Developing with C++ and Qt

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NOTE: This article is way to unify community experience, trip and ticks in order to develop C++ application based on the QT framework. It's actually incomplete and may be wrong in several parts, please fix and improve!


Contents

Introduction

extracted from wikipedia:

Qt is a cross-platform application development framework, widely used for the development of GUI programs, and also used for developing non-GUI programs such as console tools and servers. Qt is most notably used in KDE, Opera, Google Earth, Skype, Qtopia, Photoshop Elements, VirtualBox and OPIE. It is produced by the Norwegian company Trolltech. Nokia acquired Trolltech on January 28, 2008.

Applications using Qt should run on 2008.x, FSO/SHR, and Qtopia from Trolltech (on this firmware alternative widget toolkits, as gtk+, actually do not work, as they need an X server). This make Qt a good choice to start developing new applications for the Openmoko world.

Developing with Trolltech/Qtopia

Trolltech provides good SDK and documentation. You can download the official SDK here.

It's a VMware based virtual machine you can run with the free vmplayer. This is a ready to go solution.

If you prefer to dirty your hands and to have a SDK on your host linux system, you may build your Qtopia image, and SDK manually:

TBD, actually refer to the excellent article at [1]

n.b. this methods will build applications suitable only for the Qtopia firmware

Developing with FSO based images

You have to prepare an oe build tree using the makefile at http://downloads.freesmartphone.org, read Mokomakefile article, install needed tools and type the following commands as a normal unprivileged user:

mkdir fso
cd fso
wget http://downloads.freesmartphone.org/Makefile
make setup
cd fso-unstable
make create-topdir

now you have to comment the line:

PREFERRED_VERSION_qt4-x11-free ?= "4.3.3"

in the file

openembedded/conf/distro/include/preferred-om-2008-versions.inc

This is necessary to build qt 4.4.1 and to fix a problem in the oetree.

FIXME, is it possible to use a local .conf file to set a correct preferred version, but how unset it definitively?

You are now ready to build Qt by typing:

. setup-env
bitbake qt4-x11-free

After that you'll have staging Qt arm libraries and x86 tools to build your application, so you'll have to create a somename.bb file.

A simple skeleton may be:

SECTION = "x11/libs"
PRIORITY = "optional"
HOMEPAGE = "http://yourproject.org"
LICENSE = "GPL QPL"
DEPENDS = "qt4x11"

SRC_URI = "svn://your_svn_server/some_path;module=trunk;proto=https;rev=xxx"

S = "${WORKDIR}/trunk"

inherit qt4x11

do_configure() {
        ${OE_QMAKE_QMAKE}
}

do_compile() {
        oe_runmake
}

do_install() {
        install -d ${D}${bindir}
        install -m 0755 your_application_executable ${D}${bindir}
}

ALLOW_EMPTY = ""
RDEPENDS_${PN} = "qt4-x11-free"
FILES_${PN}  =  "${bindir}/your_application_executable"

This assumes you have an svn server for your sources, if not, SRC_URI has to be modified (TBD). You can now do:

bitbake path_to/myapplication.bb

If it compiles fine, you'll find in the tmp/deploy/glibc/ipk/armv4t an ipk package of your application, you may copy it to the device and install usually with opkg.

You may be able to use the FSO framework using the QT dbus module.

Developing for 2008.x

On 2008.x qt library is already shipped in /opt/Qtopia, but there is no staging files you may use to build application against it. This is in discussion, and actually you may use some workarounds.

The first is bitbaking qt4-x11-free with the official Mokomakefile, and proceed as on the FSO section, but you have to load the correct libraries with LD_LIBRARY_PATH before running your application.

The second is to use build tools in the work section of the oetree as they whould be in the staging area (TBD)

To interact with the middleware you should use Qtopia library (note not qt library), but this is undocumented/untested/unconfirmed.

Personal tools
NOTE: This article is way to unify community experience, trip and ticks in order to develop C++ application based on the QT framework. It's actually incomplete and may be wrong in several parts, please fix and improve!


Introduction

extracted from wikipedia:

Qt is a cross-platform application development framework, widely used for the development of GUI programs, and also used for developing non-GUI programs such as console tools and servers. Qt is most notably used in KDE, Opera, Google Earth, Skype, Qtopia, Photoshop Elements, VirtualBox and OPIE. It is produced by the Norwegian company Trolltech. Nokia acquired Trolltech on January 28, 2008.

Applications using Qt should run on 2008.x, FSO/SHR, and Qtopia from Trolltech (on this firmware alternative widget toolkits, as gtk+, actually do not work, as they need an X server). This make Qt a good choice to start developing new applications for the Openmoko world.

Developing with Trolltech/Qtopia

Trolltech provides good SDK and documentation. You can download the official SDK here.

It's a VMware based virtual machine you can run with the free vmplayer. This is a ready to go solution.

If you prefer to dirty your hands and to have a SDK on your host linux system, you may build your Qtopia image, and SDK manually:

TBD, actually refer to the excellent article at [1]

n.b. this methods will build applications suitable only for the Qtopia firmware

Developing with FSO based images

You have to prepare an oe build tree using the makefile at http://downloads.freesmartphone.org, read Mokomakefile article, install needed tools and type the following commands as a normal unprivileged user:

mkdir fso
cd fso
wget http://downloads.freesmartphone.org/Makefile
make setup
cd fso-unstable
make create-topdir

now you have to comment the line:

PREFERRED_VERSION_qt4-x11-free ?= "4.3.3"

in the file

openembedded/conf/distro/include/preferred-om-2008-versions.inc

This is necessary to build qt 4.4.1 and to fix a problem in the oetree.

FIXME, is it possible to use a local .conf file to set a correct preferred version, but how unset it definitively?

You are now ready to build Qt by typing:

. setup-env
bitbake qt4-x11-free

After that you'll have staging Qt arm libraries and x86 tools to build your application, so you'll have to create a somename.bb file.

A simple skeleton may be:

SECTION = "x11/libs"
PRIORITY = "optional"
HOMEPAGE = "http://yourproject.org"
LICENSE = "GPL QPL"
DEPENDS = "qt4x11"

SRC_URI = "svn://your_svn_server/some_path;module=trunk;proto=https;rev=xxx"

S = "${WORKDIR}/trunk"

inherit qt4x11

do_configure() {
        ${OE_QMAKE_QMAKE}
}

do_compile() {
        oe_runmake
}

do_install() {
        install -d ${D}${bindir}
        install -m 0755 your_application_executable ${D}${bindir}
}

ALLOW_EMPTY = ""
RDEPENDS_${PN} = "qt4-x11-free"
FILES_${PN}  =  "${bindir}/your_application_executable"

This assumes you have an svn server for your sources, if not, SRC_URI has to be modified (TBD). You can now do:

bitbake path_to/myapplication.bb

If it compiles fine, you'll find in the tmp/deploy/glibc/ipk/armv4t an ipk package of your application, you may copy it to the device and install usually with opkg.

You may be able to use the FSO framework using the QT dbus module.

Developing for 2008.x

On 2008.x qt library is already shipped in /opt/Qtopia, but there is no staging files you may use to build application against it. This is in discussion, and actually you may use some workarounds.

The first is bitbaking qt4-x11-free with the official Mokomakefile, and proceed as on the FSO section, but you have to load the correct libraries with LD_LIBRARY_PATH before running your application.

The second is to use build tools in the work section of the oetree as they whould be in the staging area (TBD)

To interact with the middleware you should use Qtopia library (note not qt library), but this is undocumented/untested/unconfirmed.