Desktop menu, .desktop files and xdg-desktop-menu

What's the rela开发者_如何转开发tionship between .desktop files in the /usr/share/applications, the xdg-desktop-menu command and update-desktop-database command?

I'm trying to make a RPM that creates a desktop icon for my app. In the RPM, I install the vendor-appname.desktop file into /usr/share/applications. Then I have the following post-install script:

if [ -x "`which xdg-desktop-menu 2>/dev/null`" ]; then
    xdg-desktop-menu install $RPM_BUILD_ROOT/usr/share/applications/vendor-myapp.desktop
fi

if [ -x "`which update-desktop-database 2>/dev/null`" ]; then
    update-desktop-database &> /dev/null || :
fi

And the icon is not created. The icon IS created if I run the

xdg-desktop-menu install $RPM_BUILD_ROOT/usr/share/applications/vendor-myapp.desktop

command manually later on, as a non-root. If I do so as a root (which is, supposedly, how the RPM does it), the icon is not created. Also, I have a very strong suspicion that the update-desktop-database under if[] bit is not executed. It is executed when I manually run the whole if[] statement.

Fedora Linux with Gnome.

On Fedora, be sure of:

BuildRequires: desktop-file-utils
Requires(post): desktop-file-utils
Requires(postun): desktop-file-utils

Then (%{SOURCE1} is your desktop file):

%install
[...]
desktop-file-install                                    \
--dir=${RPM_BUILD_ROOT}%{_datadir}/applications         \
%{SOURCE1}
[...]

%post
update-desktop-database &> /dev/null || :

%postun
update-desktop-database &> /dev/null || :

If you install your own icon, you also need to update the icon cache, adding in the relative specfile sections:

%post
touch --no-create %{_datadir}/icons/hicolor &>/dev/null || :

%postun
if [ $1 -eq 0 ] ; then
    touch --no-create %{_datadir}/icons/hicolor &>/dev/null
    gtk-update-icon-cache %{_datadir}/icons/hicolor &>/dev/null || :
fi

%posttrans
gtk-update-icon-cache %{_datadir}/icons/hicolor &>/dev/null || :

Refs:

• http://fedoraproject.org/wiki/PackagingGuidelines#Desktop_files

• http://freedesktop.org/wiki/Software/desktop-file-utils

• http://fedoraproject.org/wiki/Packaging/ScriptletSnippets#Icon_Cache