Re: NSBrowser tooltips (Tiger and Leopard)

FROM : Corbin Dunn
DATE : Wed Nov 07 00:09:21 2007

>
>
> On Leopard, the method also doesn't get called, but I do get a 
> tooltip for my root item (the first column of the browser has only 
> one item), with text that seems to be taken from the text of my 
> (custom) NSBrowerCell. None of the other items (incorrectly) show 
> tooltips at all.
>


That's the expansion tool tip. It is documented, and mentioned in the 
release notes:

http://developer.apple.com/releasenotes/Cocoa/AppKit.html

> NSCell Automatic Expansion ToolTip FrameNSCell has some new API to 
> support expansion tool tips in certain controls:
> - (NSRect)expansionFrameWithFrame:(NSRect)cellFrame inView:(NSView 
> *)view;
> - (void)drawWithExpansionFrame:(NSRect)cellFrame inView:(NSView 
> *)view;
> An expansion tool tip allows one to see truncated text in a special 
> floating window that is similar but different from a normal ToolTip. 
> Currently, NSTableView, NSOutlineView and NSBrowser display 
> expansion tool tips when the text is truncated. If you have a cell 
> that will be displayed in one of these controls, it is recommended 
> that you implement the above methods to properly support the 
> expansion tool tip feature. By default, the methods are properly 
> implemented in NSTextFieldCell and NSBrowserCell. NSCell will always 
> return NSZeroRect, and prevent the expansion from happening. For an 
> example of how to implement it, see the SimpleBrowser demo app.
>
> Clients of NSTableView, NSOutlineView and NSBrowser can prevent the 
> cell expansion from happening on a particular row/column by using 
> the new delegate methods declared in the appropriate header files.
>
>




> However, after this tooltip has been displayed, the underlying 
> NSBrowserCell seems to have been released by something, judging by 
> the crashes I get next time it's accessed.


This is because you aren't properly implementing copyWithZone; in it, 
you should retain or copy your ivars.

corbin