simple Cocoa memory management rules 
and try not to debug things using retain counts.

> The other problem is that there seems to be weirdness with the 
> NSMovieView, as the contents of the playlistWindow appears in the 
> mainWindow just fine, but the MovieView disappears. When I swap 
> them back, it appears OK in the mainWindow again.
> Doesn't seem to like moving between windows.


Something is likely wrong in how you are swapping things around (or a 
bug in the framework but those happen very seldom). I move views 
between windows all the time (just need to make sure you are moving 
the correct view... some items you drop from IB into a nib are in 
fact contained in a parent view... say a scroller view).

> But that still doesn't resolve my retainCounts going screwy. Is 
> there a way to fine out what objects are retaining others?


Often best to audit your code and make sure you are balancing every 
retain with a retain/autorelease and not releasing/autorelease 
anything that you didn't alloc, copy, or retain yourself.

If you are crashing because of a memory issue search for and enable 
NSZombie support [1, 2]  also look at using ObjectAlloc [3] or 
OmniGroup's OmniObjectMeter [4].

-Shawn

[1] <http://developer.apple.com/technotes/tn2004/tn2124.html>
[2] <http://www.cocoadev.com/index.pl?DebuggingAutorelease>
[3] <http://developer.apple.com/documentation/Performance/Conceptual/
ManagingMemory/Articles/FindingPatterns.html#//apple_ref/doc/uid/
20001882-97995-TPXREF162>
[4] <http://www.omnigroup.com/developer/omniobjectmeter/> _______________________________________________
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