Qt - How to get real size of maximized window that I have pointer to? - qt

Question

I have a method that get pointer to widget where should be setted some other widgets. I have to resize the main window, where that widget is placed and then I should get the real size of that widget.
I’ve tried to do this like:
void MyClass::setWidgets(QList<QWidget*> list, QWidget *parentWidget)
{
QWidget* mainWindow = parentWidget->window();
mainWindow->showMaximized();
int width = parentWidget->size().width();
int height = parentWidget->size().height();
/*... rest of method...*/
}
That method is call from other class.
But I read that I should wait for resizeEvent. Could anyone explain me how I should do this or if there is any option to get that size differently?

Answer 1

If you want to get events for a different object, you can install an event filter using QObject::installEventFilter.
A simple example for ResizeEvent is:
filter.hpp
#ifndef FILTER_HPP
#define FILTER_HPP
#include <QtGui>
class ResizeFilter : public QObject
{
Q_OBJECT
public:
ResizeFilter();
protected:
bool eventFilter(QObject *obj, QEvent *event);
};
#endif
filter.cpp
#include "filter.hpp"
ResizeFilter::ResizeFilter() : QObject() {}
bool ResizeFilter::eventFilter(QObject *obj, QEvent *event)
{
if (event->type() == QEvent::Resize)
{
QResizeEvent* resizeEv = static_cast<QResizeEvent*>(event);
qDebug() << resizeEv->size();
}
return QObject::eventFilter(obj, event);
}
main.cpp
#include <QtGui>
#include "filter.hpp"
int main(int argc, char** argv)
{
QApplication app(argc, argv);
ResizeFilter filter;
QWidget window;
window.installEventFilter(&filter);
window.showMaximized();
return app.exec();
}
filter.pro
TEMPLATE = app
HEADERS = filter.hpp
SOURCES = main.cpp filter.cpp
When testing this on my PC it gave the output:
QSize(840, 420)
QSize(1280, 952)