On Sep 7, 2014, at 7:02 AM, Ken Thomases <k...@codeweavers.com> wrote:
> On Sep 7, 2014, at 5:15 AM, Daryle Walker <dary...@mac.com> wrote:
>
>> Right now, the menu item that holds the submenu where the overflow menu
>> items go is always visible. I was thinking of controlling its visibility
>> with Cocoa Bindings. I select the menu item in the Interface Builder part of
>> Xcode, go to the Bindings Inspector, reveal the Hidden attribute settings,
>> and set the binding to my app’s delegate. Under the Model Key Path, I put
>> “self.my2ndCoordinator.overflowArray”. Now, that’s an array and I need a
>> Boolean. I tried “.count” and “.@count” at the end, and neither worked.
>
> What does "neither worked" mean? What happened?
Putting “my2ndCoordinator.overflowArray” gives me a red exclamation stop-sign
in the text field with the tool-tip text: “The Hidden expects to be bound to an
object of type NSNumber, but my2ndCoordinator.overflowArray is of type
NSArray.” Appending a “.@count” gives a grey exclamation stop-sign with a
tool-tip of: “Xcode cannot resolve the entered keypath”. Now when I use
“.count” I get no complaints, although I did before writing the first message.
(Did leaving out the “self.” make a difference?) I do end up crashing ("An
uncaught exception was raised” followed by “[<__NSArrayM 0x60000004a770>
addObserver:forKeyPath:options:context:] is not supported. Key path: count”).
> ".@count" should work. ".count" would not. That effectively attempts to
> construct an array by asking each _element_ of overflowArray for its "count"
> property, which is always the way that KVC on arrays works. This will
> probably fail because the elements don't have a count property and even it
> succeeds, it would result in an array which is not an appropriate result for
> the hidden binding.
>
> (Also, starting a key path with "self." is just redundant.)
>
>> Even then, I still need to stick in the “> 0” part somewhere (unless
>> Bindings does the zero vs. non-zero to Boolean conversion C does).
>
> I don't know that I'd describe it as bindings "doing" that "conversion", but,
> yes, in a boolean context, 0 means false and non-zero means true. Since you
> presumably want the menu to be hidden when the count is 0, you want to use
> the NSNegateBoolean value transformer set on the binding.
—
Daryle Walker
Mac, Internet, and Video Game Junkie
darylew AT mac DOT com
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