How to get back Launcher icon for emacs in 16.04?

Question

After installing 16.04 the Emacs icon in the Launcher turned into a question mark:

In 15.10, the icon looked more like this:

I guess the problem might be that I installed Emacs from source ( and not using sudo apt-get install emacs24 ). The binaray is now installed in /opt/emacs-24.5/bin/emacs.

I found this tutorial UnityLaunchersAndDesktopFiles for how to create .desktop files.

If I run find /opt/emacs-24.5/ -name '*.desktop' I get

/opt/emacs-24.5/share/emacs/24.5/etc/emacs.desktop
/opt/emacs-24.5/share/applications/emacs.desktop

and running find /opt/emacs-24.5/share/icons -name '*.png' gives

/opt/emacs-24.5/share/icons/hicolor/48x48/apps/emacs.png
/opt/emacs-24.5/share/icons/hicolor/32x32/apps/emacs.png
/opt/emacs-24.5/share/icons/hicolor/24x24/apps/emacs.png
/opt/emacs-24.5/share/icons/hicolor/128x128/apps/emacs.png
/opt/emacs-24.5/share/icons/hicolor/16x16/apps/emacs.png

How should I proceed now, to create a working .desktop file?

Update:

I have now tried the following:

• Copied the supplied desktop file that came with emacs to a local folder:

    cp /opt/emacs-24.5/share/applications/emacs.desktop ~/.local/share/applications/emacs.desktop
  

• Then changed the icon file name of that file:

  [Desktop Entry]
  Name=Emacs
  GenericName=Text Editor
  Comment=Edit text
  MimeType=text/english;text/plain;text/x-makefile;text/x-c++hdr;text/x-c++src;text/x-chdr;text/x-csrc;text/x-java;text/x-moc;text/x-pascal;text/x-tcl;text/x-tex;application/x-shellscript;text/x-c;text/x-c++;
  Exec=emacs %F
  Icon=/opt/emacs-24.5/share/icons/hicolor/48x48/apps/emacs.png
  Type=Application
  Terminal=false
  Categories=Development;TextEditor;
  StartupWMClass=Emacs
  Keywords=Text;Editor;
  

• Run desktop-file-validate:

   $ desktop-file-validate ~/.local/share/applications/emacs.desktop 
   /home/hakon/.local/share/applications/emacs.desktop: hint: value item "TextEditor" in key "Categories" in group "Desktop Entry" can be extended with another category among the following categories: Utility
  

• Run desktop-file-install:

   sudo desktop-file-install --dir=/usr/share/applications/ ~/.local/share/applications/emacs.desktop
  

Still the icon did not change. What am I missing?

Answer 1

There are two options:

1. The /opt directory is not in $PATH, which makes the .desktop file invalid, unless you added the directory manually. Usually applications in /opt have an absolute path in their Exec= line. Change it to the absolute path to the executable.

2. There might be another .desktop file in ~/.local/share/applications, taking the place of your custom .desktop file. Either:

   • drag your home-made .desktop file on to the launcher and see if it works (with correct icon).

   • If not, or alternatively, run the command:

     grep -rl emacs ~/.local/share/applications
     

   to find possible outdated or incorrect .desktop files, launching emacs

Answer 2

Seems like the problem was not using an absolute path name for the Exec key. Here is a modified /usr/share/applications/emacs.desktop file:

[Desktop Entry]
Name=Emacs
GenericName=Text Editor
Comment=Edit text
MimeType=text/english;text/plain;text/x-makefile;text/x-c++hdr;text/x-c++src;text/x-chdr;text/x-csrc;text/x-java;text/x-moc;text/x-pascal;text/x-tcl;text/x-tex;application/x-shellscript;text/x-c;text/x-c++;
Exec=/opt/emacs-24.5/bin/emacs %F
Icon=/opt/emacs-24.5/share/icons/hicolor/scalable/apps/emacs.svg
Type=Application
Terminal=false
Categories=Development;TextEditor;
StartupWMClass=Emacs
Keywords=Text;Editor;
X-Desktop-File-Install-Version=0.22

This seems to work fine now.