Development/Tutorials/KDE2/KHello/Tutorial 2

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In this step I describe how a window class is created.

Source code

Now there are three files

 1 /************* khello.h *******************/
 2 #include <kapp.h>
 3 #include <kmainwindow.h>
 5 class KHello : public KMainWindow
 6 {
 8 public:
 9   void closeEvent(QCloseEvent *);
10 };
1 /************* ******************/
2 #include "khello.moc"
4 void KHello::closeEvent(QCloseEvent *e)
5 {
6   kapp->beep();
7   KMainWindow::closeEvent(e);
8 }
 1 /************* ********************/
 2 #include "khello.h"
 4 int main( int argc, char **argv )
 5 {
 6   KApplication a( argc, argv, "khello" );
 7   KHello *w = new KHello();
 8   w->setGeometry(100,100,200,100);
10   a.setMainWidget( w );
11   w->show();
12   return a.exec();
13 }

Explaining the code

There are a few commands that need explaining:


This is a command to the meta object compiler, which is included in the developer files for QT. You must start each KDE class with this line.

void closeEvent(QCloseEvent *);

This function is called when your window is being closed. We sound a beep when that happens and then call the original closeEvent() function. The original closeEvent() function takes care to exit the application when the last window gets closed.

#include "khello.moc"

The meta object compiler produces a moc file, which you must include. The moc file is an extended version of your header file.


[on linux where KDEDIR and QTDIR contain the paths to where KDE and Qt are installed respectively] [FreeBSD 5.x users may omit the -ldl]

g++ -c -I$KDEDIR/include -I$QTDIR/include -fno-rtti
moc khello.h -o khello.moc
g++ -c -I$KDEDIR/include -I$QTDIR/include -fno-rtti
g++ -L$KDEDIR/lib -L$QTDIR/lib -lkdeui -lkdecore -lqt -ldl -o khello main.o khello.o

[if moc is not in your path try $QTDIR/bin/moc]

This page was last modified on 29 June 2011, at 20:52. Content is available under Creative Commons License SA 3.0 as well as the GNU Free Documentation License 1.2 unless otherwise noted.