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

ifndef _HELLOPART_H_
define _HELLOPART_H_

include <kparts/part.h>
include <kparts/factory.h>
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(){};

};

endif // _HELLOPART_H_

hello_part.cpp

include "hello_part.h"

include <kdemacros.h>
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()
{
}

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 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 have a .desktop file. This can be e.g. here:

$ ls /home/kde-devel/kde/share/kde4/services/kontact/
akregatorplugin.desktop     knotesplugin.desktop
akregatorplugin3.2.desktop  korganizerplugin.desktop
journalplugin.desktop       newstickerplugin.desktop
kaddressbookplugin.desktop  plannerplugin.desktop
karmplugin.desktop          specialdatesplugin.desktop
kmailplugin.desktop         summaryplugin.desktop
kmobiletools.desktop        todoplugin.desktop
knodeplugin.desktop         weatherplugin.desktop

You will also need your plugin, maybe here:

$ find /home/kde-devel/kde/lib/ -iname "karmpart*"
/home/kde-devel/kde/lib/kde4/karmpart.so

You will also need to create a subclass of Kontact::Plugin

Development/Tutorials/Writing kontact plugins