Development/Tutorials/Writing kontact plugins

Introduction

Kontact is a KDE PIM (personal information management) framework that allows embedding several pim applications like kmail and korganizer as plugins into one window. Kontact plugins are KParts that get loaded at runtime. So, this is a good time to learn how to write a kPart... Read on.

Writing a KPart

We will write a "hello world"-KPart here. And we will write a MainWindow to hold this KPart. A KPart also gives you the flexibility to be integrated into kontact or konqueror, but we will do this later. So, the "hello world"-KPart only consists of a label "hello world". We chose a pushbutton because it is the easiest viewable thing to create. It does not trigger an action on your click. The following is what you do

• write a subclass mypart of KParts::Part
  • because setWidget is protected
  • use a Widget in it and use setWidget to get your widget into the KPart
• write a subclass mypartmainwindow of KParts::MainWindow
  • because createGUI is protected (and you may want createGUI later)
• write main.cpp
  • use new mypart(mw) to get your part into your main window

We will use 4 files to do this:

• CMakeLists.txt to ease building work
• mypart.h to declare our classes
• mypart.cpp to implement our classes

Create a directory hello in a fresh checkout of kdepim. In it, add the following files:

CMakeLists.txt

project(hello)
find_package (KDE4 REQUIRED)
INCLUDE_DIRECTORIES( ${KDE4_INCLUDES} . )

include_directories( ${KDE4_INCLUDE_DIR}/kcal ${CMAKE_SOURCE_DIR}/kresources/remote  )

set(hello_shared_SRCS 
	hello_part.cpp
 )


set(hellopart_PART_SRCS hello_part.cpp)

kde4_add_plugin(hellopart ${hellopart_PART_SRCS})

target_link_libraries(hellopart ${KDE4_KPARTS_LIBS} ${KDE4_KCAL_LIBS}  ${KDE4_KIO_LIBS} kdepim kcal_resourceremote)
if(X11_Xscreensaver_LIB)
	target_link_libraries(hellopart  ${X11_Xscreensaver_LIB} )
endif(X11_Xscreensaver_LIB)

install(TARGETS hellopart  DESTINATION ${PLUGIN_INSTALL_DIR})

install( FILES hello_part.desktop  DESTINATION ${SERVICES_INSTALL_DIR})

hello_part.h

1. ifndef _HELLOPART_H_
2. define _HELLOPART_H_

1. include <kparts/part.h>
2. include <kparts/factory.h>
3. include <QLabel>

/**

* This is a "Part".  It that does all the real work in a KPart
* application.
*/

class helloPart : public KParts::ReadWritePart {

 Q_OBJECT

 private:
   QLabel *mMainWidget;

public:

   helloPart(QWidget *parentWidget, QObject *parent, const QVariantList&);

   QLabel* MainWidget() { return mMainWidget; };

   virtual ~helloPart();
   bool openFile(){};
   bool saveFile(){};

};

1. endif // _HELLOPART_H_

hello_part.cpp

1. include "hello_part.h"

1. include <kdemacros.h>
2. include <kparts/genericfactory.h>

K_PLUGIN_FACTORY(helloPartFactory, registerPlugin<helloPart>();) // produce a factory K_EXPORT_PLUGIN(helloPartFactory("hello","hello") )

helloPart::helloPart( QWidget *parentWidget, QObject *parent, const QVariantList& )

   : KParts::ReadWritePart(parent)

{

 KGlobal::locale()->insertCatalog("hello");
 // we need an instance
 setComponentData( helloPartFactory::componentData() );

 mMainWidget = new QLabel();
 mMainWidget->setText("hello");
 setWidget( mMainWidget );

}

helloPart::~helloPart() { }

1. include "hello_part.moc"

hello_part.desktop

[Desktop Entry]
Name=Friendly Component
MimeType=text/calendar;
X-KDE-ServiceTypes=KParts/ReadOnlyPart,KParts/ReadWritePart
X-KDE-Library=hellopart
Type=Service

Compiling your KPart

To compile, link and install the code above, use

cmake . && make && make install

Now you can find your kpart in the local lib folder:

tweedleburg:~/svn/kdepim/hello # ll lib
total 468
-rwxr-xr-x 1 root root 471554 May 28 22:42 hellopart.so

And after compilation e.g. in /usr/local/lib/kde4/hellopart.so

And you can find your kpart in the services folder (${SERVICES_INSTALL_DIR} from CMakeLists.txt):

$ ll $(kde4-config --install services)hello*
-rw-r--r-- 1 root root 161 May 28 23:33 /usr/local/share/kde4/services/hello_part.desktop

Kontact integration

To integrate your KPart into kontact, you will need to create a subclass of Kontact::Plugin

So, go to your checkout of kdepim, create a folder kdepim/kontact/plugins/hello. Continue there.

CMakeLists.txt

include_directories(${CMAKE_SOURCE_DIR}/hello)

set(kontact_hello_PART_SRCS hello_plugin.cpp)

kde4_add_plugin(kontact_helloplugin ${kontact_hello_PART_SRCS})

kdepim4_link_unique_libraries(kontact_helloplugin ${KDE4_KDECORE_LIBS} kontactinterfaces)

install(TARGETS kontact_helloplugin  DESTINATION ${PLUGIN_INSTALL_DIR})

install(FILES helloplugin.desktop  DESTINATION ${SERVICES_INSTALL_DIR}/kontact)

hello_plugin.desktop

[Desktop Entry]
Type=Service
Icon=whatever
X-KDE-ServiceTypes=Kontact/Plugin,KPluginInfo

X-KDE-Library=kontact_helloplugin
X-KDE-KontactPluginVersion=7
X-KDE-KontactPartLibraryName=hellopart
X-KDE-KontactPluginHasSummary=false

X-KDE-PluginInfo-Name=kontact_helloplugin
X-KDE-PluginInfo-Version=0.1
X-KDE-PluginInfo-License=GPL
X-KDE-PluginInfo-EnabledByDefault=true

Comment=The friendly Plugin
Name=hello

hello_plugin.h

#ifndef HELLO_PLUGIN_H
#define HELLO_PLUGIN_H

#include <kontactinterfaces/plugin.h>
#include <kparts/part.h>

class HelloPlugin : public Kontact::Plugin
{
  Q_OBJECT

  public:
    HelloPlugin( Kontact::Core *core, const QVariantList & );
    ~HelloPlugin();

    virtual void readProperties( const KConfigGroup &config );
    virtual void saveProperties( KConfigGroup &config );

  private slots:
    void showPart();

  protected:
    KParts::ReadOnlyPart *createPart();
};

#endif

hello_plugin.cpp

#include "hello_plugin.h"

#include <hello_part.h>

#include <kontactinterfaces/core.h>
#include <kontactinterfaces/plugin.h>

#include <kactioncollection.h>
#include <kgenericfactory.h>
#include <kicon.h>
#include <kparts/componentfactory.h>

EXPORT_KONTACT_PLUGIN( HelloPlugin, hello )

HelloPlugin::HelloPlugin( Kontact::Core *core, const QVariantList & )
  : Kontact::Plugin( core, core, "Hello" )
{
  setComponentData( KontactPluginFactory::componentData() );
}

HelloPlugin::~HelloPlugin()
{
}

KParts::ReadOnlyPart *HelloPlugin::createPart()
{
  KParts::ReadOnlyPart *part = loadPart();

  connect( part, SIGNAL(showPart()), this, SLOT(showPart()) );

  return part;
}

void HelloPlugin::readProperties( const KConfigGroup &config )
{
  if ( part() )
  {
    helloPart *myPart = static_cast<helloPart*>( part() );
  }
}

void HelloPlugin::saveProperties( KConfigGroup &config )
{
  if ( part() )
  {
    helloPart *myPart = static_cast<helloPart*>( part() );
  }
}

void HelloPlugin::showPart()
{
  core()->selectPlugin( this );
}


#include "hello_plugin.moc"

See also

• http://api.kde.org/4.x-api/kdepim-apidocs/kontact/html/classKontact_1_1Plugin.html - The Kontact Plugin Interface documentation
• http://pim.kde.org/development/tutorials/creatingplugins.php - tutorial for KDE 3
• http://api.kde.org/4.x-api/kdelibs-apidocs/kparts/html/classKParts_1_1MainWindow.html - the mainwindow where you display your kpart in
• http://osdir.com/ml/python.pyqt-pykde/2005-09/msg00124.html