How to put background of QWidget under other widgets in a QGridLayout

Question

I've been hours trying to understand(googling) why my widgets are not shown in a QWidget children I am using as a Windows.

The children are mostly QLabel and some QSliders. The Layout is a QGridlayout

here it is some of my window code:

FenPrincipale::FenPrincipale()
    {
        this->setWindowTitle("Premier Test");
        this->resize(400, 200);
        QPalette palette;
        palette.setBrush(this->backgroundRole(), QBrush(QImage("images/metal400x200.png")));

        this->setPalette(palette);
        /*
        this->setStyleSheet("background-image: url(images/metal400x200.png); "
                            "background-position: top left; "
                            "background-repeat: repeat-xy;"
                            );
        */

        buildChildren();
        buildLayout();

        this->setLayout(layout_principale);
    }

EDIT:

How my children is built

void FenPrincipale::buildChildren()
{
    m_title = new QLabel("MonTest");
    m_nextPageButton = new QLabel(">");

    m_line = new QLabel("Slide here");
    m_labelSlider = new QSlider;
    m_result = new QLabel("Result");

    /* 
     * Other children is set here...
    */
}

Voilà the result:

I tried changing fonts and other methods to set the background but the background is always shown over the other widgets.

Am I missing something?

Answer 1

It looks like you were close with the style sheet implementation. I get the correct result with the following:

setStyleSheet("QMainWindow { background-image: url(:/images/metal400x200.png) } ");