How to set XDG_DATA_DIRS ?

[abcfy2]

Qt search theme path from XDG_DATA_DIRS, see: https://doc.qt.io/qt-5/qicon.html#themeSearchPaths

But how could I set XDG_DATA_DIRS in AppImage?

[abcfy2]

I think maybe it's useful to add XDG_DATA_DIRS to squashfs-root/apprun-hooks/linuxdeploy-plugin-qt-hook.sh:

# generated by linuxdeploy-plugin-qt

# try to make Qt apps more "native looking", if possible
# see also https://github.com/AppImage/AppImageKit/issues/977#issue-462374883
# and https://github.com/AppImage/AppImageKit/issues/977#issue-462374883
case "${XDG_CURRENT_DESKTOP}" in
    *GNOME*|*gnome*|*XFCE*)
        export QT_QPA_PLATFORMTHEME=gtk2
        ;;
esac

export XDG_DATA_DIRS="${squashfs_root_path}/usr/share:${XDG_DATA_DIRS}:/usr/share:/usr/local/share"

[TheAssassin]

This likely has some side effects, I'm not sure if this is a good idea. Why would you need this variable to be set?

Using a second hook seems like an elegant solution.

[abcfy2]

I try to make a qt AppImage.

# From guide: https://docs.appimage.org/packaging-guide/native-binaries.html#qmake
./configure --prefix=/usr
make install INSTALL_ROOT=AppDir

And AppImage prefix is not /usr/, so qt application cannot find the theme icons, so I have to set XDG_DATA_DIRS to set a new theme path.

And second hook seems working.

[TheAssassin]

Is it possible to fix some of the paths e.g., using qt.conf? That file contains paths relative to the binary, and doesn't require any ugly environment hacks that might influence other components as well.

[abcfy2]

But I can't find how to set themeSearchPaths in qt.conf.

Set XDG_DATA_DIRS can solve this issue:

echo 'export XDG_DATA_DIRS="${APPDIR}/usr/share:${XDG_DATA_DIRS}:/usr/share:/usr/local/share"' > AppDir/apprun-hooks/xdg_data_dirs.sh

[TheAssassin]

Can't you use https://doc.qt.io/qt-5/qicon.html#setThemeSearchPaths in your code? That won't pollute your environment variables. You can fetch the mounted AppDir location from the environment ($APPDIR).

[abcfy2]

I just make a AppImage for https://github.com/c0re100/qBittorrent-Enhanced-Edition. So I think I can't modify the source code.

And I think set environment variable is the simplest way without change any codes.