how to run myfunction() when I close a window

[blackout69]

Hi everyone,
I need to run myfunction() when I close the window named mywindow programmatically opened inside the FullScreen class

.h
namespace Ui {
  class FullScreen;
}

class FullScreen : public QWidget
{
  Q_OBJECT

public:
  explicit FullScreen(QWidget *parent = nullptr);
  ~FullScreen();

private:
  Ui::FullScreen *ui;
  QWindow *mywindow;

private slots:
  void on_button_released();
  void myfunction();
};

.cpp

void FullScreen::on_button_released()
{
   WId wid = (WId)FindWindow(L"ScreenClass", nullptr);
   mywindow = QWindow::fromWinId(wid);

// I tried like this, but it doesn't work   
QObject::connect(mywindow, &QWindow::windowStateChanged, this, [this](Qt::WindowState state){
       if (state == Qt::WindowNoState && mywindow->isVisible() == false) {
           myfunction();
       }
   });
}

void FullScreen::myfunction()
{
  my code;
}

Does anyone have a different solution?
Thank you in advance
blackout69

[JonB]

@blackout69
To run code on closing a QWidget, either subclass and override closeEvent() or detect it via installEventFilter() (avoids subclassing, but here you are already subclassing).

[Bonnie]

@JonB Since the OP's window is got by QWindow::fromWinId (probably from a non-Qt program's window handle), I doubt he could get any information according to the doc of the function:

Note: The resulting QWindow should not be used to manipulate the underlying native window (besides re-parenting), or to observe state changes of the native window. Any support for these kind of operations is incidental, highly platform dependent and untested.

[JonB]

@Bonnie
Yes, I did not notice that was what the OP was asking about. Assuming that nothing like closeEvent() or installEventFilter() works I assume they need either to use purely non-Qt native code or perhaps Qt's nativeEventFilter()?