toggled(bool) signal does not call my slot?

[Asperamanca]

Hi,

I have a toggle action that should call a function within my class when toggled.
However, it does not, and I have no idea why not.

Could someone please take a look?

In my widget constructor:

...
QAction *topmostAction = new QAction("Stay on &Top", this);
topmostAction->setShortcut(QKeySequence("Ctrl+T"));
topmostAction->setCheckable(true);
topmostAction->setChecked(false);
connect(topmostAction, SIGNAL(toggled(bool)),
        this, SLOT(setTopmost(bool)));
 
addAction(topmostAction);
...

...
QAction *topmostAction = new QAction("Stay on &Top", this);
topmostAction->setShortcut(QKeySequence("Ctrl+T"));
topmostAction->setCheckable(true);
topmostAction->setChecked(false);
connect(topmostAction, SIGNAL(toggled(bool)),
        this, SLOT(setTopmost(bool)));

addAction(topmostAction);
...

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and later on the function that should be called:

void OvenTimerWidget::setTopmost(bool bTopmost)
{
    Qt::WindowFlags flags;
 
    flags = windowFlags();
 
    if (bTopmost)
        flags |= Qt::WindowStaysOnTopHint;
    else
        flags &= (!Qt::WindowStaysOnTopHint);
 
    setWindowFlags(flags);
 
    emit topmostChanged(bTopmost);
}

void OvenTimerWidget::setTopmost(bool bTopmost)
{
    Qt::WindowFlags flags;

    flags = windowFlags();

    if (bTopmost)
        flags |= Qt::WindowStaysOnTopHint;
    else
        flags &= (!Qt::WindowStaysOnTopHint);

    setWindowFlags(flags);

    emit topmostChanged(bTopmost);
}

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I have my breakpoint in there, click on the (context) menu entry, it gets checked, but I never reach the breakpoint. What could be wrong here?

Thanks!

[Lykurg]

is setTopmost() defined as a slot and did you use the Q_OBJECT macro? Please show us your header file.

[aamer4yu]

Also is flags &= (!Qt::WindowStaysOnTopHint); correct ?
shouldnt it be
flags &= (^Qt::WindowStaysOnTopHint);

[Lykurg]

Also is flags &= (!Qt::WindowStaysOnTopHint); correct ?
shouldnt it be
flags &= (^Qt::WindowStaysOnTopHint);

Ehm, no It should be

flags &= ~Qt::WindowStaysOnTopHint;

flags &= ~Qt::WindowStaysOnTopHint;

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But better just toogle the hint then you don't need the if/else:

flags ^= Qt::WindowStaysOnTopHint;

flags ^= Qt::WindowStaysOnTopHint;

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[aamer4yu]

flags &= ~Qt::WindowStaysOnTopHint

Ohh yeah

I mean negate only.. guess my mind swapped symbols for negate and xor

[Asperamanca]

Sure enough, I forgot to declare that function a slot. Thanks!

Now I just have to find out why actually calling that slot kills my application. Can something like setting window flags not be done from within the context of a context menu of that window?

I have boiled it down to a very simple sample program. When you run it, open the context menu and select "Stay on Top", the window disappears (even from the taskbar), and I have to kill the application using the task manager or debugger.

Why?

Header file "testtopmostwindow.h"

#ifndef TESTWINDOWTOPMOST_H
#define TESTWINDOWTOPMOST_H
 
#include <QWidget>
 
 
class TestWindowTopmost : public QWidget
{
    Q_OBJECT
 
public:
    TestWindowTopmost(QWidget *parent = 0);
 
public slots:
    void setTopmost(bool);
};
 
#endif // TESTWINDOWTOPMOST_H

#ifndef TESTWINDOWTOPMOST_H
#define TESTWINDOWTOPMOST_H

#include <QWidget>


class TestWindowTopmost : public QWidget
{
    Q_OBJECT

public:
    TestWindowTopmost(QWidget *parent = 0);

public slots:
    void setTopmost(bool);
};

#endif // TESTWINDOWTOPMOST_H

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Source file "testtopmostwindow.cpp":

#include "testwindowtopmost.h"
#include <QAction>
 
TestWindowTopmost::TestWindowTopmost(QWidget *parent) : QWidget(parent)
{
   QAction *topmostAction = new QAction("Stay on &Top", this);
   topmostAction->setShortcut(QKeySequence("Ctrl+T"));
   topmostAction->setCheckable(true);
   topmostAction->setChecked(false);
   connect(topmostAction, SIGNAL(toggled(bool)),
           this, SLOT(setTopmost(bool)));
   addAction(topmostAction);
 
   setContextMenuPolicy(Qt::ActionsContextMenu);
   setWindowTitle(tr("Test window topmost"));
}
 
void TestWindowTopmost::setTopmost(bool bTopmost)
{
   // For now, just attempt to set a sensible base flag, like in the windowflags example
   setWindowFlags(Qt::Dialog);
}

#include "testwindowtopmost.h"
#include <QAction>

TestWindowTopmost::TestWindowTopmost(QWidget *parent) : QWidget(parent)
{
   QAction *topmostAction = new QAction("Stay on &Top", this);
   topmostAction->setShortcut(QKeySequence("Ctrl+T"));
   topmostAction->setCheckable(true);
   topmostAction->setChecked(false);
   connect(topmostAction, SIGNAL(toggled(bool)),
           this, SLOT(setTopmost(bool)));
   addAction(topmostAction);

   setContextMenuPolicy(Qt::ActionsContextMenu);
   setWindowTitle(tr("Test window topmost"));
}

void TestWindowTopmost::setTopmost(bool bTopmost)
{
   // For now, just attempt to set a sensible base flag, like in the windowflags example
   setWindowFlags(Qt::Dialog);
}

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"main.cpp":

#include <QtGui/QApplication>
#include "testwindowtopmost.h"
 
 
int main(int argc, char *argv[])
{
    QApplication a(argc, argv);
    TestWindowTopmost w;
 
    w.resize(200,200);
    w.show();
    return a.exec();
}

#include <QtGui/QApplication>
#include "testwindowtopmost.h"


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

    w.resize(200,200);
    w.show();
    return a.exec();
}

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Any ideas?

[Asperamanca]

Found my mistake: Forgot the show() after setting the flags.