[Qt-interest] little help with layouts

[Luca Ferrari]

Hi,
moving my first steps in QT I got a behaviour I cannot understand. The window 
should display two labels and a few buttons, with different layouts, but I'm 
not getting what is wrong with the following code (that shows nothing):


MainWindow::MainWindow(QWidget *parent)
    : QMainWindow(parent)
{

    QHBoxLayout* mainLayout = new QHBoxLayout();
    this->setLayout( mainLayout );

    // a container for labels
    QWidget* container = new QWidget(  );
    this->signalLabel = new QLabel("No signal yet!");
    this->slotLabel   = new QLabel("No slot yet!");
    QVBoxLayout* layout = new QVBoxLayout(  );
    layout->addWidget( this->signalLabel );
    layout->addWidget( this->slotLabel );


    QWidget* buttonContainer = new QWidget(  );
    QVBoxLayout* buttons = new QVBoxLayout(  );
    buttonContainer->setLayout( buttons );
    for(int i = 0; i < 2; i ++ ){
        QPushButton* currentButton = new QPushButton( QString::number(i) );
        buttons->addWidget( currentButton );
    }


    mainLayout->addWidget( container );
    mainLayout->addWidget( buttonContainer );



}

The idea is:
1) set the main layout of the window
2) create the labels into a container widget and add them to such container 
using its layout;
3) create a container for buttons and add buttons to the container
4) add the two containers to the above main layout.

Any suggestion is welcome.

Thanks,
Luca