Modal dialog for confirming the user to close the window in Qt

README.md

Confirm dialog in Qt

Compiling

Run the following commands from the project dir:

$ qmake -project && qmake && make

main.cpp

#include <QApplication>
#include "widget.cpp"

int main(int argc, char *argv[])
{
	QApplication app(argc, argv);

	Widget widget;
	widget.show();

	return app.exec();
}

widget.cpp

#include "widget.h"

Widget::Widget(QWidget *parent) : QWidget(parent)
{
	label = new QLabel(tr("Try to close this window"), this);

	setWindowTitle(tr("Filename: README.txt [*]"));
	setWindowModified(true);
}

void Widget::closeEvent(QCloseEvent *event)
{
	if (Widget::closeWindow())
		event->accept();
	else
		event->ignore();
}

bool Widget::closeWindow()
{
	if (!isWindowModified())
		return true;

	QMessageBox::StandardButton answer = QMessageBox::question(
		this, 
		tr("Close the Window"),
		tr("Do you want to close the window?"),
		QMessageBox::Yes | QMessageBox::No
	);

	return answer == QMessageBox::Yes;
}

widget.h

#ifndef WIDGET_H
#define WIDGET_H

#include <QtGui>

class Widget : public QWidget
{
	Q_OBJECT

public:
	Widget(QWidget *parent = 0);

protected:
	void closeEvent(QCloseEvent *event);

private:
	bool closeWindow();
	QLabel *label;
};

#endif