Display an image in a QGraphicsview

[emilio]

Hello,

I'm developing an application that displays a default image in a QGraphicsiew (named viewer) when it's executed and displays other image when a button it's clicked but my code doesn't work:

main.cpp

int main(int argc, char *argv[])
{
    QApplication a(argc, argv);
    catiz w;    
    w.showFullScreen();
 
    return a.exec();
}

int main(int argc, char *argv[])
{
    QApplication a(argc, argv);
    catiz w;    
    w.showFullScreen();

    return a.exec();
}

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catiz.cpp

...
catiz::catiz(QWidget *parent) : QWidget(parent),ui(new Ui::catiz)
{
    ui->setupUi(this);
 
    QGraphicsScene scene;
    QPixmap pixmap(":/init.jpg");
    scene.addPixmap(pixmap);
    ui->viewer->setScene(&scene);
}
...

...
catiz::catiz(QWidget *parent) : QWidget(parent),ui(new Ui::catiz)
{
    ui->setupUi(this);

    QGraphicsScene scene;
    QPixmap pixmap(":/init.jpg");
    scene.addPixmap(pixmap);
    ui->viewer->setScene(&scene);
}
...

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What could be wrong? I'm using QtCreator.

Best regards.