QTabWidget size depending on current Tab

Question

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.

Answer 1

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();
}

Answer 2

OK so this question was already has an accepted answer, but I decided to share my solution, which works remarkably well. It is a small code snippet based on Nejat's answer, and it will work for QTabWidget and QStackedWidget.

template <typename T>
void pack(T *stacked)
{
    for(int i=0; i<stacked->count(); i++) {
        stacked->widget(i)->setSizePolicy(QSizePolicy::Ignored, QSizePolicy::Ignored);
    }
    QWidget *widget=stacked->currentWidget();
    widget->setSizePolicy(QSizePolicy::Minimum, QSizePolicy::Minimum);
    widget->resize(widget->minimumSizeHint());
    widget->adjustSize();
    stacked->resize(stacked->minimumSizeHint());
    stacked->adjustSize();
}

NOTE: I used Minimum instead of Preferred to make it take up as small size as possible. Also, this solution expects the currently selected widget to already be set.