Introduction to Application Development in Python and Gtk+ / Hildon @ Maemo 5

Introduction to Application Development in Python and Gtk+ / Hildon @ Maemo 5 + my very own experience by Amanda Lam Hong Kong Maemo / Moblin / MeeGo User Group

Self Introduction
BEng Computer Systems Engineering, University of Warwick, UK
Technical Writer of a popular local website company
Founder of the Hong Kong Maemo / Moblin / MeeGo User Group @ facebook
Executive Committee Member and Podcaster of the Hong Kong PDA User Group (HKPUG)
Voluntary News Editor of UMPCFever.com / Digital.XY.HK
Author of the first Maemo 4.1 and Maemo 5 Traditional Chinese Language Pack
Application Developer of:
EeeToggle for Windows
eSpeak GUI Client for Maemo 5
Stroke Order Chinese Input Method ( 筆劃輸入法 ) for Maemo 5

Maemo Devices
Nokia Internet Tablets:
Nokia 770 Maemo 1.x/OS2005 Maemo 2.x/OS2006
Nokia N800 & N810 Maemo 3.x / “Bora” / OS2007 Maemo 4.0 / “Chinook” / OS2008 Maemo 4.1 / “Diablo” / OS2008
Nokia N900 Maemo 5 / “Fremantle” / OS2009
myInteractiveDevice (myID)
Maemo 4.x Compatible
ZhongYi 眾一 S101
Maemo 4.x Compatible

Maemo’s Application Frameworks
Maemo 1.x – 4.x
Based on the Gtk+ / Hildon application framework
Maemo 5
Based on the Gtk+ / Hildon application framework
Support of Qt 4.5 since PR1.0
Support of Qt 4.6 since PR1.2
i.e. ALL existing Maemo devices run Gtk+ and Hildon applications!

So, what is Gtk+?
Highly usable, feature rich toolkit for creating graphical user interfaces which boasts cross platform compatibility and an easy to use API.
Windows
Buttons
Menus
Status Bars
Dialog boxes
… many other GUI controls
Written in C.
Provide bindings to other programming languages.
Based on 4 libraries:
GLib : Low-level stuffs such as data structures, portability wrappers, event loop, threads, dynamic loading and an object system
Pango : layout and rendering of text with an emphasis on internationalization.
Cairo : 2D graphics with support for multiple output devices
ATK : set of interfaces providing accessibility

Where did Gtk+ come from?
Originated from the GIMP (GNU Image Manipulation Program) project by Spencer Kimball and Peter Mattis, started in 1995
Initially, based on Motif…
Not good enough!
So…
Rewrote their own GUI toolkit – Gtk
Released since GIMP 0.60
Renamed to Gtk+ since GIMP 0.99

Language Bindings supported by Gtk+
Gtk+ is written in C
Bindings are provided for programmers of other programming languages
Official bindings include: C++, Vala, Ruby, Python, Java, .Net, PHP and Perl.

Who use Gtk+?
Environments
GNOME, Xfce, LXDE…
Access Linux Platform (ALP)
Moblin / Maemo
Applications
AbiWord
Gnumeric
Midori
Evolution

Then, what is Hildon?
Application framework developed by Nokia
Now part of GNOME
Was used in Nokia Internet Tablet series and the Ubuntu Mobile and Embedded Edition
Depends on Gtk+ (GUI components), GConf (settings) & libcanberra (sound) libraries
Application Manager, Control Panel
Desktop, Widgets
Finger-friendly GUI components for Mobile Devices

Where Hildon sits in the Maemo Architecture?

Hildon 2.2 UI Components

Mixed use of Hildon and Gtk+ UI Components in Maemo
Most Hildon classes are inherited from Gtk+ classes
You can place both Gtk+ and Hildon UI components to your applications
… but, be aware of UI styles and user experience!

What programming languages can I use to develop Maemo applications?
C & C++ (GCC 4.2)
Python 2.5.4
PHP 5
Ruby 1.8
Java (OpenJDK 1.8.x)

I use Python. But why Python?
Because…
I am C-phobic!
I am just a beginner of Linux application development
Python syntax is simple, code is fairly readable
Interpreter; easy to debug
Can be imperative, object-oriented, or functional
Dynamic types
Automatic memory management
Works well with Gtk+ and Hildon frameworks
Many code examples
Many existing Maemo applications are developed in Python
Code and run directly on my Internet Tablets!

Little History of
Since 1989
By Guido van Rossum , a Dutch computer programmer, now a Google employee
Successor to the ABC programming language
Vision:
an easy and intuitive language just as powerful as major competitors
open source, so anyone can contribute to its development
code that is as understandable as plain English
suitability for everyday tasks, allowing for short development times

Maemo Applications written in Python
gPodder Podcast Client
Gonvert
Hermes
Panucci player
PyGTKEditor
Witter
Zoutube

How does Python code look like?

Let’s run the Hello World program!

Class Definition Example

My Maemo Applications
Written in Python and Gtk+/Hildon, of course.
Support both landscape and portrait mode.
UI Internationalization.
eSpeak GUI Client
Provides a GUI for the eSpeak text-to-speech CLI utility
Stroke Order Input Method 筆劃輸入法
As the name suggests!

eSpeakGUI Client: UI Components A set of hildon.PickerButtons in a gtk.HBox A set of hildon.GtkButtons in a gtk.VBox hildon.TextView in a hildon.PannableArea hildon.AppMenu A set of hildon.GtkButtons in a gtk.HBox

eSpeakGUI Client: UI Components hildon.TouchSelector

eSpeakGUI Client: How does it speak?
eSpeak is an open-source, command-line Text-to-Speech utility
Works like this…
espeakcmd = "espeak -v " + currentlang + " -a " + currentAmp + " -p " + currentPitch + " -s " + currentSpeed + " -g " + currentWordGap + " "" + textresult + "" &" os.system(espeakcmd)
Available in Maemo Extras Repository
The GUI client simply creates a command line to call the espeak utility via the os.system() method.
Argument values obtained from
Selected values of the hildon.PickerButtons
Text to be spoken from the hildon.TextView

eSpeakGUI Client: Demonstration

Stroke Order Chinese Input Method: UI Components hildon.StackWindow hildon. TouchSelector hildon.TextView in a hildon.PannableArea gtk.Label gtk.Label in hildon.PannableArea hildon.TextView hildon.GtkButtons in HBoxes and VBoxes hildon.GtkButtons in HBoxes and VBoxes hildon.GtkButton hildon.GtkButtons in a VBox hildon.AppMenu hildon.AppMenu

Stroke Order Chinese Input Method: UI Components hildon.AppMenu containing hildon.GtkButtons

Stroke Order Chinese Input Method: The Use of
Characters and associated phrases are stored in a SQLite 3 database.
Why SQLite 3?
Full Unicode Support
Native Python API
Lightweight, and, FAST!
It’s built-in in N900!

Stroke Order Chinese Input Method: Accessing C-compiled libraries directly
Not all features are available via bindings
You may import the ctypes library to get access to methods and properties in C-compiled libraries dynamically.
Example: Accessing the N900 Address Book:

Stroke Order Chinese Input Method: Demonstration

Get your hands dirty!
Q: What tools do you need to develop Python applications on the Maemo platform?
A: Python! And…
A plain-text editor!
Of course, there are other easy-to-use options too.

Glade – Gtk+ RAD tool
Drag-and-drop controls to build up a GUI app
Not aware of Hildon controls and libraries!
Require extra dependency on apps generated

Illumination Software Creator
Define variables, GUI components and action blocks visually.
Generate Python code for desktop and Maemo.
Generate Flex code for Adobe Flash apps.
Great app for building a brief prototype and then fine-tune your code later.
Available in Microsoft Windows, Mac OS X and various Linux distributions.

PyGtkEditor on Maemo
Open, edit, and run Python code directly on your Maemo device!
Support syntax highlighting and Hildon text completion.
Support other programming languages as well.
It itself is written in Python and Gtk+/Hildon!

I decide to develop Maemo apps in Python, do I still need Maemo SDK?
You can write Python programs that run on Maemo devices directly, without using the Maemo 5 SDK.
Transfer your Python scripts from your PC to your Maemo device.
Code directly on your device.
Run!
However, you need Maemo SDK if you:
Want to make use of the device simulator instead of testing your apps on real Maemo device.
Would like to package your Python apps.
Would like to upload your Python apps to the Maemo.org repositories.

Will my Python/Gtk+/Hildon apps work in MeeGo?
Well, maybe. Expect modifications though.
MeeGo is based on Qt instead of Gtk+/Hildon.
From MeeGo.com FAQ:
“ Will”. But when? We may get more clues in the forthcoming MeeGo Conference 2010.

MeeGo Architecture

Gtk+ Support in MeeGo Handset UX
Zwong tested a Gtk+ app on MeeGo Handset UX and confirmed that it somehow works partially. ( http:// zwong.de/?p =78 )

I want to develop apps for the MeeGo platform – shall I choose Gtk+, or Qt?
Of course, the answer is…
Qt!
Because the entire GUI of MeeGo is based on Qt components.
Python binding for Qt is also available: PyQt
Then why shall we still bother with Gtk+?
All Maemo devices up to today are based on Gtk+/Hildon.
The current release of the Chinese Input Method Engine “MSCIM” on N900 only supports Gtk+/Hildon apps, not Qt’s.
GNOME is available in nearly all mainstream Linux distributions.
Better to learn both!

References for you to get started
Python programming on Maemo
http:// wiki.maemo.org/PyMaemo
http:// wiki.maemo.org/PyMaemo/UI_tutorial
http:// pymaemo.garage.maemo.org /
http:// library.gnome.org/devel/pygtk/stable /
Hildon and Gtk+ Application Frameworks
http://maemo.org/api_refs/5.0/5.0-final/hildon/
http://www.forum.nokia.com/info/sw.nokia.com/id/eb8a68ba-6225-4d84-ba8f-a00e4a05ff6f/Hildon_2_2_UI_Style_Guide.html
http://www.forum.nokia.com/info/sw.nokia.com/id/019c2b31-3777-49a0-9257-970d79580756/Hildon_2_2_Widget_UI_Specification.html
Source Code of existing Maemo applications
http:// maemo.org /packages/

Thank you!
Questions are welcome.
Please join the Hong Kong Maemo / Moblin / MeeGo User Group at http://groups.to/hkmaemo/
Visit my blog at http://amanda_hoic.mysinablog.com/

References
Pictures and some text of this presentation were obtained from:
Gimp.org
Gnome.org
Gtk.org
Maemo.org
Meego.com
MyID.com.hk
Wikipedia.com
Zwong.de
Zy-mobile.com

Introduction to Application Development in Python and Gtk+ / Hildon @ Maemo 5

by Amanda Lam on Jan 31, 2011

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Introduction to Application Development in Python and Gtk+ / Hildon @ Maemo 5 — Presentation Transcript