Re: NSTabView Fix

[Fred Kiefer]

Wolfgang Lux schrieb:
> Andreas Höschler wrote:
> 
>>
>>>>> and we need to make sure these two match in some way. And what I
>>>>> tried to do was just this. If I failed on doing so, please show me
>>>>> my > wrongs.
>>>>
>>>> Create a tabView and add four tabViewItems. _selected_item will be
>>>> 4. Then call selectedTabViewItem! Boohm!!!
>>>
>>> So what? Fred's change looked okay to me (and still looks so). The
>>> point is
>>> just that NSTabView fails to initialize the _selected_item instance
>>> variable
>>> properly. Adding the line
>>>   _selected_item = NSNotFound;
>>> in -initWithFrame: should fix this issue.
>>
>> If NSNotFound is and will stay defined as -1 then YES! Can we build on
>> that?
> 
> No, because 0x7fffffff != -1 :-) (see NSObject.h; it's the same on
> Cocoa). Anyway
> there is really no need to do so because the code (with two exceptions,
> see below)
> carefully checks whether _selected_item is NSNotFound before
> incrementing or
> decrementing the instance variable.
> 
> The two methods were the check is absent are -selectNextTabViewItem: and
> -selectPreviousTabViewItem:. These methods might be changed as follows
> 
>   - (void) selectNextTabViewItem: (id)sender
>   {
>   #if 0
>     /* the check below does work because 0x80000000 is cast to unsigned
> and thus
>      * greater than the number of items; nevertheless, checking
> explicitly for
>      * NSNotFound improves code clarity */
>     if ((unsigned)(_selected_item + 1) < [_items count])
>   #endif
>     if (_selected_item != NSNotFound && (unsigned)(_selected_item + 1) <
> [_items count]))
>       [self selectTabViewItemAtIndex: _selected_item+1];
>   }
> 
>   - (void) selectPreviousTabViewItem: (id)sender
>   {
>   #if 0
>     /* the check below works just because even NSNotFound-1 is greater
> than the
>        index of any item in the tab view and therefore
> selectTabViewItemAtIndex:
>        will set the selected item (redundantly) to nil (and thereby also
>        _selected_item to NSNotFound); nevertheless, checking explicitly for
>        NSNotFound improves code clarity. */
>     if (_selected_item > 0)
>   #endif
>     if (_selected_item != NSNotFound && _selected_item > 0)
>       [self selectTabViewItemAtIndex: _selected_item-1];
>   }
> 
> 
>> Sorry (to Fred), I haven't looked for a fix for the fix yesterday. I
>> just discovered that the modification broke my code and therefore
>> rolled back to the older implementation. I suppose _selected_item =
>> -1; in the init method will do the trick.
> 
> No, it won't. You have to use _selected_item = NSNotFound or you are
> going to
> break other things in NSTabView.m.
> 

Thank you for this patch. It is now in SVN.

Cheers,
Fred