[SOLVED] QDialog - overwriting the native "Expand" event

maximus

I would like to reimplement what the native "Expand" button does inside a QDialog
Instead of showing Maximized, I would show the dialog Fullscreen.

First, I have to catch the event to reimplement it, but not sure which one I have to reimplement
I tried :
@void resizeEvent(QResizeEvent *event);@

that comes from QWidget but this event throw all resize not just the "expand" event.

If you know a way to do it, would be nice to share, Thank you!

dheerendra

Can you check QEvent::WindowStateChange ?

maximus

This seems to work :

However I would like to catch the click on the button Expand before the Expand button cause the event, because now i'm a bit late and need to react to what just happened, I would like to overwrite the behavior of the Expand button, if that is ever possible.

@ void WorkoutDialog::changeEvent(QEvent *event) {

 qDebug() << "changeEvent-------------------" << event << "type" << event->type();

 if (event->type() == QEvent::WindowStateChange) {
     qDebug() << "WINDOW CHANGE";
 }

}@

dheerendra

You can try this.

@void Widget::changeEvent(QEvent *event)
{
if (event->type() == QEvent::WindowStateChange)
if(windowState().testFlag(Qt::WindowMaximized) == true)
qDebug() << "Maximize " << endl;
QWidget::changeEvent(event);
}@

dheerendra

You should use eventFilter to filter out the required events before passing or try re-implementing event() itself and handle appropriately.

bool Widget::event(QEvent *evt){
if (evt->type() == QEvent::WindowStateChange) {
qDebug() << "WIndow changed =" << evt->type() << endl;
if(windowState().testFlag(Qt::WindowMaximized) == true)
qDebug() << "Maximize. I'm handling it. " << endl;
return true;
}
return QWidget::event(evt);
}

maximus

With this:

@void WorkoutDialog::changeEvent(QEvent *event) {

if (event->type() == QEvent::WindowStateChange) {
    if(windowState().testFlag(Qt::WindowMaximized) == true) {
        qDebug() << "Maximize " << endl;
        return;   // Do not maximize, exit and cancel event
    }
}
else {
    QWidget::changeEvent(event);
}

}@

The Maximize button still works, I would like to disable it's original functionality and put a new one, possible? Thanks for the help!

[Edit: oh yes I completely forgot about EventFilter, will try this approach and post result]

maximus

It seems there is no way to cancel the original native event "expand"

With the code bellow, I can see when a Expand occur, but have no way to cancel it, right? I could call a fullscreen after the expand, but it seems bad, any other way? thank you!

@bool WorkoutDialog::eventFilter(QObject *watched, QEvent *event) {

 Q_UNUSED(watched);

qDebug() << "watched object" << watched << "event:" << event << "eventType" << event->type();


if(event->type() == QEvent::WindowStateChange)
{
    qDebug() << "WindowStateChange!!!!!!!!!!!!!!!!!!!!!!!!!!!****************";
    if(windowState().testFlag(Qt::WindowMaximized) == true) {
        qDebug() << "Maximize " << endl;
        this->showFullScreen();
        return true;
    }

}

return false;@

maximus

So far it works with this code :

constructor :

@ ui->setupUi(this);
Qt::WindowFlags flags = Qt::Window;
this->setWindowFlags(flags);

installEventFilter(this);@

eventFilter:

@bool WorkoutDialog::eventFilter(QObject *watched, QEvent *event) {

Q_UNUSED(watched);

qDebug() << "watched object" << watched << "event:" << event << "eventType" << event->type();


if(event->type() == QEvent::WindowStateChange)
{
    qDebug() << "WindowStateChange!!!!!!!!!!!!!!!!!!!!!!!!!!!****************";
    if(windowState().testFlag(Qt::WindowMaximized) == true) {
        qDebug() << "Maximize " << endl;
        this->showFullScreen();
        return true;
    }

}
return false;

}@