Revision as of 20:38, 29 June 2011

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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 use KParts that get loaded at runtime. So, this is a good time to learn how to write a kPart. The "hello world" kontact plugin we will be writing here will look like this:

Writing a KPart

We will write a "hello world"-KPart here. And you will learn how to hold it in a MainWindow. 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 label because it is the easiest viewable thing to create. It does not trigger any action. 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_
</code>
 
== hello_part.cpp ==
 
<syntaxhighlight lang="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"
</code>
 
== hello_part.desktop ==
 
<pre>
[Desktop Entry]
Name=Friendly Component
MimeType=text/calendar;
X-KDE-ServiceTypes=KParts/ReadOnlyPart,KParts/ReadWritePart
X-KDE-Library=hellopart
Type=Service
</pre>
 
= 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 [http://api.kde.org/4.x-api/kdepim-apidocs/kontact/html/classKontact_1_1Plugin.html Kontact::Plugin]
 
So, go to your checkout of kdepim, create a folder kdepim/kontact/plugins/hello. Continue there. We will make a shared object file kontact_helloplugin.so and a file hello_plugin.desktop. Those files will be the kontact plugin and tell kontact at runtime ''which'' kPart to load (hello_plugin.desktop) and ''how'' (kontact_helloplugin.so).
 
== Files ==
=== CMakeLists.txt ===
 
<pre>
include_directories(${CMAKE_SOURCE_DIR}/hello)
 
set(kontact_hello_PART_SRCS hello_plugin.cpp)
 
kde4_add_plugin(kontact_helloplugin ${kontact_hello_PART_SRCS})
 
target_link_libraries(kontact_helloplugin ${KDE4_KDEUI_LIBS} kontactinterfaces)
 
install(TARGETS kontact_helloplugin  DESTINATION ${PLUGIN_INSTALL_DIR})
 
install(FILES hello_plugin.desktop  DESTINATION ${SERVICES_INSTALL_DIR}/kontact)
</pre>
For me kontact_helloplugin is a binary residing in /usr/local/lib64/kde4/kontact_helloplugin.so. hello_plugin.desktop is installed to /usr/local/share/kde4/services/kontact/hello_plugin.desktop.
 
=== hello_plugin.desktop ===
 
The file kontact/plugins/hello/hello_plugin.desktop tells the kontact plugin which kPart to load. In this case, it is hellopart.
 [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 ===
 
<pre>
#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
</pre>
 
=== hello_plugin.cpp ===
 
<pre>
#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"
</pre>
 
== install your plugin ==
To compile, link and install your plugin, change kdepim/kontact/plugins/CMakeLists.txt. Include the subdirectory hello like this:
 echo "add_subdirectory( weather )" >> kdepim/kontact/plugins/CMakeLists.txt
Then, recompile and install your kdepim 
 itchy:~/kdepim # make -j4 && make install
Call kontact and you should see an additional plugin.
 
== plugin <-> application Communication ==
 
Somehow, your kontact plugin must be able to communicate with your application. For example, if you have a mail application, there will be a need for a button "new mail" in kontact. If this button is clicked, the plugin needs to call a function in the mail application (for corba fans: "needs to send a message to the application"). This is done via dbus. The kontact plugin gets an auto-generated dbus interface provided with the following addition to CMakeLists.txt:
 qt4_add_dbus_interfaces(kontact_hello_PART_SRCS ${CMAKE_SOURCE_DIR}/hello/org.kde.hello.hello.xml)
The above example is about the "hello" application.
 
== Integration into kontact's settings ==
 
If you want your plugin to be configurable from within kontact (this is needed e.g. to deselect it), have a look into svn how other made this, e.g. [http://websvn.kde.org/?view=rev&revision=815080 here]
 
= Beyond hello world =
 
== An application around your kpart ==
 
To write an application that only contains your kpart, see [[Development/Tutorials/Using_KParts]].
 
== Context menu in the kontact plugin ==
TODO, e.g. [[user:Tstaerk]]
 
= 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
 
[[Category:PIM]]
[[Category:Tutorial]]

Difference between revisions of "Development/Tutorials/Writing kontact plugins"

Revision as of 20:38, 29 June 2011

Contents

Introduction

Writing a KPart

CMakeLists.txt

hello_part.h