QWidget over current widget - it's in place, but not painted

[googie]

Hi,

I just created simple "QMainWindow" application, just from QtCreator New Project wizard. I've added two push buttons into center widget, then each of them connected (clicked() signal) with slots:

void MainWindow::on_pushButton_clicked()
{
    w = new QWidget(this);
    w->move(0, 0);
    w->setFixedSize(50, 200);
    w->setVisible(true);
}
 
void MainWindow::on_pushButton_2_clicked()
{
    delete w;
}

void MainWindow::on_pushButton_clicked()
{
    w = new QWidget(this);
    w->move(0, 0);
    w->setFixedSize(50, 200);
    w->setVisible(true);
}

void MainWindow::on_pushButton_2_clicked()
{
    delete w;
}

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What bothers me is that after pressing button1, widget is created and resized as expected, but it's not painted at all. I mean I see that the widget is there, because it covers left part of the upper push button, therefore the pushbutton doesn't light-up on mouse over event, but when I move mouse right the pushbutton lights up. But... the widget itself is not painted at all, like it was transparent

What am I missing here? Shouldn't the widget paint itself as empty rectangle, instead of transparent one?

[Santosh Reddy]

What am I missing here? Shouldn't the widget paint itself as empty rectangle, instead of transparent one?

A QWidget by default has nothing to paint, it just empty. This is expected behavior.

[googie]

I see. What about QFrame? I tried with that too, with same result.

[Santosh Reddy]

void MainWindow::on_pushButton_clicked()
{
    w = new QFrame(this); //<<<<<<<<<<<<< change w to QFrame *
    w->move(0, 0);
    w->setFixedSize(50, 200);
    w->setVisible(true);
    w->setFrameStyle(QFrame::Box); //<<<<<<<<<<<<<< this is required
}
 
void MainWindow::on_pushButton_2_clicked()
{
    delete w;
}

void MainWindow::on_pushButton_clicked()
{
    w = new QFrame(this); //<<<<<<<<<<<<< change w to QFrame *
    w->move(0, 0);
    w->setFixedSize(50, 200);
    w->setVisible(true);
    w->setFrameStyle(QFrame::Box); //<<<<<<<<<<<<<< this is required
}

void MainWindow::on_pushButton_2_clicked()
{
    delete w;
}

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[googie]

Found it! QWidget::setAutoFillBackground(true) was the key.