Gnome Shell Extension Key Binding
Solution 1:
TL;DR
Here is a class:
KeyManager: new Lang.Class({
Name: 'MyKeyManager',
_init: function() {
this.grabbers = new Map()
global.display.connect(
'accelerator-activated',
Lang.bind(this, function(display, action, deviceId, timestamp){
log('Accelerator Activated: [display={}, action={}, deviceId={}, timestamp={}]',
display, action, deviceId, timestamp)
this._onAccelerator(action)
}))
},
listenFor: function(accelerator, callback){
log('Trying to listen for hot key [accelerator={}]', accelerator)
let action = global.display.grab_accelerator(accelerator)
if(action == Meta.KeyBindingAction.NONE) {
log('Unable to grab accelerator [binding={}]', accelerator)
} else {
log('Grabbed accelerator [action={}]', action)
let name = Meta.external_binding_name_for_action(action)
log('Received binding name for action [name={}, action={}]',
name, action)
log('Requesting WM to allow binding [name={}]', name)
Main.wm.allowKeybinding(name, Shell.ActionMode.ALL)
this.grabbers.set(action, {
name: name,
accelerator: accelerator,
callback: callback,
action: action
})
}
},
_onAccelerator: function(action) {
let grabber = this.grabbers.get(action)
if(grabber) {
this.grabbers.get(action).callback()
} else {
log('No listeners [action={}]', action)
}
}
})
And that's how you you use it:
let keyManager = new KeyManager()
keyManager.listenFor("<ctrl><shift>a", function(){
log("Hot keys are working!!!")
})
You're going to need imports:
const Lang = imports.lang
const Meta = imports.gi.Meta
const Shell = imports.gi.Shell
const Main = imports.ui.main
To stop listening:
for (let it of keyManager.grabbers) {
global.display.ungrab_accelerator(it[1].action)
Main.wm.allowKeybinding(it[1].name, Shell.ActionMode.NONE)
}
Explanation
I might be terribly wrong, but that what I've figured out in last couple days.
First of all it is Mutter who is responsible for listening for hotkeys. Mutter is a framework for creating Window Managers, it is not an window manager itself. Gnome Shell has a class written in JS and called "Window Manager" - this is the real Window Manager which uses Mutter internally to do all low-level stuff. Mutter has an object MetaDisplay. This is object you use to request listening for a hotkey. But! But Mutter will require Window Manager to approve usage of this hotkey. So what happens when hotkey is pressed? - MetaDisplay generates event 'filter-keybinding'. - Window Manager in Gnome Shell checks if this hotkey allowed to be processed. - Window Manager returns appropriate value to MetaDisplay - If it is allowed to process this hotkey, MetaDisplay generates event 'accelerator-actived' - Your extension must listen for that event and figure out by action id which hotkey is activated.