Register Double-Click on Desktop (but not on Icons !)

Question

Here's a though question: I need to find out when the user double-clicked the OS X desktop, but not icons on it.

Now, I have thought of the following solutions, though I am not sure if they are doable:

1. Using desktop icons position (not sure how to get them), and the size of the desktop icons, we could theoretically check once the user double-clicks on the desktop, if it is inside one of the icon areas. Contra: Might not be flawless as some icons might be transparent or not taking up the entire icon size.

2. Maybe there is a variable that tells us if a icon from the desktop has been clicked? Then we could just check if that variable has been activated when the user double-clicked the last time the desk.

I am certainly still open to other (better) solutions, but they need to be sandboxable for the Mac App Store.

Answer 1

This is probably not going to be appropriate for the Mac App Store, for a number of reasons.

First, how are you going to intercept clicks outside your window? There are a few different mechanisms for this (eg, event taps), but none of them are allowed in sandboxed apps. And that's intentional, and for a good reason—you're not supposed to be interfering with other apps or with the OS.

On top of that, it's hard to imagine that whatever you're trying to do wouldn't count as non-standard UI/HIG stuff, which is another reason for rejection.

But, assuming none of that were a problem, and you could intercept clicks on the desktop, there's no documented way to get all the icons on the desktop, so you have to read the .DS_store file directly, which means relying on private implementation information, which is another thing you're not allowed to do.

Finally, you have to get access to that .DS_store file. Unless you're expecting the user to drag the (invisible) file or its parent directory to your app or select it in an NSOpenPanel or something, the only way to get such access from inside the sandbox is via a temporary exception entitlement. Which you can't use unless you can justify to the reviewer why you need it as a workaround for a bug or limitation in the OS. So, what's your justification going to be?