How to detect a Command C in my app (Swift)?

Question

I have a calculator app written in Swift, and it's fully compatible with custom keyboard shortcuts. I'm trying call a method when the user presses Command + C, however, whenever I try to assign the following custom shortcut, it just doesn't work:

UIKeyCommand(input: "c", modifierFlags: [.command], action: #selector(commandCAction))

The commandCAction method is never called, unlike the other shortcuts. I assume this is due to Apple reserving this shortcut. Are there any observers or methods that I can use to detect when the user presses Command + C on a physical keyboard?

score 2 · Answer 1 · answered Dec 20 '17 at 18:24

The documentation for UIKeyCommand says: "Key commands that map to known system events (such as cut, copy and paste) are automatically routed to the appropriate responder methods".

Your best approach may be to subclass the UI elements where you want to intercept the command and implement your own copy:.

score 1 · Accepted Answer · answered Dec 20 '17 at 21:32

I found the issue, for some reason this doesn't work on my simulator:

UIKeyCommand(input: "c", modifierFlags: [.command], action: #selector(commandCAction))

However, when I tried on a physical device, it worked! So that's a solution for someone with the same issue as me.

How to detect a Command C in my app (Swift)?

2 Answers2