Development/Tutorials

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Development/Tutorials


Tutorials are the fastest way of finding out what KDE will do for you, and how to do it. Here is a list of currently available tutorials for KDE4. Material for KDE3 and KDE2 is available on the bottom of this page.

Introduction To KDE 4 Programming

Are you interested in writing applications with KDE 4? This tutorial series is aimed at those completely new to KDE programming.

Hello World
A preliminary introduction to the very basics of KDE4 programming
Creating the Main Window
This tutorial shows you the magic of an application's most important thing: The main window.
Using KActions
How to add actions to the menus and toolbars.
Saving and Loading
Introduces the KIO library while adding loading and saving support to our application.
Command line arguments
Adds the ability to specify which file to open from the command line to our text editor.

Basics

Porting Your Application
Help Porting Applications from Qt3/KDE3 to Qt4/KDE4
Introduction to CMake
How to use the CMake build system used by KDE4.
Common Programming Mistakes
Various common mistakes made while developing Qt and KDE applications and how to avoid them.
Using Qt Designer to build user interfaces
How to create UI files with designer, and how to integrate them into a KDE program.
Creating Libraries to share code
How to add the library to the buildsystem and how to prepare the source code.
Session Management
Make your application aware of X sessions

Testing And Debugging

Debugging your application
Tips, tools and techniques to apply when debugging your KDE application
Writing Unittests for Qt4 and KDE4 with QTestLib (Original link)
Tutorial by Brad Hards that describes how to write unit tests using the QTestLib framework. It is presented as an example based tutorial, and is still under development.
Semi-automatic ways to detect code errors
Techniques you can use to detect errors in KDE code

Managing Configuration Data With KConfig

Introduction To KConfig
An overview of the KConfig classes and how to use them in your application code
Using KConfig XT
Tutorial on how to efficiently use the KConfig XT framework.
Updating KConfig Files
Tutorial on how to write an update script to keep changes in your application's config file format in sync with the user's already existing config file

Services: Applications and Plugins

Introduction to the Services Framework
An overview of the services framework in KDE and what it provides the application developer. Covers the system configuration cache (SyCoCa), the source data files and what the indexed information can be used for.
Finding Services Using Trader Queries
How to find services, such as plugins or mimetypes, that are indexed in the SyCoCa using Trader Query Syntax
Creating and Loading Plugins Using KService
Learn how to define custom plugin types, find installed plugins (including 3rd party plugins) and load them in an easy and portable fashion using KService.

Localization

See also Localization portal.

Introduction To Unicode
An introduction to what Unicode is as well as how to handle Unicode data in KDE applications.
Writing Applications With Localization In Mind
This tutorial covers what localization is, why it's important and how to ensure your application is ready to be localized. A must read for all application developers.
Avoiding Common Localization Pitfalls
There are several common mistakes that prevent applications from being properly localized. Find out what they are and how to easily avoid them in this tutorial.
Building KDE's Localization Module
Building and installing language support from KDE's localization (l10n) module is a good idea for those working on applications in the main KDE repository. Doing so will allow you to test your application in another language and spot problem areas. Learn how to do just that in this tutorial.
Incorporating i18n Into the Build System
Once your application is ready to be localized, the next step is to ensure that translation files are built automatically and kept up to date. This tutorial covers the necessary CMakeFiles.txt additions as well the process of distributing the resulting message catalogs with your application.
Common i18n Challenges and Solutions
This tutorial covers challenges that you may eventually run into such as translating handbooks and other data that exists outside of the source code, merging and handling obsolete .po files, dealing with freezes, coding in languages other than English and creating independent releases of or moving applications between KDE modules.
Semantic Markup of Messages
To ensure consistent presentation and more meaningful representations of messages in applications, semantic markup can be applied to messages marked for translation using the KUIT system. This tutorial describes how this system works.
Automated i18n Code Checking
The Krazy code checker scans KDE's code and reports common i18n mistakes.

Documentation

API Documentation
This tutorial explains how to document your APIs properly.
Man Pages
Writing and Generating Reference Manual Pages.

Application Automation and Scripting

D-Bus

Introduction to D-Bus
A straight-forward introduction to the core concepts in D-Bus from an application developer's perspective, this tutorial covers what D-Bus is and how it can be used by applications.
Accessing D-Bus Interfaces
A step-by-step guide to calling D-Bus methods and connecting to D-Bus signals using QtDBus.
Intermediate D-Bus
Tips to make use of QtDBus when faced with problematic real-world interfaces.
Creating D-Bus Interfaces
Learn how to expose functionality in your application by creating and using custom D-Bus interfaces. Covers generating the XML descriptions, instantiating interfaces at run time and setting up the build system with CMake.
D-Bus Autostart Services
Turn your application into a D-Bus autostart service with this tutorial. This D-Bus feature, also known as "D-Bus service activation", will ensure that even when your application isn't running that D-Bus calls made to it will work by relying on the D-Bus daemon itself to start your app if and when needed.
Porting from DCOP to D-Bus
Port your applications from DCOP to D-Bus with this handy guide.

Konqueror

Creating Konqueror Service Menus
This tutorial shows you how to create mimetype-specific actions in Konqueror's context menu (aka "servicemenus").

Kross

Introduction to Kross
An introduction to the Kross Scripting Framework.
Hello World
A first application with working kross code.
Calling Functions in Kross
Simple demonstration of calling scripting functions
Connecting Signals and Slots in Kross
Simple demonstration of connecting object signals with script slots
Scripts as Plugins with Kross
This tutorial provides a step-by-step introduction how to integrate scripts as plugins into a KDE application.
Placing script actions in your application menus
Simple demonstration on how to extend you application menus to execute script files.

KOffice Plugin Tutorials

KOffice Overview
This document shows an overview of the different KOffice plugin types and tells you what each of their purpose and strengths are. If you are new with KOffice plugins, this is the place to start.
Creating KOffice Flake Plugins
This tutorial shows you how you can build a plugin for KOffice applications to allow you embed content in ODF documents using Flake.
KWord Scripting
This tutorial shows how to script KWord with Python, Ruby or JavaScript using Kross.
KSpread Scripting
This tutorial shows how to script KSpread with Python, Ruby or JavaScript using Kross.

SuperKaramba

SuperKaramba Tutorial
This tutorial provides an overview of SuperKaramba, theme files and scripting with Python, Ruby and JavaScript.

System Activity

Writing script actions for the process's context menu
This tutorial shows how to add a context menu action to show custom information about a process.

Plugins and KParts

Writing kontact plugins
Kontact plugins are KParts. This tutorial describes how you can write one.
Using KParts
Learn how to load a KPart into an application window.
Writing Qt Designer Plugins
Add your widgets to Qt Designer and thus make them usable in UI files.

Search and Metadata

Strigi

Writing file analyzers
File analyzers extract data from files to display in the file dialogs and file managers. The data gathered this way is also used to search for files. KDE4 allows the use of multiple analyzers per file type. This tutorial describes how you can write new analyzers.

Nepomuk

Nepomuk Quickstart
How to use Nepomuk resources in a quick and painless way without much fuss.
RDF and Ontologies in Nepomuk
An introduction to RDF and the usage of ontologies in Nepomuk.
Data Layout in Nepomuk
An overview of which and how data is stored in Nepomuk.
Handling Resources with Nepomuk
Nepomuk is the KDE library which provides easy access to metadata in the Nepomuk system. Learn how to make your application create and read metadata using the Nepomuk system.
Using the Nepomuk Resource Generator
Nepomuk includes a resource generator which creates convenience classes for handling metadata.
Using the Nepomuk Query API
Starting with KDE 4.4 Nepomuk provides a desktop query API.
Advanced Queries
The real power of Nepomuk can only be exposed when performing fancy queries on the data repository. This tutorial provides an introduction to semantic and full text queries in Nepomuk.
The Nepomuk Server and the Architecture of the Nepomuk subsystem
The Nepomuk Server hosts the main Nepomuk data repository and can be accessed directly via a Soprano API.
Nepomuk Services
The Nepomuk Server manages a set of Nepomuk services.
  • Storage Service The probably most important service hosts the Nepomuk data repository using Soprano.
  • Ontology Loader Makes sure installed ontologies such as RDF, RDFS, NRL, or Xesam are loaded into the storage repository.
  • File Watch Service Monitors the file system for changes and updates the file resource paths and URIs in Nepomuk.
  • Strigi Service Controls Strigi, the file indexing tool which extracts metadata from files and stores it into the storage repository.
  • Query Service Provides persistant query folders.
Nepomuk Tips and Tricks
A set of tips and tricks for development with Nepomuk and Soprano. This is a must-read if you intend to use Nepomuk in your application or hack on it directly.

Hardware Awareness (Solid)

Introduction to Solid
An introduction to using the Solid hardware discovery and interaction system in KDE applications.
Accessing Network Information
How to use the Solid system to get information about the network

Privileged Applications (PolicyKit)

Introduction to PolicyKit
A straight-forward introduction to what PolicyKit is, and how it can be useful for your next application requiring super-user privileges or user authentication
Using the caller-helper model to perform actions as root
This tutorial will teach you how to get your application to perform some actions as root in a completely safe and easy manner, if the user is authorized to, by using PolicyKit and the caller-helper technique
Getting root privileges in KCM Modules
This tutorial will teach you how to create KCModules able to save settings as root

Multimedia (Phonon)

Phonon
How to start with the multimedia API
How to compile and use Phonon and its GStreamer backend on Linux using Qt 4.3.x
This article gives you a quick brief of how you can use checkout, compile Phonon and its GStreamer backend on GNU/Linux with just Qt 4.3.x. Towards the end, the article also describes how a developer can make use of Phonon to create simple audio and video players. You can read the article here. You can download the editable OpenDocumentText file from here.

Plasma

See Plasma tutorials.

Communication (Decibel)

Getting started with Decibel
This tutorial describes how to set up Decibel.
Handling TextChannels
This tutorial introduces the basics of handling incoming TextChannels by guiding you through building a simple text chat application.

Personal Information Management (Akonadi)

Using Akonadi in Applications
Displaying and modifying data provided by Akonadi
Developing Akonadi Resources
Akonadi Resources are agent programs which transport PIM data between Akonadi and a backend (files, servers, etc)
Using custom data types with Akonadi
Akonadi can handle arbitrary data as item payloads through the use of a plugin based serialization framework

Kate / Kwrite

Getting started with KTextEditor plugins
Creating your first KTextEditor plugin
Developing a plugin with configuration dialog
Adding a configuration dialog to the Time & Date example
A small Editor
Create a small application using KTextEditor

KDevelop

KDevelop-PG-Qt Introduction
Information on the KDevelop parser generator, useful for language plugins.

Printing

Hello World
Introduction to the KDE printing system
Print Dialog
Using the KDE print dialog

kioslaves

Collaboration

Open Collaboration Services (libattica)

Introduction to Attica
In this tutorial a simple widget showing information about a Person on the server is created.

Get Hot New Stuff

Get Hot New Stuff 3
How to use KHotNewStuff3 in your application.
Introduction to Get Hot New Stuff 2
A short tutorial about how to use KHotNewStuff2 in your application. Deprecated, use version 3
  • old links for KNS1 content:
Introduction to Get Hot New Stuff
An introduction to the developer-friendly network update system that allows KDE applications to fetch new application data at runtime in a user friendly manner.
KNewStuff Secure (Original Link)
Tutorial showing how to share resources in a secured way (KDE 3.4 and later). By András Mantia <amantia@kde.org>.

Goya

Introduction to Goya usage
An introduction for the Goya subsystem usage, which allows you to easily add widgets to your itemviews and connect their signals to your code, as they were real widgets.
Introduction to Goya usage (part 2)
The second part of the tutorial, with a slightly more complex example than the first part.

Other programming languages

Python

An Introduction to PyQt
Starting off
PyQt by Example
Another introduction to PyQt
PyKDE WebKit Tutorial
A simple web browser application in PyKDE
101 Introduction to signals and slots
A simple introduction to Qt's signal and slot architecture.
PyKDE DBus Tutorial
An introduction to DBus communication using PyKDE


Ruby

KDE Ruby Korundum tutorial
A ruby version of Antonio Larrosa Jiménez's KDE tutorial by Richard Dale. See the Ruby Developers Corner for Qt tutorials and other info.
Qt4 Ruby Tutorial
Nokia's fabulous introductory tutorial to Qt, translated to Ruby.
Creating a Plasma Widget in Ruby
Tutorial that shows how to create your first Plasma Applet using the Ruby language.
Developing Qt4 Applications using Qt Designer and Ruby on Kubuntu
Tutorial that shows how to design a simple User Interface in Qt Designer and then use the resulting widget in a Qt Ruby application we build from scratch.
Ruby-Qt/KDE Book
There is also an approach to create an Ruby-Qt/KDE Book under a free license. The content will be created in this wiki.

Shell

Shell Scripting with KDE dialogs (Original Link)
Tutorial by Brad Hards that describes how to use KDE dialogs in shell scripts with kdialog. It is presented as an example based tutorial.

Graphics Programming

QPainter Perfomance
Hints on avoiding common mistakes leading to poor performance when using QPainter

Using the KDE Games Libraries

KStandardGameAction
Using libkdegames to make your game fit the kdegames standard
Highscores
Implementing a simple highscore table into your game
Theme Selector
Using the libkdegames theme selection dialog
Palapeli Slicers
Creating a slicer plugin for Palapeli

KGLEngine

installation and your first KGLItem
start your first kglengine application
kglpong
Now use our knowledge to make a pong

KALEngine

Play hello word sound
Using KALEngine for games sound development using openAL
Play music
Using KALEngine to play music in a stream

Using the KDE PIM Libraries

iCalendar functionality
Using kcal to manage iCalendar files

Other tutorials

2D Plotting (KPlotWidget)

Using the KDE data-plotting widget
This tutorial introduces KPlotWidget, which is used for 2-D data plotting. It includes information on simple usage of the widget (including adding and modifying data sets, and customizing the plot axes and labels), and advanced customization (including extending the widget through sub-classing).

Spelling and Grammar Checking (Sonnet)

Adding spell-checking or grammar-checking to KDE applications
This tutorial introduces Sonnet and how one may use it to add language correction to your KDE application. Sonnet's auxiliary features shall be described in a separate tutorial.

Pixmap cache (KPixmapCache)

Using the KDE pixmap cache
This tutorial shows how to use KPixmapCache to cache e.g. pixmaps generated from SVGs or some data.

Using MarbleWidget (Marble)

Using MarbleWidget
This short tutorial describes how to use the MarbleWidget in your project

Using local SCM for KDE development

Using Git to develop for KDE
This tutorial shows how to use Git to develop for KDE

Kwin effect tutorial (blog)

blog by Martin Graesslin
This tutorial guides you through the development of a simple KWin effect

Implementing KSysGuard sensors and adding them

Development/Tutorials/Sensors
This tutorial shows how to write and KSysGuard sensor and connect it to the systray.

Runners

KDE2 and KDE3 Materials

KDE3 Tutorials
These tutorials cover topics related to KDE3.
KDE2 Tutorials
These tutorials cover topics related to KDE2.

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