Accepting drops of volumes on Dock icon

I'm writing a Cocoa application that nee开发者_开发问答ds to accept drops of mounted volumes on its Dock icon. It is not document-based; I intend to dispatch each volume to the appropriate handler in application:openFiles.

I have gotten the Dock to light up my application's tile for the drag, but upon dropping, my application shows an alert: “The document [volume name] could not be opened. [My application] cannot open files of this type.” My application:openFiles: method never runs, even though the delegate is hooked up and is sent other delegate messages.

So, what's the correct way to accept a drop of a volume onto my Dock tile?

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Probably your Info.plist is not properly set up. It should include something like this:

CFBundleDocumentTypes =     (
    {
        LSItemContentTypes =             (
            "public.volume"
        );
    }
);

or you can use CFBundleOSTypes and disk instead if you need to support pre-10.5.

I was able to get application:openFiles: to work by doing this.

If you're already doing that, it's probably Launch Services getting confused... clean and rebuild your project, try a different user account, use lsregister, wave dead chickens, etc.

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… the delegate is hooked up and is sent other delegate messages.

Or so I thought.

Mea culpa—I had, in fact, not even created the delegate. I'm not sure why I thought I had.

With the delegate instantiated and hooked up in the MainMenu nib, plus the Info.plist change Nicholas Riley suggested, the drops now work.