How to propagate keyPressEvent on different qt QMainWindow - events

Question

I have 2 different QMainWindow, the first is the parent of the second. I want press some keys in the children windows and propagate the event in the parent. I create for everyone the function void keyPressEvent(QKeyEvent* event); but when i press key on the children the event is not propagate to the parent. Why?
This is the code...
//Parent class.h
#ifndef MAINWINDOW_H
#define MAINWINDOW_H
#include <QMainWindow>
#include <QKeyEvent>
#include "test.h"
#include <QDebug>
namespace Ui {
class MainWindow;
}
class MainWindow : public QMainWindow
{
Q_OBJECT
public:
explicit MainWindow(QWidget *parent = 0);
~MainWindow();
protected:
void keyPressEvent(QKeyEvent* event);
private:
Ui::MainWindow *ui;
test *form;
private slots:
void on_pushButton_clicked();
};
#endif // MAINWINDOW_H
//Parent class.cpp
#include "mainwindow.h"
#include "ui_mainwindow.h"
MainWindow::MainWindow(QWidget *parent) : QMainWindow(parent),ui(new Ui::MainWindow)
{
ui->setupUi(this);
form = new test(this);
}
MainWindow::~MainWindow()
{
delete ui;
}
void MainWindow::keyPressEvent(QKeyEvent* event)
{
qDebug() << event->text();
}
void MainWindow::on_pushButton_clicked()
{
form->show();
}
//Children class.h
#ifndef TEST_H
#define TEST_H
#include <QMainWindow>
#include <QKeyEvent>
namespace Ui {
class test;
}
class test : public QMainWindow
{
Q_OBJECT
public:
explicit test(QWidget *parent = 0);
~test();
protected:
void keyPressEvent(QKeyEvent* event);
private:
Ui::test *ui;
};
#endif // TEST_H
//Children class.cpp
#include "test.h"
#include "ui_test.h"
test::test(QWidget *parent) : QMainWindow(parent), ui(new Ui::test)
{
ui->setupUi(this);
}
test::~test()
{
delete ui;
}
void test::keyPressEvent(QKeyEvent* event)
{
qDebug() << event->text();
event->ignore();
}

Answer 1

A QMainWindow is a top-level window and that is usually where event propagation ends. I'm not entirely clear what may be the rule though when a top-level window is parented. By your results, I'll have to assume that it stands.
In any case, you should be able to get the event by defining a filter method in your MainWindow class and installing it on test class. Refer to this documentation.
You also have the option of overriding the event() method of QApplication.