Bug 397397

Summary: No access to the client that changed desktop in KWin::Client.desktopChanged() signal
Product: [Plasma] kwin Reporter: LinG <lingtjien>
Component: scriptingAssignee: KWin default assignee <kwin-bugs-null>
Status: RESOLVED NOT A BUG    
Severity: normal    
Priority: NOR    
Version First Reported In: 5.13.3   
Target Milestone: ---   
Platform: Arch Linux   
OS: Linux   
Latest Commit: Version Fixed/Implemented In:
Sentry Crash Report:

Description LinG 2018-08-12 11:26:28 UTC 
I'm trying to let my script hook into the default KWin methods to change client desktops but I can't seem to get access to the client that is changing its desktop.

The API describes for the KWin::Client object the desktopChanged() signal without arguments whereas I would expect it to be similar to any of the other signals such as clientStartUserMovedResized(KWin::Client *) which gives the user access to the client that changed by its argument.

I tried to get access to the client that switches desktop using the active client (workspace.activeClient) but this return null in this method.

I'm not sure if this is intended behavior or if it's a bug, but either way I would like to get access to the client which had its desktop property changed. How do I do this?
Comment 1 Martin Flöser 2018-08-12 17:16:48 UTC 
You connect to the client's signal desktopChanged. This means you already have the client. Otherwise you could not even connect to the signal. It's your task to capture it appropriately in the lambda.
Comment 2 LinG 2018-08-12 18:48:01 UTC 
Yes, I understand that at the moment when I'm connecting to the signal I have access to the client, but I don't understand how I get access to the client inside the callback method that I provide for when the signal gets triggered.

My current understanding is:

```
client.desktopChanged.connect(function () {
  // how do I get the client inside this callback?
})
```
Here I provide a method (callback/lambda) that gets triggered whenever the desktop of this client changes.

The gap in my knowledge is then, how I would get access to the client inside this callback?

You refer to capturing the client in this lambda, could you please give a small example of how I would go about doing this?