C-Programmierung
Qt Spezialisierung
← Compilation eines Qt Projekts mit CMake | ● | Qt App Menu →
Now we create an application that will simply open a plain window containing a single widget, that is a QWidget without any functionality yet.
We run the application by returning execution control to its event loop:
#include <QtGui/QApplication>
#include <QtGui/QWidget>
int main(int argc, char *argv[])
{
QApplication app(argc, argv);
QWidget main;
main.show();
return(app.exec());
}
#include <QtGui/QWidget>
int main(int argc, char *argv[])
{
QApplication app(argc, argv);
QWidget main;
main.show();
return(app.exec());
}
Then we derive from QWidget to specialize its paintEvent() method:
#include <QWidget>
#include <QPainter>
class MyQPainterWidget: public QWidget
{
public:
//! default ctor
MyQPainterWidget(QWidget *parent = 0)
: QWidget(parent)
{}
//! dtor
~MyQPainterWidget()
{}
protected:
//! reimplemented paint event method
void paintEvent(QPaintEvent *)
{
QPainter painter(this);
painter.setPen(Qt::green);
painter.setFont(QFont("Arial", 100));
painter.drawText(rect(), Qt::AlignCenter, "Qt");
}
};
#include <QPainter>
class MyQPainterWidget: public QWidget
{
public:
//! default ctor
MyQPainterWidget(QWidget *parent = 0)
: QWidget(parent)
{}
//! dtor
~MyQPainterWidget()
{}
protected:
//! reimplemented paint event method
void paintEvent(QPaintEvent *)
{
QPainter painter(this);
painter.setPen(Qt::green);
painter.setFont(QFont("Arial", 100));
painter.drawText(rect(), Qt::AlignCenter, "Qt");
}
};
The reimplemented paintEvent method draws a centered text by using the QPainter class.
Now we replace the main application widget with our customized widget:
#include "MyQPainterWidget.h"
MyQPainterWidget main;
main.show();
MyQPainterWidget main;
main.show();
← Compilation eines Qt Projekts mit CMake | ● | Qt App Menu →