Difference between revisions of "Development/Tutorials/Programming Tutorial KDE 4/Using KConfig"

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==Moving On==
==Moving On==
For a better understanding of the XML used in KConfig XT you could try
[[Development/Tutorials/Programming_Tutorial_KDE_4/How_to_write_an_XML_parser|to write an Xml Parser]]

Revision as of 17:54, 27 June 2007



Author: Matt Williams

In this tutorial, we're going to be showing you how to utilise KConfig XT in an application. It is recommended that you read Development/Tutorials/Using KConfig XT before continuing in order to familiarise yourself with the framework.


KConfig XT

At first we make new File called tutorial4.kcfg within the source directory of your project.

<?xml version="1.0" encoding="UTF-8"?> <!DOCTYPE kcfg SYSTEM "http://www.kde.org/standards/kcfg/1.0/kcfg.xsd"> <kcfg> <kcfgfile name="kjotsrc"/> <include>kglobalsettings.h</include> <group name="kjots"> <entry name="showAction" type="Bool"> <label>Whether setupAction is called</label> <default>true</default> </entry> </group> </kcfg>

This code makes a setting of the type bool, which determines whether we want to do something. Then we set the default value to be true.

Always start the value of <entry name=""> in lower case since KConfig XT sets them to lower case within the generated headers either way. If you don't this could give you some nearly untraceable errors

Now we make a new File called tutorial4.kcfgc.

File=tutorial4.kcfg ClassName=tutorial4 Singleton=true Mutators=true

This should set up your configuration for now.

The Code


  1. ifndef MAINWINDOW_H
  2. define MAINWINDOW_H
  1. include <KXmlGuiWindow>
  2. include <KTextEdit>

class MainWindow : public KXmlGuiWindow {

public: MainWindow(QWidget *parent=0); private: KTextEdit* textArea; void setupActions(); void setupConfig(); void readConfig(); void saveSettings(); int m_showAction;


  1. endif

There are some new voids in here, as well as m_showAction witch determines the value stored in KConfig XT. Despite that value being a bool we can actually use an integer here, since the type is converted either way.


  1. include "mainwindow.h"
  2. include "tutorial4.h"
  1. include <KApplication>
  2. include <KAction>
  3. include <KLocale>
  4. include <KActionCollection>
  5. include <KStandardAction>
  6. include <KConfigDialog>

MainWindow::MainWindow(QWidget *parent) : KXmlGuiWindow(parent) {

textArea = new KTextEdit; setCentralWidget(textArea); setupConfig(); }

void MainWindow::setupActions() {

QAction* clearAction = actionCollection()->addAction( "clear" );

clearAction->setText(i18n("Clear")); clearAction->setIcon(KIcon("filenew")); clearAction->setShortcut(Qt::CTRL+ Qt::Key_W);

connect(clearAction, SIGNAL(triggered(bool)), textArea, SLOT(clear()));

KStandardAction::quit(kapp, SLOT(quit()), actionCollection());



void MainWindow::setupConfig() { readConfig();


void MainWindow::readConfig() { m_showAction = tutorial4::showAction(); if(m_showAction = (true)) setupActions();


void MainWindow::saveSettings() { tutorial4::setShowAction(m_showAction); tutorial4::self()->writeConfig(); }

At first we import "tutorial4.h", which should be auto-generated at runtime by KConfig XT every time you compile this. MainWindow and SetupActions are copied from the tutorials before. The only thing new is that we now call a new void called setupConfig. This then calls readConfig. We could also call saveSettings(but only after we called readConfig), but since we don't change any values there this is more of a "proof of concept".

Within readConfig we assign m_showAction the value of the setting showAction. If this returns true setupsActions makes buttons and all that. When false it doesn't.

The setShowActions() in saveSettings() overwrites showAction with a value of your choice, in this case with itself. Then you need to call writeConfig() to apply the changes you made.


  1. include "mainwindow.h"

  1. include <KApplication>
  2. include <KAboutData>
  3. include <KCmdLineArgs>

int main (int argc, char *argv[]) { KAboutData aboutData( "tutorial4", "tutorial4", "0.4", "KMessageBox popup", KAboutData::License_GPL, "(c) 2007" ); KCmdLineArgs::init( argc, argv, &aboutData );

KApplication app;

MainWindow* window = new MainWindow(); window->show();

return app.exec();


No news in here


<?xml version="1.0" encoding="UTF-8"?> <!DOCTYPE kpartgui SYSTEM "kpartgui.dtd"> <gui name="tutorial4" version="1">

 <ToolBar name="mainToolBar" >
   <text>Main Toolbar</text>
   <Action name="clear" />
   <Menu name="file" >
     <Action name="clear" />









KDE4_ADD_KCFG_FILES(tutorial4_SRCS settings.kcfgc)

KDE4_ADD_EXECUTABLE(tutorial4 ${tutorial4_SRCS})


install( TARGETS tutorial4 DESTINATION ${BIN_INSTALL_DIR}) install( FILES tutorial4ui.rc DESTINATION ${DATA_INSTALL_DIR}/tutorial4) install( FILES tutorial4.kcfg DESTINATION ${KCFG_INSTALL_DIR} )

Moving On

For a better understanding of the XML used in KConfig XT you could try to write an Xml Parser

This page was last edited on 27 June 2007, at 17:54. Content is available under Creative Commons License SA 4.0 unless otherwise noted.