joliclic blog

2.3.1 Maemo generalities

Maemo is a Linux, Debian based, distribution, for Mobile. And Firefox Mobile, aka Fennec, is available on this platform.
Fennec, like the desktop version of Firefox, is able to launch a XULRunner application via the -app argument.

So, a priori, we can launch any XULRunner applications. Of course, we should care of the specificities of mobile devices, small screen (but with high resolution), and touch screen. That's not the purpose of this howto. But as is, our app should work.

Because this platform is Debian based, we will distribute our app with a deb. We have just to adapt some parts of the previous chapter to the specificities of Maemo.

We can find some information in the Maemo Wiki.

2.3.2 Adapt the launcher

The change is that we invoke Fennec rather than Firefox.
The new launcher, myapp.sh:

#!/bin/sh

CUR_DIR=$(dirname $(readlink -f "$0"))

if [ -x /usr/bin/fennec ]; then
    /usr/bin/fennec -app "$CUR_DIR/application.ini" $@
elif [ -x /usr/bin/xulrunner ]; then
    /usr/bin/xulrunner "$CUR_DIR/application.ini" $@
else
    echo "Error: unable to find Fennec or XULRunner!"
fi

2.3.3 A new file system organization - Where place our app

On Maemo, due to the memory space on mobile devices, the applications should reside in the folder /opt/ rather than in /usr/lib/ or /usr/share/.

So, we will copy our app in /opt/myapp/.
A sub-directory would possible too, /opt/myorganization/myapp/ for example.

For the icons, we will use different dimensions than for the desktop, like Fennec does itself: a 26x26px png, a 40x40px png, and a 48x48 svg.
Their final locations change a little too, they must be placed in:

• /usr/share/icons/hicolor/26x26/hildon/myapp.png
• /usr/share/icons/hicolor/40x40/hildon/myapp.png
• /usr/share/icons/hicolor/scalable/hildon/myapp.svg

The location of the .desktop file change too, it must be placed into /usr/share/applications/hildon/ .

The .desktop file and the images are not so heavy, we can put them as is, but it should be possible to place them in our main app folder and use symbolic links too.

2.3.4 Additions to the .desktop file

Some information can be found in this page of the Maemo Wiki.

Some additional keys can be used in the desktop file. Not all that I add are documentated, but they seems to be used by a lot of programs, perhaps for some older version of Maemo.
Here's some lines added to our desktop file:

X-Icon-Path=/usr/share/icons
X-Window-Icon=myapp
X-Window-Icon-dimmed=myapp
X-Osso-Type=application/x-executable

2.3.5 Changes to the Debian files

To avoid to overwrite the generic deb created in the previous chapter, we will rename this new deb package for Maemo. We will use 'myapp-mobile'. To be consistent with the debhelper process, here the list of all this concerned changes:

• In the changelog file, the line myapp (1.0-1) unstable; urgency=low becomes myapp-mobile (1.0-1) unstable; urgency=low

• In the control file, the value for the Source and Package fields is changed to myapp-mobile

• The file myapp.links is renamed as myapp-mobile.links

Other changes to the control file:

According to this documentation, we must choose a Section in this list:

• user/desktop
• user/development
• user/education
• user/games
• user/graphics
• user/multimedia
• user/navigation
• user/network
• user/office
• user/science
• user/system
• user/utilities

We can add extra data to the control file, used to build the deb.
The first is XB-Maemo-Display-Name: MyApp .

The second is a base64 icon, used by the application manager of Maemo, XB-Maemo-Icon-26.

We will use a bash script to create this base64 value from the 48px png icon.

First we need the uuencode program, on debian/ubuntu:

apt-get install sharutils

then, we create a Bash script named build_base64.sh to convert a 48x48px png into the desired text value:

#!/bin/bash

set -e

# base64 conversion
uuencode -m icon48.png icon48.png > icon48.txt

# remove the first line (begin-base64 ...)
sed -i '1d' icon48.txt

# and the last line (====)
sed -i '$d' icon48.txt

# add 4 spaces at the beginning of each lines
sed -i "s/^/    /" icon48.txt

# and add a blank line at the end of the file
echo '' >> icon48.txt

You can find this script into the data/icons folder of the samples_chapter_2.tar.gz archive. To launch it (into the icons folder):

sh build_base64.sh

We can now use the content of icon48.txt as the value of XB-Maemo-Icon-26 in our control file.

2.3.6 Build the deb

And, that's all, we can create our deb like in the previous chapter.

I don't write here the build_maemodeb.sh script, it's almost the same as the one to build the generic debian package. You'll find it in the joined archive.

• cd samples_chapter_2

• sh ./build_maemodeb.sh

Note: I suppose in this howto that we don't have compiled code in our app.
If this is not the case, we must use scratchbox to compile, and we must use scratchbox to build the deb too!
And, like in the previous chapter, don't use the line Architecture: all in the control file.