Archive:Development/Tutorials/Using KParts (zh CN)

Development/Tutorials/Using_KParts

如何使用KParts

Tutorial Series	插件和KParts
Previous	教程五 -命令行参数
What's Next	n/a
Further Reading	KParts文档

介绍

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.

使用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( "kparttutorial1", "kparttutorial1",
       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();

   /**
    * 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 <kstandardaction.h>
include <kstatusbar.h>
include <kurl.h>

include <QApplication>

MainWindow::MainWindow()

   : KParts::MainWindow( )

   // Setup our actions
   setupActions();

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

       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
   {
       // if we couldn't find our Part, we exit since the Shell by
       // itself can't do anything useful
       KMessageBox::error(this, "Could not find our Part!");
       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(fileOpen()), 
       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.

kparttut1ui.rc

<!DOCTYPE kpartgui SYSTEM "kpartgui.dtd"> <kpartgui name="kparttut1" version="1"> <MenuBar>

 <Menu noMerge="1" name="file"><text>&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>

kparttut1ui.rc文件用来定义Part中的动作（Action）如何于主窗口的动作（Action）合并起来。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 )

这里，CMakeLists.txt文件很简单。

运行

编译后，用下列方式连接，安装：

cmake . && make -j4 && make install

可以这样执行：

kparttut1 filename

文件名filename就是要加在的文本文件。源代码文件也可以。

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.

下一个教程会讲述如何在应用程序里使用，重用你创建的KPart。