martes, 15 de abril de 2014

My first ubuntu indicator

I was reading about Unity indicators and how to create one here and here and decided that I will give it a try, but and indicator of what? it must be something useful but not too complicated to implement because I want to keep things simple so I ended up create a touch pad indicator that will allow me to turn on and off the mouse pad of my laptop.

If you need to disable your touch pad of any reason take a look at this post


Make sure that you have the package python-appindicator installed, you can install it using this command:
sudo aptitude install python-appindicator

We will also use pygtk and pynotify libraries.

The source code

My source is divided in two main sections the indicator menu items and the event handlers all defined inside one single class called TouchPadIndicator. You can find this indicator source code here:
The touch pad indicator constructor (__init__) is responsible for creating an appindicator.Indicator instance and setup the menu. This constructor also setup the indicator icon, I was not able to find a list of all possible icons but in some forums I found references to the Gtk Stock and to the folder /usr/share/icons/CURRENT_THEME where CURRENT_THEME is the name of theme actually in use, listing files on some folders under /usr/share/icons allows me to find this file name gpm-mouse-060.svg so figured that using "gpm-mouse-060" should work and it did at least in my computer, so if you can't see the indicator logo you can check that.
Setup the indicator menu is quite simple, you need to:
  • Create a gtk.MenuItem instance
  • Bind your instance to the correct event handler
  • Show the menu (make it visible), and
  • Add the menu item to the main menu
My indicator have two options, namely: "Quit" and  "Toogle touch pad".
Quit just call to sys.exit to terminate the execution
Toogle touch pad is the interesting part it uses a class called TouchPadDevice to detect the current touch pad status and also calls the notify function to show a nice information message.
The part that deals with the device status is inspired by this ask ubuntu answer