How to close all windows that were created in main()?

[Mister_Crac]

If you create more than one window inside of main(), how do destroy all of them when the main window is closed by the user? So he does not have to close all windows manually?

Code example:

#ifndef CLOSETEST_H
#define CLOSETEST_H
#include <QtGui>
 
class CloseTest : public QWidget {
 
public:
	CloseTest(QWidget *parent = 0);
};
 
#endif

#ifndef CLOSETEST_H
#define CLOSETEST_H
#include <QtGui>

class CloseTest : public QWidget {

public:
	CloseTest(QWidget *parent = 0);
};

#endif

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#include "CloseTest.h"
 
CloseTest::CloseTest(QWidget *parent)
{
	QHBoxLayout *layout = new QHBoxLayout;
	QLabel *label = new QLabel("This is a test");
 
	layout->addWidget(label);
	setLayout(layout);
}

#include "CloseTest.h"

CloseTest::CloseTest(QWidget *parent)
{
	QHBoxLayout *layout = new QHBoxLayout;
	QLabel *label = new QLabel("This is a test");

	layout->addWidget(label);
	setLayout(layout);
}

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#include <QApplication>
#include "CloseTest.h" 
 
int main(int argc, char *argv[])
{
	QApplication app(argc, argv);
 
	QLabel main("This is the main label");
	main.resize(300,150);
	main.show();
 
	CloseTest ct;
	ct.show();
 
	return app.exec();
}

#include <QApplication>
#include "CloseTest.h" 

int main(int argc, char *argv[])
{
	QApplication app(argc, argv);
	
	QLabel main("This is the main label");
	main.resize(300,150);
	main.show();

	CloseTest ct;
	ct.show();

	return app.exec();
}

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[Mister_Crac]

I tried this:

QObject::connect(&main, SIGNAL(destroyed()), &ct, SLOT(close()));

QObject::connect(&main, SIGNAL(destroyed()), &ct, SLOT(close()));

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but to no avail.

[jpn]

You have to set the Qt::WA_DeleteOnClose attribute to true so that the widget gets deleted upon close:

#include <QtGui>
 
int main(int argc, char *argv[])
{
	QApplication a(argc, argv);
 
	QLabel* label1 = new QLabel("a");
	label1->setAttribute(Qt::WA_DeleteOnClose, true);
	a.connect(label1, SIGNAL(destroyed()), &a, SLOT(quit()));
	label1->show();
 
	QLabel* label2 = new QLabel("b");
	label2->setAttribute(Qt::WA_DeleteOnClose, true);
	a.connect(label2, SIGNAL(destroyed()), &a, SLOT(quit()));
	label2->show();
 
	return a.exec();
}

#include <QtGui>

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

	QLabel* label1 = new QLabel("a");
	label1->setAttribute(Qt::WA_DeleteOnClose, true);
	a.connect(label1, SIGNAL(destroyed()), &a, SLOT(quit()));
	label1->show();

	QLabel* label2 = new QLabel("b");
	label2->setAttribute(Qt::WA_DeleteOnClose, true);
	a.connect(label2, SIGNAL(destroyed()), &a, SLOT(quit()));
	label2->show();

	return a.exec();
}

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EDIT: Btw, make sure you allocate widgets on stack if you set Qt::WA_DeleteOnClose attribute! Otherwise you'll get a crash due to double delete...

[Mister_Crac]

EDIT: Btw, make sure you allocate widgets on stack if you set Qt::WA_DeleteOnClose attribute! Otherwise you'll get a crash due to double delete...

On the stack? I thought this allocates an object on the heap:

Object *example = new Object;

Object *example = new Object;

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Anyways it works like you suggested, thank you!

[jpn]

On the stack? I thought this allocates an object on the heap:

Argh, sorry. I was in a hurry when answering. I meant heap while I still wrote stack..

[Matt Smith]

If you create more than one window inside of main(), how do destroy all of them when the main window is closed by the user? So he does not have to close all windows manually?

Try the static/slot function QApplication::closeAllWindows(). Documentation to be found here.

[Mister_Crac]

Try the static/slot function QApplication::closeAllWindows(). Documentation to be found here.

Hooray for another possibility!