How can I map keyboard keys to other keyboard keys in an app specific manner?

Question

I would like to have some way to specify that when I am focused on Spotify.app and I press the j key that it will translate into a ↓ key and be sent to the app. I would like this because I like vim style navigation but Spotify does not support remapping keyboard shortcuts.

Answer 1

@iGameRam's suggestion of KeyRemap4MacBook ended up working for me. I selected KeyRemap4MacBook because I am already using it to remap keys for me system wide. To do this I had to read the reference manual.

From the reference manual I found that there is a private.xml file that enables me to add more remapping values to KeyRemap4MacBook. By going to the KeyRemap4MacBook pref pane, going to the "Misc & Uninstall" tab and selecting "Open private.xml" I was able to open the file.

I had to add two elements to my private.xml. The first was:

<appdef>
  <appname>SPOTIFY</appname>
  <equal>com.spotify.client</equal>
</appdef>

This is because KeyRemap4MacBook does not ship with an app definition for Spotify. It does ship with many others. I need the app definition so my keyboard keybindings only apply for Spotify and are not system wide.

The second element I added was:

<item>
  <name>Spotify Vim Style Nav</name>
  <appendix>J and K works in Spotify</appendix>
  <identifier>private.spotify.vim_style_nav</identifier>
  <only>SPOTIFY</only>
  <autogen>--KeyToKey-- KeyCode::J, KeyCode::CURSOR_DOWN</autogen>
  <autogen>--KeyToKey-- KeyCode::K, KeyCode::CURSOR_UP</autogen>
</item>

This is the actual definition of the key bindings. The <identifier> tag is supposed to be unique for every key mapping. The manual suggests prefixing the identifier with private.. The <only> tag has to match an appname defined in the private.xml or shipped with KeyRemap4MacBook.

The <autogen> tags are supposed to contain the mappings. The manual has many examples on what kind of mappings that can be created. The two I have map the J and K keys to the Down and Up keys respectively.

Once the file has been saved, I just needed to press the "ReloadXML" button and then my mapping appeared as an option in the menu.

After selecting it everything worked as I wanted.

Answer 2

There are a couple of third party apps that can do what you are asking for (as i understood it ) , KeyRemap , Double Command . Please try this and let us know if this is what you were looking for.

Answer 3

If the action you want to perform can also be accessed through the menubar you could add a keyboard shortcut in system preferences/keyboard/keyboard shortcuts/Application short cuts.

Answer 4

Try Keyboard Maestro. It does a lot more than just remap keys, but it can be very useful for that purpose. You can set up all sorts of macros and actions on a global or per-app basis.

Answer 5

I know it works for controllers to keyboard, not sure about keyboard to keyboard, but you can try ControllerMate.

ControllerMate is a system that generates keyboard, mouse, and MIDI activity in response to triggers from gamepads, keypads, MIDI controllers, and other general-purpose input devices. It allows many types of devices to be used with software that would normally be compatible only with a keyboard, mouse, or MIDI source.

ControllerMate's internal devices generate activity based on a system of building blocks. Some building blocks respond to controls on input devices, other blocks trigger activity on ControllerMate's internal mouse and keyboard. Building blocks that implement timers, apply simple or complex logic, or perform basic math can also be created. Each individual building block performs a basic task, combinations of blocks can perform complex and creative functions.

A good thing about that app is you can choose to activate the remap for only the apps you want.