Changing colors of QProgressBar

[mastupristi]

Hi,

I need to change the color of a progress bar depending on its value.

I tried in some ways with poor results.

QPalette pal = ui->progressBar->palette();
    pal.setColor(QPalette::Normal, QPalette::Base, QColor("red"));
    //pal.setColor(QPalette::Highlight, Qt::red);
    //pal.setColor(QPalette::Background, Qt::red);
    ui->progressBar->setPalette(pal);

QPalette pal = ui->progressBar->palette();
    pal.setColor(QPalette::Normal, QPalette::Base, QColor("red"));
    //pal.setColor(QPalette::Highlight, Qt::red);
    //pal.setColor(QPalette::Background, Qt::red);
    ui->progressBar->setPalette(pal);

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I also tried to change stylesheet from QT Creator, but nothing happens.

where am I wrong?

I'm using Qt 4.7, QT Creator 2.0.1, Ubuntu 10.10 64 bit.

thanks