Description

Adding support for checking is a dark mode for the Linux desktop environment without any breaking changes affecting anything else or doing further code refactoring

The changes are:

• Update the README.md to mention which Linux desktop environments are supported and what are the limitations
• Fix the desktop environment check-in isGnome in order to fix a bug that will happen when you have installed both KDE plasma desktop and Gnome on the same distro, the previous check will return true if the Gnome Desktop environment was installed regardless of the current used desktop environment is KDE or Gnome
• Use System.getenv instead of running a process to get output from the terminal for checking isGnome and isKde
• Add isKde method check in the isSupported static method and in createDetector
• Add KdeThemeDetector, since there is no way to check if the system is dark or light and we only can get the installed look and feel packages and the current used one, using this command :
  grep "^LookAndFeelPackage=" ~/.config/kdeglobals | awk -F "=" '{print $2}'
  would work and print the currently used look and feel package name, instead I used FileReader and read the file and got the LookAndFeelPackage property, the check will check if it's one of the defined dark look and feel packages, if not then it will check if it contains dark in a non-case sensitive way

The listeners are not supported yet as it would require more time and testing, I was hoping for an example module to simplify the development for all the developers to try and test, we might need to write a few tests too

I used a virtual machine and copied the source code into an example project to test the change since I couldn't switch to my Linux machine

KDE Plasma desktop doesn't have any straight way to check if the theme is dark or not in the terminal so searching online for A Linux command on KDE Plasma Desktop to check if the theme is dark or light will probably mention that you need a third party package installed on the system.

Related issues:

• Doesn't close add KDE support #31 yet since the listeners are not supported yet

Testing

I tested the changes on Ubuntu which has the default gnome desktop environment and KDE plasma desktop installed, I switched to both and tested the changes to ensure to not create any new bugs with this feature but still more testing is welcome

I would like to thank you for your efforts for this library, I also noticed some areas for potential improvement that are outside of the purpose of this feature.
Feel free to ask for any additional changes.