Re: Cant disable Item of NSPopUpButton

[Sebastian Reitenbach]

On Friday, September 20, 2024 18:57 CEST, "H. Nikolaus Schaller" 
<hns@goldelico.com> wrote:

> Hi,
> 
> > Am 20.09.2024 um 19:20 schrieb Sebastian Reitenbach 
> > <sebastia@l00-bugdead-prods.de>:
> > 
> > Hi,
> > 
> > I've a NSPopUpButton with some items. Some of them I want just to be 
> > disabled.
> > To do so, I thought I can just get away with:
> > 
> > [[self.popupButton itemWithTitle: @"Item 2"] setEnabled: NO];
> > 
> > but that is not the case.
> > 
> > Is that supposted to work that way, if at all? If so, any hint what I'm 
> > doing wrong?
> 
> I think (based on Cocoa experience) you must implement some validateMenuItem: 
> or similar method for the target of the popup button. So that it can return 
> YES or NO on demand.
> 
> To make it dynamical I think the validateMenuItem: is passed the item in 
> discussion and you can make decisions based on e.g. [item action] or [item 
> title] (not recommended) or [item representedValue]. This is a little similar 
> to the dataSource of an NSTableView. You never set values directly in the 
> NSTableView but it asks some other object to provide them but only on demand 
> by whatever algorithm fits.
> 
> This is called when a users opens the menus and depending on the result the 
> setEnabled: is called automatically (and overwrites your changes).

relying on validateMenuItem: didn't worked out, since I couldn't properly check 
isEnabled: even though, the entry was disabled.
As I understand now, how the validateMenuItem works is:
the NSMenuItem has to have a action defined. 
Then when the Menu gets popuplated with items, and it's shown in the UI, the 
NSPopupButton, or someone sends a respondsToSelector: to the configured action: 
target class, and if that responds YES, the validateMenuItem: method is called 
in the target.
This will mark all those itemas I want to be disabled as disabled, but I can't 
test, if the current selected item is disabled, and choose a different one in 
case it might be.

However, looking again, I stumbled upon: NSPoUpButtons setAutoenablesItems: 
Once I set this to NO, I can use setEnabled: and isEnabled manually, and 
achieve what I was looking for.

cheers,
Sebastian



> 
> BR,
> Nikolaus
>