Custom field editors

FROM : John Stiles
DATE : Fri Jan 04 20:35:38 2008

I'm looking at creating a custom field editor (so I can filter out
keystrokes in various types of controls in a consistent way).
The text editing programming guide has a section called "How to
Substitute a Custom Field Editor", with an example snippet which seems
nice and simple:

> (id)windowWillReturnFieldEditor:(NSWindow *)sender toObject:(id)anObject
> {
>    if ([anObject isKindOfClass:[NSTextField class]])
>    {
>        return [[[myCustomFieldEditor alloc] init] autorelease];
>    }
>    return nil;
> }



(Admittedly, there are two problems in the code—no leading hyphen and a
lowercase class name—but I'm going to let that slide for now :) )
However, according to the docs for
-windowWillReturnFieldEditor:toObject:, this code is actually broken:

> Discussion
> This method may be called multiple times while a control is first
> responder. Therefore, you must return the same field editor object for
> the control while the control is being edited.


This seems to directly contradict the sample code above, so which is
correct? I'll happily file it, but I just wanted to run this past
someone who might have already been down this road before.