maemo.org - Talk - Linux Maemo Development Guide

EDIT:: Tested on latest Nokia SDK released on 23 June 2010

Hi.

I just thought I would create a quick guide to getting started in Maemo including setting up the environment, creating a "HelloWorld" program and running it on the Nokia N900.

Please free to add comments and I will edit this post to reflect all your comments and criticisms!

Tested on 32 bit Linux Mint 9 running on a Intel P4.

0. Remove Old SDK
Just in case there are no issues with two SDKs, remove the old SDK by running the SDKMaintenanceTool tool. This should be located as a menu item.

If you don't have it on your menu bar, you can find it in the install directory.

Once it has loaded, simply select the tab "Package Manager", select the option "Remove all components", then click "Next".

Now simply click "Uninstall" and Nokia SDK will be removed completely, and then click "Finish" to close the tool.

1. Installing QT SDK

Download the current Nokia QT SDK (released on 23 June 2010) from:

PHP Code:


		
			
http://www.forum.nokia.com/info/sw.nokia.com/id/e920da1a-5b18-42df-82c3-907413e525fb/Nokia_Qt_SDK.html

Then set permissions to execute by opening up a terminal window and typing:

Code:

chmod u+x Nokia_Qt_SDK_Lin32_offline_v1_0_en

Then execute by typing:

Code:

./Nokia_Qt_SDK_Lin32_offline_v1_0_en

If you get any errors, you may need to execute the file with root permissions. Simply type:

Code:

sudo ./Nokia_Qt_SDK_Lin32_offline_v1_0_en

Follow all the prompts and for simplicity sake, please select full install. You can remove old QT settings if you wish.

This make take a while... be patient!

2. Rebuild Qt Debugging Helper

Now Qt is installed, there is one important thing we need to do before we create a sample code.

We need to ensure that the debugging helpers are built.

Load Qt and go to:

Code:

Tools -> Options -> Qt4

Click on Qt for Fremantle PR1.2 Devices (Nokia Qt SDK) and then click on Rebuild.

You will find that the red cross is now a green tick.

Do the same for Simulator Qt for GCC (Nokia Qt SDK). Click OK to exit.

Next we need to configure the N900.

3. N900 setup

To make your life easier, you can add the Nokia N900 to Qt and use one click testing and deployment on the device itself.

You can visit http://wiki.maemo.org/MADDE/QtCreato...tion_for_linux for the USB method of connection, but as I dislike wires, I will be using the Wifi method.

First we need to prepare the device:

Make sure you have the latest firmware installed. To check the latest firmware, please go to:

Code:

Menu -> Settings -> About Product

Ensure you have:

HTML Code:

Version: 10.2010.19-1.203.1

Make sure you have the extras repository setup.

Load up the App Manager:

Code:

Menu -> App Manager

Select the Application Manager title and select Application Catalogues, check to ensure you have maemo.org or maemo Extras.
If you have both, then select maemo Extras and disable it.

Open up maemo.org, ensure it has the following:

Code:

Catalog name: maemo.org

Web address: http://repository.maemo.org/extras/

Distribution: fremantle-1.2

Components: free non-free

Now select Download -> Development -> mad-developer

This will talk to Qt and allow it to deploy code to the N900.

Install the client. Note, you will be asked for a new root password, PLEASE DO NOT FORGET THIS!

4. Add the N900 to Qt

If Mad Developer is not loaded, load it up.

It should display your IP address on wlan0.

In Qt, goto:

Code:

Tools -> Options -> Projects -> Maemo Device Configurations

Click the Add button

To add the N900, populate the following fields:

Code:

Name: Nokia N900

Device Type: Select Remote device

Authentication Type: Select Password

Host Name: Enter the IP address as shown on the N900

Username: developer

Password: Click on the "Developer Password" on the N900 and enter this here

Now click on "Test" to see if everything works.

You should be presented with the following:

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Device configuration successful.

Hardware architecture: armv7l

Kernel version: 2.6.28-omap1

List of installed Qt packages:

    libqt4-core 4.6.2

    libqt4-dbus 4.6.2

    libqt4-gui 4.6.2

    libqt4-maemo5 4.6.2

    libqt4-maemo5-core 4.6.2

    libqt4-maemo5-dbus 4.6.2

    libqt4-maemo5-gui 4.6.2

    libqt4-maemo5-maemo5 4.6.2

    libqt4-maemo5-xml 4.6.2

    libqt4-multimedia 4.6.2

    libqt4-network 4.6.2

    libqt4-opengl 4.6.2

    libqt4-phonon 4.6.2

    libqt4-sql 4.6.2

    libqt4-sql-sqlite 4.6.2

    libqt4-svg 4.6.2

    libqt4-webkit 4.6.2

    libqt4-xml 4.6.2

    libqt4-xmlpatterns 4.6.2

Click close to close the message box. You will need to enter a new password each time you load Mad-Developer.

Therefore, we should deploy a key to ensure we can simply load Mad-Developer on the N900 and start using it.

Note: Encrypted keys are not supported.

Click on Generate SSH Key.

A new box will open. Select Key Size 4096 and then click Generate SSH Key.

Once the key has been generated, click on Save Public Key and then click on Save Private Key.

Ensure you save them somewhere safe. Click Close to go back to the Maemo Device Configuration Screen.

If you need to change the [/B]Private Key file[/B] location, change the "Authentication Type" to Key, then click Browse button at the bottom next to Private Key and select the private key you just generated.

Now change the Authentication Type back to Password and click on "Deploy Public Key". A box will appear asking you to select the public key. Select the one you just saved and click Open.

You should revieve the message "Key was successfully deployed"

Now change the Authentication Type to "Key" and click Test to ensure it connects successfully.

Click Ok to close that screen and open the main screen up.

Now we can create out first "Hello World Program"

5. Hello World

Let create a push button when pressed will pop up a message on the screen saying "Hello World!"

First ensure you are on the Welcome screen of Qt.

Click on Create Project.

Select Mobile Qt Application, then click on Choose

Set the name as HelloWorld and click Next.

In the next screen, ensure you select both Qt for Fremantle PR1.2 Devices (Nokia QT SDK) and Simulator QT for GCC (Nokia Qt SDK) and then click Next.

Click Next again on the Class Information screen and then click on Finish.

Now by default, you should be in Design mode.

Drag a "Push Button" to the main window.

Right-Click on the Button and click "Go to slot...". Select the Clicked() and then click on OK.

You may receive an error about not being able to find/add a slot.

I believe this may be a bug. Rebuilding will not help. To solve this, simply click OK to close the error box.

On the bottom left hand side, there should be button labelled Debug, click this once and then Select the Top one, Maemo. Wait for a few seconds so that the scanning/parsing finished.

Then click back on the Qt Simulator.

Now you should be able to right click on the new button and select Go to slot... and then Clicked() and then OK.

No add the following to the MainWindow::on_pushButton_clicked() section so that it looks like the following:

Code:

void MainWindow::on_pushButton_clicked()

{

    QMessageBox msgBox;

        msgBox.setText("Hello World!");

        msgBox.exec();

}

Ensure you only paste the bold items into the section.

Now we simply need to add the header, so go right to the top of the editor and add the following bold line:

Code:

#include "mainwindow.h"

#include "ui_mainwindow.h"

#include <QMessageBox>

That is all we need to do.

To run on the Desktop simulator, simply click on the Run button (the first big green arrow on the left. You will be prompted to save, simply click Save All.

After a few seconds, you should receive a nice image of the N900 with a button. Click the button and it should say Hello World!.

To run it on the N900, simply click the Debug button and then select the Maemo option. Now click the green run button or hold CTRL+R.

The application should now be running on your Nokia N900.

Some people may prefer to use Scratchbox, so the following will help you setup Scratchbox and create a "Hello World" program.

1. Install Scratchbox

Scratchbox is, taken from the scrachbox website:

Quote:

Scratchbox is a cross-compilation toolkit designed to make embedded Linux application development easier. It also provides a full set of tools to integrate and cross-compile an entire Linux distribution.

First, you will need to ensure that xserver-xephyr is installed on your system. Xephyr is an X server that can be run inside another X server. Xephyr will create a window that scratchbox can populate with the N900 emulator or "Window".

Use your package manager or control panel or what ever you use to manage installed programs to install Xephyr. For example, in Linux Mint, I can use the "Package Manager".

Once installed, download the SDK python script and install it. Note, if the script fails to run, it is because you do not have Python installed. Again, go to your package manager and install Python. However, on Linux Mint, when I ran the script, it installed Python on its own.

Download from http://repository.maemo.org/stable/5...-wizard_5.0.py

Open up a new terminal and run the following:

First we make it executable:

Code:

chmod a+x maemo-sdk-install-wizard_5.0.py

Then run as root:
If you use Ubuntu:

Code:

sudo ./maemo-sdk-install-wizard_5.0.py

or if you use Debian:

Code:

su -c ./maemo-sdk-install-wizard_5.0.py

or if the above does not work, try:

Code:

su

enter your root password and then

Code:

./maemo-sdk-install-wizard_5.0.py

A Scratchbox install window should appear, follow the options untill you get to the installing now part.

Note, this will take a long time as you need to download a lot of data ~600mb. You best grab a coffee!

If Scratchbox fails to install due to "too many errors", the following should work. There is a known bug in the installer so this is a quick workaround:

Open up a terminal window and edit the following file:

Code:

/etc/sysctl.conf

Add the line to the bottom of the file:

Code:

vm.mmap_min_addr = 0

Save and exit

Then run:

Code:

sudo sysctl -p

No try running scratchbox again:

Code:

sudo ./maemo-sdk-install-wizard_5.0.py

It should continue from where it left off.

2. Update Scratchbox

Hopefully Scratchbox installed successfully. Now we just need to update Scratchbox and add all the Qt libraries so we can run Qt apps.

Open up a terminal window and login to Scratchbox:
login to scratchbox:

Code:

/scratchbox/login

Hopefully you will get the following prompt:

PHP Code:


		
			
user@linuxmint ~/Desktop $ /scratchbox/login



Welcome to Scratchbox, the cross-compilation toolkit!



Use 'sb-menu' to change your compilation target.

See /scratchbox/doc/ for documentation.



[sbox-FREMANTLE_X86: ~] >

First, we need to add the extras repositories:

Code:

vim /etc/apt/sources.list

Now use the arrow keys to get to am empty spot, press the i key which will turn the mode to insert and type out the following:

Code:

#Extras

deb http://repository.maemo.org/extras/ fremantle free non-free

deb-src http://repository.maemo.org/extras/ fremantle free

If you make a mistake, hit the Escape key and type :q! and hit enter and vim will quit without saving. Once your happy you have typed everything correctly, hit Escape and :w and enter to save the file. Then to quick, press Escape and then type :q

You can now go ahead an update apt’s local cache:

Code:

fakeroot apt-get update

Now we want to check we have the latest distribution. Type:

Code:

fakeroot apt-get dist-upgrade

Now Scratchbox is updated, so we need to add the Qt libraries, type:

Code:

fakeroot apt-get install libqt4-gui libqt4-dev

Exit Scratchbox by typing exit and close your terminal.

We are now ready to try out Scratchbox to see if it run the N900 "emulator".

By default the SDK requires a Xephyr window, simply double clicking on the Desktop icon will not work.

So lets edit that script so it creates the window for us so we only have one icon we need to double click.

Edit the /usr/local/bin/start_xephyr.sh file and add code to run a window. This should be a single line only, sorry but the forum wraps the line:

Code:

(Xephyr :2 -host-cursor -screen 800x480x16 -dpi 96 -ac -keybd ephyr,,,xkbmodel=evdev) &

So the file becomes:

Code:

#!/bin/sh

# Automatically created by Maemo 5.0 SDK Installer

(Xephyr :2 -host-cursor -screen 800x480x16 -dpi 96 -ac -keybd ephyr,,,xkbmodel=evdev) &

(Xephyr :2 -host-cursor -screen 800x480x16 -dpi 96 -ac -kb; newgrp sbox <<'END'

/scratchbox/login af-sb-init.sh stop

END

) &

newgrp sbox <<'END'

sleep 3

/scratchbox/login sb-conf select FREMANTLE_X86

/scratchbox/login af-sb-init.sh restart

END

Save and double click the SDK icon and you should now have working window.

Now you are ready to to try your hello world program!. Close any windows that are still open.

3. Hello world

The Nokia SDK will create a windows which will show us a N900 window. We will still need to use a separate terminal to "inject" our code.

So lets begin by creating the basic hello world program. On your desktop, you should find a sbhome icon. Double clicking this will take you to the /scratchbox/users/username/home/username

Essentially, /scratchbox contains all of maemo so it is the "root" of the phone.

Anyway, enter the sbhome and create a new directory called "HelloWorld". I believe in most linux window managers, you can right click and then Create Folder.

Now open an editor of some sort, example, GEdit and paste the following code:

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#include <QApplication>

#include <QLabel>

int main(int argc, char *argv[])

{

QApplication app(argc, argv);

QLabel *label = new QLabel("Hello World");

label->show();

return app.exec();

}

You will need to pay special attention to the quotes. It needs to be ASCII quotes. If you have an option, select ASCII as the encoding format. Also, make sure there is no extra spacing left at the end of the code. Save it in the HelloWorld folder as HelloWorld.cpp

Now lets compile this.

First, double click the Maemo5 SDK icon to load up an emulator.

Then open up a terminal and login to scratchbox:

Code:

/scratchbox/login

By default,, you should be in the same directory as sbhome, so if you type

Code:

ls

and enter, you should see the following:

Code:

[sbox-FREMANTLE_X86: ~] > ls

HelloWorld  maemo-sdk-rootstrap_5.0_10.2010.19-1_armel.tgz

MyDocs      maemo-sdk-rootstrap_5.0_10.2010.19-1_i386.tgz

[sbox-FREMANTLE_X86: ~] >

Now change to HellowWorld directory:

Code:

cd HelloWorld

Check to see your HellowWorld.cpp file is there:

Code:

[sbox-FREMANTLE_X86: ~] > cd HelloWorld

[sbox-FREMANTLE_X86: ~/HelloWorld] > ls

HelloWorld.cpp

[sbox-FREMANTLE_X86: ~/HelloWorld] >

Now to compile, simply type the following:

Code:

qmake -project

Then:

Code:

qmake

Then finally:

Code:

make

The output should be something like the following:

Code:

[sbox-FREMANTLE_X86: ~/HelloWorld] > qmake -project

QFileInfo::absolutePath: Constructed with empty filename

[sbox-FREMANTLE_X86: ~/HelloWorld] > qmake

[sbox-FREMANTLE_X86: ~/HelloWorld] > make

g++ -c -pipe -O2 -Wall -W -D_REENTRANT -DQT_NO_DEBUG -DQT_GUI_LIB -DQT_CORE_LIB -DQT_SHARED -I/targets/FREMANTLE_X86/usr/share/qt4/mkspecs/linux-g++ -I. -I/targets/FREMANTLE_X86/usr/include/QtCore -I/targets/FREMANTLE_X86/usr/include/QtGui -I/targets/FREMANTLE_X86/usr/include -I. -I. -o HelloWorld.o HelloWorld.cpp

g++ -Wl,-O1 -Wl,-rpath,/usr/lib -o HelloWorld HelloWorld.o    -L/usr/lib -lQtGui -L/usr/lib -L/usr/X11R6/lib -lQtCore -lpthread 

[sbox-FREMANTLE_X86: ~/HelloWorld] >

To load our new program up, type the following and hit enter:

Code:

run-standalone.sh ./HelloWorld

Now click on the emulator window, which should show the Hello World program.