QTabWidget size depending on current Tab

I've a QTabWidget, which contains widgets of different heights (their widths are fixed), however, the default implementation ofQTabWidget selects the biggest widget's height as own height.

What I would like to know if there's a (possible fast) way to change the size of QTabWidget depending on its current tab, to save space when smaller tabs are shown.

You can set the size policy of the widget that is displayed to QSizePolicy::Preferred and the other ones to QSizePolicy::Ignored. After that call adjustSize to update the sizes. For example you can connect the currentChanged signal of the QTabWidget to a slot :

connect(ui->tabWidget,SIGNAL(currentChanged(int)),this, SLOT(updateSizes(int)));

And set size policies and adjust sizes accordingly in the slot :

void MainWindow::updateSizes(int index)
{
    for(int i=0;i<ui->tabWidget->count();i++)
        if(i!=index)
            ui->tabWidget->widget(i)->setSizePolicy(QSizePolicy::Ignored, QSizePolicy::Ignored);

    ui->tabWidget->widget(index)->setSizePolicy(QSizePolicy::Preferred, QSizePolicy::Preferred);
    ui->tabWidget->widget(index)->resize(ui->tabWidget->widget(index)->minimumSizeHint());
    ui->tabWidget->widget(index)->adjustSize();
    resize(minimumSizeHint());
    adjustSize();
}