Delete memory to window handle from child on close in QT

Question

Let see my conf:

mainwindow.h
second_window.h

1. Keep pointer to second_window in class methods ( public: second_window * h_window; )
2. Class mainwindow opens second_window.

In second_window i catch eventClose(); And there i want to delete h_window; But i got a access error, i thought that window is still opened so when i try to delete pointer memory i got error.

Other idea when i should delete this pointer?

Answer 1

If both windows are independant and thus having no parents, then a way to solve is with QPointer and setAttribute(Qt::WA_DeleteOnClose).

class mainwindow : public QWidget {
  public:
    ~mainwindow() {
      delete h_window; // deletes h_window if it is not 0 (that is, not closed yet)
    }
    void showSecondWindow() {
      if ( ! h_window ) {
        h_window = new second_window();
      }
      h_window->show();
      h_window->activateWindow();
    }
  private:
    QPointer<second_window> h_window; // h_window will automatically become 0 when second_window is deleted.
}

class second_window : public QWidget {
  public:
    second_window() {
      setAttribute(Qt::WA_DeleteOnClose); // automatically delete itself when window is closed
    }
}