Development/Tutorials/Using KParts: Difference between revisions

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    {{Template:I18n/Language Navigation Bar|Development/Tutorials/Using_KParts}}
     


    {{TutorialBrowser|
    {{TutorialBrowser|
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    This tutorial will show you how to use a KPart in your application, and how to create your own KPart.
    This tutorial will show you how to use a KPart in your application, and how to create your own KPart.
    KParts consist of a .desktop file describing the KPart and a .so file containing the function names and code. The .desktop file resides in KDE's services directory, you can find it out like this:
    # kde4-config --path services
    /root/.kde/share/kde4/services/:/usr/local/share/kde4/services/
    The first kPart we describe is KatePart, an editor representing a typical [http://api.kde.org/4.0-api/kdelibs-apidocs/kparts/html/classKParts_1_1ReadWritePart.html ReadWritePart]. A typical [http://api.kde.org/4.0-api/kdelibs-apidocs/kparts/html/classKParts_1_1ReadOnlyPart.html ReadOnlyPart] would be [http://api.kde.org/4.5-api/kdebase-apps-apidocs/konsole/html/classKonsole_1_1Part.html konsolePart].


    == Using Katepart ==
    == Using Katepart ==
    Line 27: Line 33:
    === main.cpp ===
    === main.cpp ===


    <code cppqt>
    <syntaxhighlight lang="cpp-qt">
    #include <KApplication>
    #include <KApplication>
    #include <KAboutData>
    #include <KAboutData>
    Line 37: Line 43:
    int main (int argc, char *argv[])
    int main (int argc, char *argv[])
    {
    {
         KAboutData aboutData( "kparttutorial1", "kparttutorial1",
         KAboutData aboutData( "kparttut1", "kparttut1",
             ki18n("KPart Tutorial 1"), "0.1",
             ki18n("KPart Tutorial 1"), "0.1",
             ki18n("A MainWindow for a KatePart."),
             ki18n("A MainWindow for a KatePart."),
    Line 62: Line 68:
    }
    }


    </code>
    </syntaxhighlight>


    The main.cpp file is the same as that used in [[Development/Tutorials/KCmdLineArgs|Tutorial 5 - Command line arguments]].The only difference is in the details of the KAboutData.
    The main.cpp file is the same as that used in [[Development/Tutorials/KCmdLineArgs|Tutorial 5 - Command line arguments]].The only difference is in the details of the KAboutData.
    Line 68: Line 74:
    === mainwindow.h ===
    === mainwindow.h ===


    <code cppqt>
    <syntaxhighlight lang="cpp-qt">
     
    #ifndef KPARTTUTORIAL1_H
    #define KPARTTUTORIAL1_H


    #include <kparts/mainwindow.h>
    #ifndef KPARTTUTORIAL1_H       
     
    #define KPARTTUTORIAL1_H       
    /**
                                   
    #include <kparts/mainwindow.h>
                                   
    /**                            
      * This is the application "Shell".  It has a menubar, toolbar, and
      * This is the application "Shell".  It has a menubar, toolbar, and
      * statusbar but relies on the "Part" to do all the real work.
      * statusbar but relies on the "Part" to do all the real work.    
      *
      *                                                                
      * @short Application Shell
      * @short Application Shell                                      
      * @author Developer <[email protected]>
      * @author Developer <[email protected]>                          
      * @version 0.1
      * @version 0.1
      */
      */
    Line 97: Line 103:
         virtual ~MainWindow();
         virtual ~MainWindow();


    public slots:
         /**
         /**
         * Use this method to load whatever file/URL you have
         * Use this method to load whatever file/URL you have
         */
         */
         void load(const KUrl& url);
         void load(const KUrl& url);
        /**
        * Use this method to display an openUrl dialog and
        * load the URL that gets entered
        */
        void load();


    private:
    private:
    Line 111: Line 124:
    #endif // KPARTTUT1_H
    #endif // KPARTTUT1_H


    </code>
    </syntaxhighlight>


    The mainwindow.h file is very simple. The important thing to notice here is that the MainWindow class inherits from KParts::MainWindow.
    The mainwindow.h file is very simple. The important thing to notice here is that the MainWindow class inherits from KParts::MainWindow.
    Line 117: Line 130:
    === mainwindow.cpp ===
    === mainwindow.cpp ===


    <code cppqt>
    <syntaxhighlight lang="cpp-qt">


    #include "mainwindow.h"
    #include "mainwindow.h"
    Line 129: Line 142:
    #include <klibloader.h>
    #include <klibloader.h>
    #include <kmessagebox.h>
    #include <kmessagebox.h>
    #include <kservice.h>
    #include <kstandardaction.h>
    #include <kstandardaction.h>
    #include <kstatusbar.h>
    #include <kstatusbar.h>
    Line 142: Line 156:
         setupActions();
         setupActions();


         // this routine will find and load our Part
         //query the .desktop file to load the requested Part
         KLibFactory *factory = KLibLoader::self()->factory("katepart");
         KService::Ptr service = KService::serviceByDesktopPath
         if (factory)
                              ("katepart");
     
         if (service)
         {
         {
            // now that the Part is loaded, we cast it to a Part to get
          m_part = service->createInstance<KParts::ReadWritePart>(0);
            // our hands on it
            m_part = static_cast<KParts::ReadWritePart *>
                    (factory->create(this, "KatePart" ));


            if (m_part)
          if (m_part)
            {
          {
                 // tell the KParts::MainWindow that this is indeed
                 // tell the KParts::MainWindow that this is indeed
                 // the main widget
                 // the main widget
    Line 161: Line 174:
                 // and integrate the part's GUI with the shell's
                 // and integrate the part's GUI with the shell's
                 createGUI(m_part);
                 createGUI(m_part);
            }
          }
          else
          {
              return;//return 1;
          }
         }
         }
         else
         else
    Line 167: Line 184:
             // if we couldn't find our Part, we exit since the Shell by
             // if we couldn't find our Part, we exit since the Shell by
             // itself can't do anything useful
             // itself can't do anything useful
             KMessageBox::error(this, "Could not find our Part!");
             KMessageBox::error(this, "service katepart not found");
             qApp->quit();
             qApp->quit();
             // we return here, cause qApp->quit() only means "exit the
             // we return here, cause qApp->quit() only means "exit the
    Line 186: Line 203:
    void MainWindow::setupActions()
    void MainWindow::setupActions()
    {
    {
         KStandardAction::open(this, SLOT(fileOpen()),  
         KStandardAction::open(this, SLOT(load()),  
             actionCollection());
             actionCollection());
         KStandardAction::quit(qApp, SLOT(closeAllWindows()),
         KStandardAction::quit(qApp, SLOT(closeAllWindows()),
    Line 197: Line 214:
    }
    }


    </code>
    </syntaxhighlight>


    The mainwindow.cpp file contains the implementation of MainWindow. The constructor of this class contains all the code used to load the KPart.
    The mainwindow.cpp file contains the implementation of MainWindow. The constructor of this class contains all the code used to load the KPart.


    First it sets up the actions used by the main window (Open and Quit), and then sets up the gui elements to go with these items (toolbar items, menu items, keyboard shortcuts). Next is the standard code used to load the KPart. The createGUI method is responsible for merging the toolbars and menus of the KPart with the rest of the application.
    First it sets up the actions used by the main window (Open and Quit), and then sets up the gui elements to go with these items (toolbar items, menu items, keyboard shortcuts). Next is the standard code used to load the KPart. The createGUI method is responsible for merging the toolbars and menus of the KPart with the rest of the application.
    Note: although the part can also be loaded using KPluginLoader, this method is depricated.
        KPluginFactory* factory = KPluginLoader("katepart").factory();


    === kparttut1ui.rc ===
    === kparttut1ui.rc ===


    <code xml>
    <syntaxhighlight lang="xml">
    <!DOCTYPE kpartgui SYSTEM "kpartgui.dtd">
    <!DOCTYPE kpartgui SYSTEM "kpartgui.dtd">
    <kpartgui name="kparttut1" version="1">
    <kpartgui name="kparttut1" version="1">
    Line 224: Line 245:
    </ToolBar>
    </ToolBar>
    </kpartgui>
    </kpartgui>
    </code>
    </syntaxhighlight>


    The kparttut1ui.rc file is used to define how the actions in the part and the actions in the main window will be merged together. The <tt><Merge /></tt> element in the file menu for example indicates that any part containing actions in a file menu should list its parts after the file_open action and before the file_quit action.
    The kparttut1ui.rc file is used to define how the actions in the part and the actions in the main window will be merged together. The <tt><Merge /></tt> element in the file menu for example indicates that any part containing actions in a file menu should list its parts after the file_open action and before the file_quit action.
    Line 230: Line 251:
    === CMakeLists.txt ===
    === CMakeLists.txt ===


    <code ini>
    <syntaxhighlight lang="cmake">


    project(kparttut1)
    project(kparttut1)
    Line 250: Line 271:
    install( FILES kparttut1ui.rc  
    install( FILES kparttut1ui.rc  
         DESTINATION  ${DATA_INSTALL_DIR}/kparttut1 )
         DESTINATION  ${DATA_INSTALL_DIR}/kparttut1 )
    </code>
    </syntaxhighlight>
    The CMakeLists.txt file is very simple in this case.
    The CMakeLists.txt file is very simple in this case.


    Line 256: Line 277:


    After compiling, linking and installing the application with
    After compiling, linking and installing the application with
      cmake . && make -j4 && make install
      mkdir build && cd build && cmake .. && make -j4 && make install
    it can be executed with  
    it can be executed with  
      kparttut1 filename
      kparttut1 ''filename''
    where filename is a text file to load. One of the source files would be a good example.
    where ''filename'' is a text file to load. One of the source files would be a good example.


    When the file loads you will have a full-featured kate editor running in its own window. All of the editor features of kate are available in the toolbars and menu.
    When the file loads you will have a full-featured kate editor running in its own window. All of the editor features of kate are available in the toolbars and menu.

    Revision as of 22:29, 14 July 2013


    How To Use KParts
    Tutorial Series   Plugins and KParts
    Previous   Tutorial 5 - Command line arguments
    What's Next   n/a
    Further Reading   KParts Documentation

    Introduction

    KPart technology is used in kde to reuse GUI components. The advantage that a KPart presents is that it comes with predefined toolbar actions. By using kparts in applications developers can spend less time implementing text editor or command line features, for example and just use a katepart or a konsolepart instead. KParts are also used with Plugin technology to embed applications inside another, such as integrating PIM applications into Kontact.

    This tutorial will show you how to use a KPart in your application, and how to create your own KPart.

    KParts consist of a .desktop file describing the KPart and a .so file containing the function names and code. The .desktop file resides in KDE's services directory, you can find it out like this:

    # kde4-config --path services
    /root/.kde/share/kde4/services/:/usr/local/share/kde4/services/
    

    The first kPart we describe is KatePart, an editor representing a typical ReadWritePart. A typical ReadOnlyPart would be konsolePart.

    Using Katepart

    Simple KDE applications use a MainWindow derived from KMainWindow (such as in previous tutorials). To use a KPart in an application, the MainWindow must instead be derived from KParts::MainWindow. This will then take care of integrating the toolbar and menu items of the kpart together.

    The following code creates a KParts::MainWindow with a kpart inside it.

    main.cpp

    #include <KApplication>
    #include <KAboutData>
    #include <KCmdLineArgs>
    #include <KUrl>
     
    #include "mainwindow.h"
     
    int main (int argc, char *argv[])
    {
        KAboutData aboutData( "kparttut1", "kparttut1",
            ki18n("KPart Tutorial 1"), "0.1",
            ki18n("A MainWindow for a KatePart."),
            KAboutData::License_GPL,
            ki18n("Copyright (c) 2007 Developer") );
        KCmdLineArgs::init( argc, argv, &aboutData );
     
        KCmdLineOptions options;
        options.add("+[file]", ki18n("Document to open"));
        KCmdLineArgs::addCmdLineOptions(options);
     
        KApplication app;
     
        MainWindow* window = new MainWindow();
        window->show();
    
        KCmdLineArgs *args = KCmdLineArgs::parsedArgs();
        if(args->count())
        {
            window->load(args->url(0).url());
        }
    
        return app.exec();
    }
    

    The main.cpp file is the same as that used in Tutorial 5 - Command line arguments.The only difference is in the details of the KAboutData.

    mainwindow.h

    #ifndef KPARTTUTORIAL1_H        
    #define KPARTTUTORIAL1_H        
                                    
    #include <kparts/mainwindow.h>  
                                    
    /**                             
     * This is the application "Shell".  It has a menubar, toolbar, and
     * statusbar but relies on the "Part" to do all the real work.     
     *                                                                 
     * @short Application Shell                                        
     * @author Developer <[email protected]>                           
     * @version 0.1
     */
    class MainWindow : public KParts::MainWindow
    {
        Q_OBJECT
    public:
        /**
         * Default Constructor
         */
        MainWindow();
    
        /**
         * Default Destructor
         */
        virtual ~MainWindow();
    
    public slots:
        /**
         * Use this method to load whatever file/URL you have
         */
        void load(const KUrl& url);
    
        /**
         * Use this method to display an openUrl dialog and
         * load the URL that gets entered
         */
        void load();
    
    private:
        void setupActions();
    
    private:
        KParts::ReadWritePart *m_part;
    };
    
    #endif // KPARTTUT1_H
    

    The mainwindow.h file is very simple. The important thing to notice here is that the MainWindow class inherits from KParts::MainWindow.

    mainwindow.cpp

    #include "mainwindow.h"
    
    #include <kaction.h>
    #include <kactioncollection.h>
    #include <kconfig.h>
    #include <kedittoolbar.h>
    #include <kfiledialog.h>
    #include <kshortcutsdialog.h>
    #include <klibloader.h>
    #include <kmessagebox.h>
    #include <kservice.h>
    #include <kstandardaction.h>
    #include <kstatusbar.h>
    #include <kurl.h>
    
    #include <QApplication>
    
    MainWindow::MainWindow()
        : KParts::MainWindow( )
    {
    
        // Setup our actions
        setupActions();
    
        //query the .desktop file to load the requested Part
        KService::Ptr service = KService::serviceByDesktopPath
                               ("katepart");
    
        if (service)
        {
          m_part = service->createInstance<KParts::ReadWritePart>(0);
    
          if (m_part)
          {
                // tell the KParts::MainWindow that this is indeed
                // the main widget
                setCentralWidget(m_part->widget());
    
                setupGUI(ToolBar | Keys | StatusBar | Save);
    
                // and integrate the part's GUI with the shell's
                createGUI(m_part);
          }
          else
          {
              return;//return 1; 
          }
        }
        else
        {
            // if we couldn't find our Part, we exit since the Shell by
            // itself can't do anything useful
            KMessageBox::error(this, "service katepart not found");
            qApp->quit();
            // we return here, cause qApp->quit() only means "exit the
            // next time we enter the event loop...
            return;
        }
    }
    
    MainWindow::~MainWindow()
    {
    }
    
    void MainWindow::load(const KUrl& url)
    {
        m_part->openUrl( url );
    }
    
    void MainWindow::setupActions()
    {
        KStandardAction::open(this, SLOT(load()), 
            actionCollection());
        KStandardAction::quit(qApp, SLOT(closeAllWindows()),
            actionCollection());
    }
    
    void MainWindow::load()
    {
        load(KFileDialog::getOpenUrl());
    }
    

    The mainwindow.cpp file contains the implementation of MainWindow. The constructor of this class contains all the code used to load the KPart.

    First it sets up the actions used by the main window (Open and Quit), and then sets up the gui elements to go with these items (toolbar items, menu items, keyboard shortcuts). Next is the standard code used to load the KPart. The createGUI method is responsible for merging the toolbars and menus of the KPart with the rest of the application.

    Note: although the part can also be loaded using KPluginLoader, this method is depricated.

       KPluginFactory* factory = KPluginLoader("katepart").factory();
    

    kparttut1ui.rc

    <!DOCTYPE kpartgui SYSTEM "kpartgui.dtd">
    <kpartgui name="kparttut1" version="1">
    <MenuBar>
      <Menu noMerge="1" name="file"><text>&amp;File</text>
        <Action name="file_open"/>
        <Separator/>
        <Merge/>
        <Separator/>
        <Action name="file_quit"/>
      </Menu>
    
      <Merge />
    </MenuBar>
    <ToolBar noMerge="1" name="mainToolBar"><text>Main Toolbar</text>
      <Action name="file_open"/>
      <Merge/>
    </ToolBar>
    </kpartgui>
    

    The kparttut1ui.rc file is used to define how the actions in the part and the actions in the main window will be merged together. The <Merge /> element in the file menu for example indicates that any part containing actions in a file menu should list its parts after the file_open action and before the file_quit action.

    CMakeLists.txt

    project(kparttut1)
    
    FIND_PACKAGE(KDE4 REQUIRED)
    INCLUDE_DIRECTORIES( ${KDE4_INCLUDES} . )
    
    set(kparttut1_SRCS
       main.cpp
       mainwindow.cpp
     )
    
    kde4_add_executable(kparttut1 ${kparttut1_SRCS})
    
    target_link_libraries(kparttut1 ${KDE4_KDEUI_LIBS} ${KDE4_KPARTS_LIBS})
    
    ########### install files ###############
    install(TARGETS kparttut1 DESTINATION ${BIN_INSTALL_DIR} )
    install( FILES kparttut1ui.rc 
        DESTINATION  ${DATA_INSTALL_DIR}/kparttut1 )
    

    The CMakeLists.txt file is very simple in this case.

    Running the Application

    After compiling, linking and installing the application with

    mkdir build && cd build && cmake .. && make -j4 && make install
    

    it can be executed with

    kparttut1 filename
    

    where filename is a text file to load. One of the source files would be a good example.

    When the file loads you will have a full-featured kate editor running in its own window. All of the editor features of kate are available in the toolbars and menu.

    You will notice that the 'Open' action you defined in the MainWindow class has also appeared in the toolbar and in the menu along with the 'Quit' action.

    The next tutorial will deal with creating your own kparts for use (and reuse) in other applications.