Cfrgtkky

I'm trying to write a custom NSMenu which will be able to list for key input and intercept the necessary events. This is to provide a simple search-as-you-type functionality for my open source clipboard manager.

It seems like the only way to do this is to install a custom Carbon event handler which will listen for key events and handler them accordingly, but it seems like there is an issue with such a custom handler.

Normally, I can propagate events downwards to other handlers (e.g. system ones) and they should be gracefully handled. This can be done by a simple callback:

let eventHandlerCallback: EventHandlerUPP = { eventHandlerCallRef, eventRef, userData in

  let response = CallNextEventHandler(eventHandlerCallRef, eventRef!)

  print("Response (response)")

  return response

}

This callback works perfectly and prints Response 0 all the time. This response means that the event is handled correctly.

However, things get weird once we send mouse events before keyboard events. In such case, the callback fails and prints Response -9874. This response means that the event was not handled correctly.

It seems like the event fails to be handled somewhere below my custom view and I don't know where exactly or how to overcome this issue.

To reproduce, I've uploaded the code to Gist which can be added to XCode playground and run. Once you see menu popup, press some keys (preferably arrow keys as they won't close the menu) and observe Response 0 in the console. After that, move cursor inside the menu and press more arrow keys. You should see Response -9874 in the console now.