CODEWITHSUNDEEP
objective-cmacoscocoansmenunsmenuitem
A O
A O

Reputation: 5698

Can I conditionally disable an NSMenuItem that is only enabled when the first responder responds to a selector?

I have an NSMenuItem that is enabled/disabled based on whether or not the first responder responds to a specific selector.

My problem is that there are conditions in which I do not want the item enabled for the first responder.

But I can't just conditionally remove a method definition during runtime to disable the menu item

For an example of what I mean:
I have a NSDocument-based application, and I have two main subclasses-- an ImageDocument and a VideoDocument

I have an NSMenuItem called "Capture Frame", which turns a frame of a video into an image. But obviously this should be disabled on an ImageDocument, and only enabled on a VideoDocument.

The NSMenuItem is enabled if the first responder responds to -captureFrame

The VideoDocumentController has a method, -captureFrame, so it's enabled. The ImageDocumentController does not, so the menu item is never enabled.

But, there are specific VideoDocuments that I do not want to have that menu item enabled for. What could be the best way for me to disable this menu item in order to handle special cases?

Upvotes: 0

Views: 573

Answers (1)

JWWalker
JWWalker

Reputation: 22717

In your VideoDocument class, override the NSDocument method validateUserInterfaceItem:. Alternatively, you can override validateUserInterfaceItem: in a subclass of NSDocumentController. Be sure to call super to keep the built-in functionality of this method. See Apple's docs on UI validation for an example.

Upvotes: 2

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